bookmark_borderDraft: William Lane Craig on the Evidential Argument from Evolution

This is a draft article I’ve been working on. Any feedback would be appreciated.


Abstract: Paul Draper defends what may be called an “evidential argument from evolution” against theism, viz., an argument which purports to show that evolution constitutes strong evidence against theism. In response to this argument, William Lane Craig argues that Draper’s argument depends upon three “dubious” probability estimates. I examine one by one Craig’s objections to these estimates and show how they miss the mark.


Introduction

The idea that evolution is somehow a threat to “religion” is nothing new. Ever since the publication of Charles Darwin’s Origin of Species, there have been allegations of a “war” between “science” and “religion,” with evolution arguably constituting one of the war’s front lines. For most of this “war’s” history, the philosophical “fighting” has focused on questions of logical compatibility, such as whether evolution is compatible with Christian theism (specifically, with a literal interpretation of the Biblical book of Genesis) or, more broadly, whether it is even compatible with “mere” or “generic” theism; no one had bothered to make a serious effort to consider, apart from questions of logical compatibility, whether the truth of evolution might constitute evidence against theism even if it is consistent with it. This changed in 1997. Philosopher of religion Paul Draper, well-known for writing what is widely considered one of the best versions of the argument from evil (1996), developed what may be called the “evidential argument from evolution.” It takes the following form:

(1) Evolution is antecedently much more probable on the assumption that naturalism is true than on the assumption that theism is true.
(2) The statement that pain and pleasure systematically connected to reproductive success is antecedently much more probable on the assumption that evolutionary naturalism is true than on the assumption that evolutionary theism is true.
(3) Therefore, evolution conjoined with this statement about pain and pleasure is antecedently very much more probable on the assumption that naturalism is true than on the assumption that theism is true. (From 1 and 2)
(4) Naturalism is at least as plausible as theism.
(5) Therefore, other evidence held equal, naturalism is very much more probable than theism. (From 3 and 4)
(6) Naturalism entails that theism is false.
(7) Therefore, other evidence held equal, it is highly probable that theism is false. (From 5 and 6) (Draper 1997)

Strictly speaking, the argument is both an evidential argument from evolution and an evidential argument from evil: (1) appeals to the fact of evolution, whereas (2) appeals to facts about pain and pleasure (a type of so-called “natural evil”).
The argument includes several propositions in the relevant background knowledge:

B1: Pain and pleasure, if they exist, have intrinsic moral value.
B2: A physical universe—which operates according to natural laws, is intelligible, and which supports the possibility of intelligent life—exists.
B3: Living things, including sentient beings, exist on Earth. These sentient beings include, but are not limited to, human beings.
B4: Some (Earthly) sentient beings are not moral agents but are biologically very similar to (Earthly) embodied moral agents.
B5: Humans are goal-directed organic systems, composed of parts that systematically contribute to the biological goals of these systems.

So the argument can be restated as follows:

(1) Pr(E| N & B) >! Pr(E | T & B).
(2) Pr(P | E & N & B) >! Pr(P | E & T & B).
(3) Pr(E & P | N & B) >!! Pr(E & P | T & B). (From 1 and 2)
(4) Pr(|T|) =< Pr(|N|).
(5) Pr(N | E & P & B) >!! Pr(T | E & P & B). (From 3 and 4)
(6) Naturalism entails that theism is false.
(7) Therefore, Pr(T | E & P & B) <!! 1/2. (From 5 and 6)

In the twenty years since it was published, the evidential argument from evolution has attracted the attention of several philosophers, including William Lane Craig (2003, pp. 548-550), Alvin Plantinga (2011), and Daniel Howard-Snyder (2017). In this paper I want to critically assess Craig’s objections. Now if Craig claimed no more with respect to the evidential argument from evolution than the truism that “one man’s modus ponens is another man’s modus tollens,” namely, that one’s degree of belief in the falsity of an argument’s conclusion can exceed one’s degree of belief in an argument’s key premise (Craig 2003, p. 549), then the defender of the evidential argument from evolution would have no dispute with Craig, pointing out that the argument’s “other evidence held equal” clause preempts Craig’s punting to theistic arguments. Fortunately for discussion’s sake, Craig’s appraisal of the evidential argument from evolution is mostly independent of his appeal to theistic arguments.  According to Craig, “Draper’s argument hinges on three probability estimates which seem dubious in light of our discussion” (Craig 2003, p. 549). In this response, I hope to show that the argument is, in fact, considerably stronger than Craig acknowledges.

Part 1: Craig’s Objections in His Written Work

First Objection: The Argument for Pr(|T|) =< Pr(|N|)

Craig’s first objection is that Draper (1997) assumes that theism and naturalism have equal prior probabilities. In Craig’s (2003, p. 549) words, Draper assumes that

naturalism and theism are equally probable with respect to our general background knowledge (Pr (N) = Pr (T)), which we have seen reason to dispute (recall chaps. 23-24).

As an objection to Draper 1997, however, this is simply misguided.
(i) First, Craig has confused prior probability with intrinsic probability. The former is a measure of the probability of a hypothesis conditional upon the relevant, extrinsic background information, whereas the latter is the probability of a hypothesis determined solely by intrinsic factors related to the content of a hypothesis, e.g., its scope and modesty. Allow me to introduce some mathematical symbols to make this clear:
Let Pr(|X|) =df. the intrinsic probability of X
Let Pr(X | B) =df. the prior probability of X conditional upon background information B
So Craig’s objection assumes that Draper’s argument either contains (or implies) a premise which says:

(4′) Pr(T| B) = Pr(N | B).

But this is false. The actual premise in Draper’s argument is:

(4) Naturalism is at least as plausible as theism, i.e., Pr(|T|) =< Pr(|N|).

Even if Craig were correct that theism had a higher prior probability than naturalism, this would be irrelevant to (4), which states that theism is not intrinsically more probable than naturalism. So far as I am aware, Craig has never interacted with any of Draper’s work on intrinsic probability. (write a lot more here)
(ii) Even if Draper’s argument had claimed that theism and naturalism contained equal prior probabilities, Craig’s selection of background propositions—i.e., the propositions which constitute the relevant background knowledge—is biased. Again, Craig (2003, p. 49) writes:

naturalism and theism are equally probable with respect to our general background knowledge (Pr (N) = Pr (T)), which we have seen reason to dispute (recall chaps. 23-24).]

What, precisely, were the reasons offered in chapters 23 and 24? The cosmological, teleological, axiological, and ontological arguments. Here I think Craig has not expressed himself very well. What could it mean to say that a set of arguments constitutes “our general background knowledge”? I am not even sure what that means. One option would be to include the conclusions of those arguments in our background knowledge:

B6. A maximally great being exists, i.e., a maximally great being exists in every possible world including the actual world. (Craig 2003, p. 496)
B7. The universe has a cause. (Craig 2003, p. 468)
B8. The explanation of the existence of the universe is God. (Craig 2003, p. 466)
B9. The fine-tuning of the universe is due to design. (Craig 2003, p. 484)
B10. God exists. (Craig 2003, p. 495)

That can’t be right because several of those conclusions (B6, B8, and B10) either explicitly state or imply that God exists. It’s illegitimate to include, in the background knowledge of a Bayesian argument, a proposition which entails the truth or falsity of the rival explanatory hypotheses under consideration. But three of these conclusions (B6, B8, and B10) either state or imply God’s existence, which renders them unsuitable for inclusion in the relevant background knowledge of an evidential argument about God’s existence. Furthermore, B6, if true, would entail that God’s existence is metaphysically necessary. It would be very odd, I think, to include “God’s existence is metaphysically necessary” in the background knowledge of any evidential argument against God’s existence. If God’s existence were metaphysically necessary, then we wouldn’t say that fact ought to be included in an evidential argument against God’s existence. Rather, we would say that all evidential arguments against God’s existence are fundamentally misguided, since there is no possible world in which God does not exist.
Another option would be to include in our background knowledge the key evidence to be explained in each of those arguments.

B6′. It is rational to believe that it is possible that a maximally great being exists. (From Plantinga’s ontological argument)[1]
B7′. The universe began to exist. (From the kalam cosmological argument)[2]
B8′. The universe has an explanation for its existence. (From the Leibnizian cosmological argument)[3]
B9′. The universe is life-permitting. (From Craig’s teleological argument)[4]
B10′. Objective moral values exist. (From the axiological argument)[5]

This second option–focusing on the evidence to be explained–seems to be the most favorable to Craig’s goal of boosting the prior probability of theism over naturalism.
The second option fails, however, because it violates the inductive Rule of Total Evidence. Why does it violate the Rule of Total Evidence? Because it considers only some propositions (those which Craig believes to be favorable to theism) while ignoring other propositions (those favorable to naturalism). For example:

B11. It is rational to believe that it is impossible that a maximally great being exists.[6]
B12. The physical exists. (From the evidential argument from physicality)[7]
B13. It is rational to believe that it is impossible for a timeless being to create anything.
B14. So much of our universe is intelligible without appeal to supernatural agency. (From the evidential argument from the history of science)[8]
B15. Conscious states in general are dependent upon the physical brain. (From the evidential argument from mind-brain dependence)[9]
B16. The world contains an abundance of tragedy and relatively little triumph. (From the evidential argument from triumph and tragedy)[10]

To sum up: Craig’s first objection mistakenly treats intrinsic probability as synonymous with prior probability. Furthermore, even if premise (4) had appealed to prior probability, Craig would still have failed to show that theism enjoys a higher prior probability than naturalism.

Second Objection: The Argument for Pr(P | E & N & B) >! Pr(P | E & T & B)

Craig’s second objection appeals to what I call the “skeptical theism defense” (Lowder 2016). Craig (2003, p. 549) writes:

Second, he believes that the probability of the distribution of pain/pleasure in the world is greater on naturalism and evolution than it is on theism and evolution (Pr (P/E&N) > Pr(P/E&T)). But we have seen reason to question whether we are in an epistemic position to make justifiably this sort of probability judgement.

What reason is that?

What makes the probability [that God has no morally sufficient reasons for permitting the evils that occur] here so difficult to assess is that we are not in a good epistemic position to make these kinds of probability judgments with any sort of confidence. As finite persons, we are limited in space and time, in intelligence and insight. But the transcendent and sovereign God sees the end of history from its beginning and providentially orders history so that his purposes are ultimately achieved through human free decisions. In order to achieve his ends God may well have to put up with certain evils along the way. Evils that appear pointless or unnecessary to us within our limited framework may be seen to have been justly permitted within God’s wider framework. (Craig 2003, p. 543)

By interacting solely with Draper 1997, it appears that Craig missed the fact that Draper 1996 (p. ##) already answered this objection. To sum up: it’s possible that God has unknown reasons for allowing evil. But it’s also possible—and antecedently just as likely—that God has unknown reasons for preventing evil. So the possibilities of unknown reasons for allowing evil and unknown reasons for preventing evil “cancel out.” We’re right back where we started, namely, working with what we do know: P. In fact, this is pretty much the point of using epistemic probabilities. If we had perfect, complete information, then we wouldn’t need to use probabilities at all. So human ignorance is not a good objection to comparing Pr(P | E & N & B) to Pr(P | E & T & B).
Furthermore, as numerous philosophers (nontheists and theists alike) have pointed out, logically consistent natural theologians cannot appeal to the limitations of human cognitive abilities to defeat evidential arguments from evil (Draper 1996b, p. 188). Allow me to explain. If human cognitive limitations really did prevent us from assessing whether God has morally sufficient reasons for allowing evil, including facts about pain and pleasure, then Craig can kiss goodbye all of his arguments from natural theology for God’s existence. Consistent skeptical theists should also insist that human cognitive limitations prevent us from assessing:

  1. the antecedent probability of our universe beginning to exist on theism, i.e., Pr(beginning | theism);
  2. the antecedent probability of so-called cosmological ‘fine-tuning’ on theism, i.e., Pr(‘tuning’ | theism); and
  3. the antecedent probability of the Resurrection on theism, i.e., Pr(Resurrection | theism).

This is why logically consistent natural theologians, like Oxford University philosopher Richard Swinburne, don’t rely upon skeptical theism. Instead, they attempt to provide theodicies—explanations for why God, if He exists, would allow facts about the kinds, amounts, and distribution of evil in the world to obtain (Draper 2010, p. 18).
Finally, Craig is completely silent on Draper’s supporting arguments for believing that Pr(P | E  & N & B) !> Pr(P | E & T & B). As I read him, Draper gives three such arguments. First, our background knowledge includes the fact many other parts of organic systems are systematically connected to reproductive success. Second, Draper points out that evolutionary naturalistic Darwinism (E & N & D) provides an antecedent reason for believing that pain and pleasure, like anything else produced by natural selection, will be systematically connected to reproductive success, which is what P states. In fact, evolutionary naturalism (E&N) entails nothing that would provide an antecedent reason for doubting that pain and pleasure will resemble other parts of organic systems by being systematically connected to reproductive success. Third, given E&T, however, P would be true only if the biological goal of reproductive success and some unknown justifying moral goal happened to coincide in such a way that each could be simultaneously satisfied. That’s a really big coincidence that E & N & D doesn’t need.
Thus, on the assumption that E&N is true, it would be extremely surprising if pain and pleasure appeared to be anything but morally random, whereas on the assumption that theism is true, a discernible moral pattern would be less surprising. Draper concludes, accordingly, that (2) is true and Pr(P & E & N & B) >! Pr(P | E & T & B).

Third Objection: The Argument for Pr(E| N & B) >! Pr(E | T & B)

Craig’s third objection seeks to undercut (1) by appealing to the (alleged) improbability of life on naturalism. In his (2003, p. 549) words:

Finally, he argues that the probability of evolution on naturalism is greater than the probability of evolution on theism (Pr(E/N) > Pr(E/T)). For if naturalism is true, evolution is the only game in town; but if theism is true, God had more alternatives. But this assessment is confused. What Draper’s argument supports is the assessment that evolution is more probable relative to naturalism and the existence of biological organisms than to theism and the existence of biological organisms (Pr(E/N&B) > Pr(E/T&B)). But we have seen from our discussion of the teleological argument (chapter 23) that the existence of biological organisms (and, hence, their evolution) is virtually impossible relative to naturalism alone and that we should therefore expect a lifeless world given naturalism, which cannot be said of theism. Without his three crucial probability estimates Draper’s evidential argument from evil founders.

As an objection to (1), however, this objection is multiply flawed.
(i) I think Craig is being uncharitable to Draper. In Draper’s writings, he does not explicitly refer to background knowledge in his probabilistic notation; thus, “Pr(E / N)” can be charitably restated in its more explicit form as, “Pr(E / N &  B),” where “B” represents the relevant background information. Indeed, this is precisely how I have presented Draper’s argument in this article. The key point here is that, in Draper’s original article, “probability of evolution on naturalism” means “probability of evolution on naturalism and our background information” and “probability of evolution on theism” means “probability of evolution on theism and our background information.”
(ii) What about the possibility of biological organisms on naturalism alone? Here Craig attempts to change the subject by appealing to the teleological argument. Let’s grant, but only for the sake of argument, that the probability of a life-permitting world on theism is greater than the probability of a life-permitting world on naturalism, i.e., Pr(life-permitting world | T) > Pr(life-permitting world | N). That fact, if it is a fact, is not of obvious relevance to the evidential argument from evolution. For the evidential argument from evolution compares the antecedent probability of evolution on naturalism and on theism, i.e., Pr(E | N & B) > Pr(E| T & B). Craig seems to think that if he can show that if a life-permitting world is extremely improbable on naturalism, it somehow follows that (1) is false. In other words, Craig seems to move from:

The probability of a life-permitting world on naturalism is extremely low, i.e., Pr(life-permitting world | N) << 0.5.

to:

It is false that the probability of evolution on naturalism (and background information) is greater than the probability of evolution on theism (and background information), i.e., it is false that Pr(E | N & B) > Pr(E| T & B).

The problem, however, is that this does not follow. For the sake of argument, it may be the case that the fact that our universe is life-permitting is more probable on theism than on naturalism, but, given that our universe is life-permitting, the fact that all living things are the gradually modified descendants of earlier living things is evidence favoring naturalism over theism. Indeed, this is precisely Draper’s (2001) position!
 
 

References

Craig, William Lane (2003). “The External Problem of Evil,” in J.P. Moreland and William Lane Craig, Philosophical Foundations for a Christian Worldview (pp. 548-550). Downers Grove: InterVarsity.
Draper, Paul (1996). “Pain and Pleasure: An Evidential Problem for Theists.” Noûs, 23 (3): 331-350. Reprinted in Daniel Howard-Snyder (Ed.), The Evidential Argument from Evil (pp. 12-29). Indianapolis, IA: Indiana University Press.
Draper, Paul (1997) “Evolution and the Problem of Evil” in Louis Pojman (Ed.), Philosophy of Religion: An Anthology (pp. 219-230). 3rd ed., Belmont: Wadsworth.
Draper, Paul (2001). “Seeking But Not Believing: Confessions of a Practicing Agnostic” in Daniel Howard-Snyder and Paul Moser (Eds.), Divine Hiddenness: New Essays (pp. 197-214). New York: Oxford University Press.
Draper, Paul (2010). “God and Evil: A Philosophical Inquiry” (October 1, 2010). Talk presented at the University of Notre Dame Ninth Annual Plantinga Lecture, Notre Dame, Indiana. <https://philreligion.nd.edu/assets/44795/1011lecture.pdf>
Howard-Snyder, Daniel (2017). “The Evolutionary Argument for Atheism” in John-Christopher Keller (Ed.), Being, Freedom, and Method: Themes from Van Inwagen (pp. 241-62). New York: Oxford University Press.
Lowder, Jeffery Jay (1998). “Summary and Assessment of the Craig-Draper Debate on the Existence of God (1998).” The Secular Outpost blog. <https://secularoutpost.infidels.org/2016/02/20/summary-and-assessment-of-the-craig-draper-debate-on-the-existence-of-god-1998/>, site accessed December 20, 2016.
Lowder, Jeffery Jay (2016). “In Defense of an Evidential Argument from Evil: A Reply to William Lane Craig.” The Secular Web. <https://infidels.org/library/modern/jeff_lowder/pain-and-pleasure.html>, site accessed September 1, 2019.
Oppy, Graham (2016). TBD
Plantinga, Alvin (2011). Where The Conflict Really Lies: Science, Religion, & Naturalism. New York: Oxford University Press.
Notes
[1] I think the truth of B6′ is far from obvious. Indeed, as Graham Oppy (2016, p. TBD) points out, “opponents of the argument are bound to challenge the acceptability” of B6. He continues, “And, of course, they do. Let’s just run the argument in reverse.” Oppy then runs the argument as follows:

There is no entity which possesses maximal greatness.
(Hence) There is no possible world in which there is an entity which possesses maximal greatness.

Oppy concludes: “Plainly enough, if you do not already accept the claim that there is an entity which possesses maximal greatness, then you won’t agree that the first of these arguments is more acceptable than the second. So, as a proof of the existence of a being which possesses maximal greatness, Plantinga’s argument seems to be a non-starter.”
[2] Even if we assume, but only for the sake of argument, that B7′ is more probable on theism than on naturalism, this argument commits the fallacy of understated evidence. Given that the universe began to exist, the fact that it began to exist with time, not in time, is more probable on naturalism than on theism.
[3] Even if we grant that the universe has an explanation of its existence, it doesn’t follow that the explanation is God. Other possible explanations include: (i) an infinite regress of contingent universes; and (ii) our universe’s factual necessity. If our universe is factually necessary, then its existence would be partially explained by its own nature (which is uncaused, beginningless, and independent / free-standing) and partially explained by virtue of other things that happen to exist (i.e., nothing around it has what it takes to knock the universe out of existence). I owe this objection to Felipe Leon.
[4] Even if we assume, but only for the sake of argument, that B9′ is more probable on theism than on naturalism, this argument commits the fallacy of understated evidence. Given that the universe is life-permitting, the fact that so much of it is hostile to life is more probable on naturalism than on theism. Furthermore, given that the universe is life-permitting, the fact that life is the result of evolution is much more probable on naturalism than on theism.
[5] B10′ is not more probable on theism than on naturalism. Theism assumes, not explains, the existence of objective moral value.
[6] TBD
[7] TBD
[8] TBD
[9] TBD
[10] TBD

bookmark_borderOpening Statement from My Debate with Frank Turek

Although I’ve recently been too busy to spend any time writing original content for this blog, I’ve decided to post my opening statement from my 2016 debate with Frank Turek. Enjoy!


Introduction

Good evening! I’d like to thank Craig Freerksen for organizing this debate. I’d also like to thank Dr. Turek for agreeing to participate. Finally, I’d like to thank all veterans, including my opponent, for defending the right to have a debate like this. Now, speaking of our country, I thought I’d borrow a slogan from the presidential campaign. I’m not selling any hats, but I’m here to “make atheism great again.”

Definitions

In this debate, we’ve been asked to assess what best explains reality: naturalism or theism? Before we can answer that question, we need to have some idea of what we’re talking about, so let me begin by defining some terms.
First, by “naturalism,” I mean the view that the physical exists and, if the mental exists, the physical explains why the mental exists.[1] If naturalism is true, then there are no purely mental beings which can exist apart from a physical body and so there is no God or any person or being much like God.
Second, by “supernaturalism,” I mean the view that the mental exists and, if the physical exists, the mental explains why anything physical exists.[2] If supernaturalism is true, then there is no purely physical matter which can exist without some sort of ultimate mental creator.
Third, “personal supernaturalism” is a type of supernaturalism; it adds on the claims that one or more personal mental entities exist and, if a physical world exists, it or they produced the physical world for a purpose.[3]
Fourth, “theism” is a type of personal supernaturalism; it adds on the claim that there is just one mental entity, God, who is all-powerful, all-knowing, and morally perfect.[4]
Finally, fifth, “otherism” is a catch-all category. It says that both naturalism and supernaturalism are false.[5]
Now the question before us in tonight’s debate is this. What best explains reality: theism or naturalism?
In support of a naturalistic answer to that question, I’m going to defend three basic contentions:
(1) The best explanation is the explanation with the overall greatest balance of intrinsic probability and accuracy;
(2) Naturalism is an intrinsically more probable explanation than theism; and
(3) Naturalism is a more accurate explanation than theism.

First Contention

Let’s look, then, at my first basic contention: the best explanation is the explanation with the overall greatest balance of intrinsic probability and accuracy.
By “intrinsic probability” of a hypothesis, I mean the probability independent of the evidence we have for or against it. The intrinsic probability of a hypothesis is determined entirely by its modesty and coherence.[6]
By “accuracy” of a hypothesis, I mean the degree to which a hypothesis’s predictions correspond to reality. We measure accuracy by looking at “evidence.”
By “evidence” I mean something which makes something else more probable than it would have been otherwise. Let me give you an example.[7] Imagine you have two jars of red and blue jellybeans. In the first jar, 90% of the jellybeans are blue and the rest are red. In the second jar, 90% of the jellybeans are red and the rest are blue.
Now imagine you are handed a jelly bean from one of the jars, but you don’t know which jar it came from. If it’s a blue bean, that’s evidence it came from the first jar, not the second. The blue bean doesn’t disprove that it came from the second jar because the second jar also has blue beans, but it’s more likely that it came from the first because there are more blue jellybeans in the first than in the second. Similarly, if it’s a red bean, that’s evidence it came from the second jar. The red bean doesn’t disprove that it came from from the first jar because the first jar also has red beans, but it’s more likely that it came from the second because it has many more red beans.
Mathematicians have a formula called Bayes’ Theorem, which can be used to specify the relationship between intrinsic probability, accuracy, and the overall or final probability of a hypothesis. It follows from Bayes’ Theorem that a hypothesis is probably true, just in case it has a greater overall balance of intrinsic probability and explanatory power than do its alternatives collectively.

Second Contention

Let’s look, then, at my second basic contention: naturalism is an intrinsically more probable explanation than theism.
Intrinsic probability is determined by modesty, coherence, and nothing else. By “modesty,” I mean a measure of how much the hypothesis asserts.[8] The more a hypothesis claims, the more ways there are for it to be false and so, before we start looking at evidence, the less likely it is to be true.
By “coherence,” I mean a measure of how well the parts of a hypothesis fit together.[9] If the different parts count against each other, the hypothesis is less coherent and less likely to be true.
Now consider naturalism and supernaturalism. They are symmetrical claims: naturalism claims that the physical explains the mental, while supernaturalism claims that the mental explains the physical. Both claims are equally modest and equally coherent. Before examining the evidence, both positions are equally likely to be true.[10]
With these definitions in mind, then, I can now defend my second contention. Theism is a type of supernaturalism but could be false even if supernaturalism is true. Furthermore, theism is less modest than either supernaturalism or naturalism. Therefore, before we look at evidence, it is less likely to be true than supernaturalism or naturalism.[11] But that entails that naturalism is intrinsically more probable than theism.

Third Contention

Finally, let’s move onto my third contention: naturalism is a more accurate explanation than theism for many facts.
I’d like to present seven lines of evidence that are red jellybeans, i.e., things more probable on naturalism than on theism.[12]

Physical Matter

(1) Naturalism is the best explanation for the fact that physical reality exists.[13]
If naturalism is true, then physical reality must exist. That’s just part of what naturalism means.
If theism is true, however, things look quite different. The existence of physical reality doesn’t disprove theism; if God exists, God could have created physical space, matter, and energy as part of a plan to create a universe for human beings. But God could have also chosen to create other minds without physical bodies, such as angels. Or God could have chosen to create nothing at all. In other words, God’s existence doesn’t require a physical reality.
So because the physical has to exist on naturalism but does not have to exist on theism, it follows that the existence of physical reality is evidence favoring naturalism over theism.

Success of Science

(2) Naturalism is the best explanation for the fact that science has been so successful without the supernatural.[14]
Imagine a library that contains textbooks for all of the sciences—such as physics, chemistry, and biology—and summarizes current scientific knowledge. The percentage of such knowledge which makes no appeal to the supernatural is extremely high.
Of course, one hears about specific scientific questions which (allegedly) do not have a plausible naturalistic explanation, such as cosmological fine-tuning, the origin of life, and consciousness. But, even if that is or were true, the history of science contains numerous examples of naturalistic explanations replacing supernatural ones and no examples of the reverse. Indeed, naturalistic explanations have been so successful that even most theists concede that supernatural explanations are, in general, unlikely to be true.
Such explanatory success is just what we would expect on naturalism–which entails that all supernatural explanations are false–than it is on theism.[15] And that’s my second line of evidence against theism.

Biological Evolution

(3) Naturalism is the best explanation for the fact that complex life  evolved from simple life.[16]
I’m going to list five scientific facts which support biological evolution. Since Dr. Turek likes acronyms, I’m going to give you the evidence in an acronym, BONES.

  • B is for biogeography;
  • O is for vestigial organs;
  • N is for natural selection;
  • E is for embryology; and
  • S is for stratified fossil record.

Let’s look very briefly at each of these.

Biogeography

First, the evidence indicates that the habitats of plants and animals are distributed in a puzzling way. For example, why are there no land-based mammals on any island more than 300 miles away from the mainland? As University of Chicago biologist Jerry Coyne puts it, “The biogeographic evidence for evolution is now so powerful that I have never seen a creationist book, article, or lecture that has tried to refute it.”[17]

Vestigial Organs

Secondly, a variety of animals have organs which display traits that would be unnecessary if the organs had been designed from scratch, but would have been useful to an ancestor.

Natural Selection

Thirdly, when the genetic differences between living things provides an advantage, things with that advantage tend to be more successful at survival and reproduction than things without that advantage. This is the essence of the process Darwin called natural selection.

Embryology

Fourthly, as Coyne points out, the evidence indicates that all vertebrate embryos begin development in the same way, looking like embryonic fish, but as they progress, they often go through strange contortions before reaching their final form.[18]

Stratified Fossil Record

Fifthly, the available fossil evidence indicates that as one goes from the oldest to the youngest layers of the fossil record, the layers show gradual change from simple to more complex life forms.
Taken together, the BONES evidence is much more probable on biological evolution (which says that complex life evolved from simple life through trans-generational genetic change)[19] than it is on special creationism (which says that God created all life virtually simultaneously).[20]
If either naturalism or supernaturalism is true, life could exist or not exist. If naturalism is true and life exists, evolution pretty much has to be true. But if theism is true, God didn’t have to use evolution. Furthermore, since theism says that at least one mind existed before any physical matter, it gives a reason to expect that any other minds are fundamentally nonphysical. But that, in turn, leads us to predict conscious life was created independently of nonconscious life, contrary to what evolution claims.[21] So theism predicts that evolution is false.
Thus, the scientific fact of evolution is more likely on naturalism than on theism, and so that’s my third line of evidence against theism.

Pain and Pleasure

(4) Naturalism is the best explanation for the biological role (and moral randomness) of pain and pleasure.[22]
I’m going to give three lines of evidence.
First, moral agents experiencing biologically useful pain and pleasure.
Suppose you are a teenager sleeping in a hotel that has caught on fire. The hotel is old and doesn’t have smoke alarms. The fire gets closer and closer to you until you are actually in pain from the smoke and the intense heat. Your pain wakes you up in time for you to escape; you survive and start a family in your twenties. Your pain in this case was biologically useful because it contributed to your survival. This is just what we would expect on naturalism (and human beings are the products of evolution by natural selection).
Second, moral patients experiencing biologically useful pain and pleasure.
Most human beings are moral agents, people who can be held responsible for their actions and their consequences. But some human beings, such as young children and humans with certain mental disabilities, as well as non-human sentient animals, such as primates and dolphins, are moral patients: sentient beings who can be harmed from their own point of view, but are not responsible for their actions.
On naturalism, we would expect that (biological) sentient beings, including moral patients, would experience pain and pleasure because moral patients are biologically similar to moral agents. On theism, however, we would predict that moral patients do not suffer the same kind of pain as moral agents because such pain plays no known moral role in the lives of the moral patients who experience it.
Third, sentient beings experiencing gratuitous pain and pleasure.
Consider, for example, an animal trapped in a forest fire, suffering horrific pain as it slowly burned to death. On the one hand, this kind of pain is biologically appropriate: it is biologically useful that animals in general feel pain when they come in contact with fire. But, on the other hand, this specific instance of pain was not biologically useful because it did not contribute to the biological goals of survival or reproduction.
On naturalism, this is just what we would expect.  If naturalism is true, all animals are the byproducts of unguided evolution by natural selection, which is both indifferent to suffering and incapable of preventing it.
But if theism is true, God could “fine tune” animals so that they only experience physical pain and pleasure when it was morally necessary. So theism leads us to expect that pain and pleasure are fundamentally moral phenomena, which just happens to be connected to the biological goals of survival and reproduction. That’s a huge coincidence that naturalism doesn’t need.
So this evidence is very much more probable on naturalism than on theism.

Mind-Brain Dependence

(5) Naturalism is the best explanation for the fact that human minds are dependent upon the physical brain.[23]
Philosopher Paul Draper of Purdue University puts it this way: “Consciousness and personality are highly dependent on the brain. Nothing mental happens without something physical happening.”[24] Now Michael Tooley, a philosopher at the University of Colorado at Boulder, has stated five lines of evidence in support of this claim.[25]

  • When an individual’s brain is directly stimulated and put into a certain physical state, this causes the person to have a corresponding experience.
  • Certain injuries to the brain make it impossible for a person to have any mental states at all.
  • Other injuries to the brain destroy various mental capacities. Which capacity is destroyed is tied directly to the particular region of the brain that was damaged.
  • When we examine the mental capacities of animals, they become more complex as their brains become more complex.
  • Within any given species, the development of mental capacities is correlated with the development of neurons in the brain.

Take together, this evidence is much more probable on physicalism, which says that the mind is made only of physical matter, than it is on dualism, which says says that the mind is made of two substances (the physical and the mental). if God exists, God is not in any sense dependent on physical arrangements of matter. So theism entails the existence of at least one unembodied mind. Furthermore, if God wanted to create other minds, he didn’t need them dependent on physical brains.
So the dependence of human minds on brains is evidence against the existence of any being who is supposed to have an unembodied mind, including God. Therefore, the physical nature of minds is evidence favoring naturalism over theism.

Empathy and Apathy

(6) Naturalism is the best explanation for the neurological basis of empathy and apathy, including some moral handicaps.[26]
In many cases, our ability to choose do morally good actions depends upon our having properly functioning emotional capacities, especially empathy, i.e., our ability to identify what someone else is thinking or feeling and to respond to their thoughts and feelings with an appropriate emotion.[27]
We now know, thanks to the relatively new discipline of neuroscience, that certain brain abnormalities cause people to experience less or even no empathy.[28] According to Simon Baron-Cohen of Cambridge University, “There is a consensus in neuroscience that at least ten interconnected brain regions are involved in empathy.”[29] These regions are shown on the slide.
For example, violent psychopaths may know in some abstract sense that their behavior is morally wrong, but utterly lack empathy.[30]
While theism is compatible with a neurological basis for moral handicaps, the fact that at least some moral handicaps can be explained neurologically is much more probable on naturalism than on theism. If theism is true, then that means both 

(a) God creates some human beings with moral handicaps that are not the result of the freely chosen actions of any human being;

and

(b) These moral handicaps make it more likely that they will harm others.

What moral justification would God have for allowing both (a) and (b) to obtain? This seems utterly surprising and completely random from a theistic, moral point of view, but precisely what we would expect on naturalism (and blind nature is indifferent to the moral consequences of brain abnormalities).[31]

Nonresistant Nonbelief

(7) Naturalism is the best explanation for nonresistant nonbelief (in God).[32]
Imagine you’re growing up in an orphanage and I told you I had met a man who claims to be your father and who really wants a relationship with you. Days, weeks, even months go by but you never actually meet your father. You never get a card, letter, phone call. In fact, the only evidence that your father is alive is my claim that he exists. Why haven’t you heard from him? Perhaps your father is ashamed for abandoning you. Or maybe he’s a prisoner of war and his captors won’t even let him write you. Although you hope your father is alive and wants to meet you, you remain skeptical.
Just as you do not believe your father is alive and wants to meet you, there are people who do not believe that God exists.[33] But notice that, whatever reasons we might invent to explain your earthly father’s absence do not explain their heavenly father’s absence.
At least some of the people who deny God’s existence are “nonresistant” nonbelievers. As philosopher John Schellenberg explains, their nonbelief is “not in any way the result of their own emotional or behavioral opposition towards God or relationship with God or any of the apparent implications of such a relationship.”[34] Such nonbelievers are open to having a relationship with God—in fact, they may even want it—but are unable to have such a relationship. But why, if God exists, does that happen?
On naturalism, blind nature doesn’t care whether anyone believes in God and so the fact of nonresistant nonbelievers is hardly surprising. On theism, however, this fact is very surprising. On theism, we would expect a perfectly loving God to always make a meaningful relationship available to those He loves.

Conclusion

So, in sum, we’ve seen seven lines of evidence that naturalism is true. I also happen to think there is some evidence for theism, but that it is outweighed by the evidence for naturalism.[35] In my other speeches, I will explain why I think this as I respond to Dr. Turek’s arguments.[36]

Notes

[1] I owe this definition to Paul Draper.
[2] I owe this definition to Paul Draper.
[3] This definition is similar to, but not identical with, one offered by Paul Draper.
[4] I owe this definition to Paul Draper.
[5] I owe this definition to Paul Draper.
[6] I owe this to Paul Draper.
[7] I owe this jelly bean analogy to Paul Draper. Draper’s full analogy also includes an equal number of yellow jelly beans in both jars, where yellow signifies something that is equally likely to have come from either jar and hence is not evidence that it came from either jar. I have omitted the yellow jelly beans solely in the interest of time.
[8] I owe this definition to Paul Draper.
[9] I owe this definition to Paul Draper.
[10] Paul Draper, “God and the Burden of Proof,” Secular Outpost (July 21, 2014), https://secularoutpost.infidels.org/2014/07/21/new-by-paul-draper-god-and-the-burden-of-proof/
[11] Paul Draper, “More Pain and Pleasure: A Reply to Otte” in Christian Faith and the Problem of Evil (ed. Peter van Inwagen, Eerdmans, 2004), 41-54 at 49.
[12] Let N stand for naturalism, T for theism, and F for any of these facts. Using the symbol “Pr(F | H)” to stand for the epistemic probability that F is true conditional upon H, then the claim that some fact is evidence favoring naturalism over theism should be understood as the claim that Pr(F | N) > Pr(F | T).
[13] Jeffery Jay Lowder, “Potential Objections to Swinburne’s Cosmological Argument,” The Secular Outpost (March 17, 2014), https://secularoutpost.infidels.org/2014/03/17/potential-objections-to-swinburnes-cosmological-argument/. Note that here I am using the word “matter” as a way to provide a concrete example of something “physical.”
[14] See Keith M. Parsons, Science, Confirmation, and the Theistic Hypothesis (Ph.D. Dissertation, Kingston, Ontario, Canada: Queen’s University, 1986), 46; Paul Draper, “Evolution and the Problem of Evil” in Philosophy of Religion: An Anthology (3rd ed., ed. Louis Pojman, Wadsworth, 1997), 223-24; and idem, “God, Science, and Naturalism” Oxford Handbook of Philosophy of Religion (ed. William Wainwright, Oxford: Oxford University Press, 2004), 272-303; and Barbara Forrest, “Methodological Naturalism and Philosophical Naturalism: Clarifying the Connection” Philo 3 (2000): 7-29.
[15] Draper 2004.
[16] See Paul Draper, “Evolution and the Problem of Evil” in Philosophy of Religion: An Anthology (3rd ed., ed. Louis Pojman, Wadsworth, 1997), 219-230; cf. Louis P. Pojman, Philosophy of Religion (Mayfield, 2001), chapter 6.
[17] Jerry Coyne, Why Evolution is True (New York: Penguin, 2009), 88.
[18] Coyne 2009, 56.
[19] Draper 1997, 221.
[20] I’m using “virtually simultaneously” as a shorthand way of accounting for the seven literal days described in Genesis 1, in order to contrast that chronology with the sort of geological timescales needed for evolution.
[21] Draper 1997, 224.
[22] Paul Draper, “Pain and Pleasure: An Evidential Problem for Theists.” Nous 23 (June, 1989), 331-350.
[23] Jeffery Jay Lowder, “The Evidential Argument from Physical Minds,” The Secular Outpost (https://secularoutpost.infidels.org/2012/06/13/the-evidential-argument-from-physical-minds-apm/), June 13, 2012.
[24] Paul Draper, “Opening Statement” in William Lane Craig and Paul Draper, Does God Exist? (videotape, West Point, NY, 1996).
[25] Michael Tooley, “Dr. Tooley’s Opening Arguments”  in William Lane Craig and Michael Tooley, The Craig-Tooley Debate: Does God Exist? (http://www.leaderu.com/offices/billcraig/docs/craig-tooley2.html), 1994, spotted 25 Jan 99.
[26] Jeffery Jay Lowder, “The Evidential Argument from Physical Minds,” The Secular Outpost (https://secularoutpost.infidels.org/2012/06/13/the-evidential-argument-from-physical-minds-apm/), June 13, 2012.
[27] Simon Baron-Cohen, The Science of Evil: On Empathy and the Origins of Cruelty (New York: Basic Books, 2012), 16.
[28] Baron-Cohen 2012, 39.
[29] Baron-Cohen 2012, 28.
[30] As Baron-Cohen points out, the neurological basis for moral handicaps challenges traditional views about moral responsibility. “If zero degrees of empathy is really a form of neurological disability, to what extent can such an individual who commits a crime be held responsible for what they have done? This gets tangled up with the free will debate, for if zero degrees of empathy leaves an individual to some extent “blind” to the impact of their actions on others’ feelings, then surely they deserve our sympathy rather than punishment.” See Baron-Cohen 2012, 160.
[31] Some theists have pointed out that moral evil, such as fallen angels or demons choosing to do evil, might explain so-called “natural evils.” This argument makes the inverse point: certain natural evils explain at least some moral evil.
[32] J.L. Schellenberg, Divine Hiddenness and Human Reason (Ithaca: Cornell University Press, 1993); idem, 2007.
[33] This sentence, of course, assumes that at least some (if not most) professions of atheism are genuine. Those familiar with intra-Christian debates on apologetic methodologies will notice that I have just ruled out the claim of some (or all?) presuppositionalists, namely, that there are no atheists and instead there are only professed atheists. I agree with  John Schellenberg: “it would take something like willful blindness to fail to affirm that not all nonbelief is the product of willful blindness (even if some of it is).” See J.L. Schellenberg, “What Divine Hiddenness Reveals, or How Weak Theistic Evidence is Strong Atheistic Proof” God or Blind Nature? Philosophers Debate the Evidence (http://infidels.org/library/modern/john_schellenberg/hidden.html), 2008.
[34] Schellenberg 2008.
[35] It follows from a Bayesian approach to evidence sketched in my first contention that there can be “true evidence” for a false proposition. Consider, for example, people convicted on the basis of eyewitness testimony for crimes they didn’t commit, only to be exonerated years or decades later by DNA evidence. The eyewitness testimony was some evidence for a false proposition (“The defendant is guilty”), but it was greatly outweighed by the DNA evidence against that false proposition. The fact that there can be true evidence for false propositions should serve as a “warning flag” to anyone who wants to claim that there is absolutely no evidence for naturalism (or theism). “There is no evidence for naturalism (or theism)” does not follow from “Naturalism (or theism) is false” or even “I believe naturalism (or theism) is false.”
[36] I am grateful to Paul Draper, John Danaher, Robert Greg Cavin, and Eddie Tabash for helpful comments on a previous version of this speech.

bookmark_borderRichard Dawkins and Moral Realism

Christian apologists who love to substitute quote-mining for actual argumentation are fond of quotations like the following, in order to conclude that atheism somehow undermines morality.

In a universe of blind physical forces and genetic replication, some people are going to get hurt, and other people are going to get lucky; and you won’t find any rhyme or reason to it, or any justice. The universe we observe has precisely the properties we should expect if there is at the bottom, no design, no purpose, no evil and no good. Nothing but blind pitiless indifference. … DNA neither knows nor cares. DNA just is, and we dance to its music.
River Out of Eden (New York: Basic Books, 1996), p. 133

For people whose search for truth involves more than selectively quoting ‘hostile’ authorities, however, this quotation raises more questions than answers. Let’s start with a basic question for apologists who like to use this quote. Why are you quoting Dawkins on this point? Is it because you think he is an expert on the implications of atheism for morality? Is it because you think Dawkins has given a good argument for the conclusion that in a godless universe there is “no evil and no good”? Is it both? Or is it something else?
(1) Does the Quotation Support a Correct Inductive Argument from Authority?
While some arguments from authority can be logically correct, this one is not. Let P be the statement “If naturalistic evolution is true, then there is no good and no evil,” and let S be metaethics. Using Wesley Salmon’s schema for inductive arguments from authority,[1] we can then formulate the argument from authority as follows.

(1) The vast majority of statements made by Richard Dawkins concerning subject S are true.
(2) P is a statement made by Richard Dawkins concerning subject S.
(3) [probably] P is true.

This argument does not satisfy Salmon’s conditions for an inductively correct argument from authority, in two ways. First, even if we treat Dawkins as an expert on metaethics, the argument would still be evidentially worthless. As Salmon observed, an appeal to one group of authorities has no evidential value when another group of authorities who are equally competent disagree.[2] And there are many qualified experts on metaethics who believe P is false.[3] Second, with all due respect to Dawkins, he is not a reliable authority on subject S. He is an evolutionary biologist with a D.Phil. in biology, not a philosopher who specializes in metaethics. Therefore, premise (1) is dubious. The upshot is that this argument from authority provides literally zero evidence for statement P.
Even if we cannot accept P on the basis of Dawkins’ authority, however, it is still possible that Dawkins has a good argument for believing it. I’ll consider that possibility in a moment. For now, I want to make one other point. Have you ever noticed that Christian apologists love to quote Dawkins as a hostile witness when it supports their desired conclusion but not when it doesn’t? If Dawkins’ opinion about morality (that it’s not objective) is supposed to be evidence for an apologist’s claims about the moral implications of atheism, then Dawkins’ opinion about God (He doesn’t exist) should also be evidence for atheism.  It seems rather one-sided to appeal to Dawkins’ authority when it helps theism (by lending support to a dubious moral argument for God’s existence), but to ignore Dawkins’ authority when it hurts theism (by lending support to a robust evidential argument from evil against God’s existence).
(2) Does the Quotation State an Inductively Correct Argument against Moral Realism?
Again, here is what Dawkins wrote:

In a universe of blind physical forces and genetic replication, some people are going to get hurt, and other people are going to get lucky; and you won’t find any rhyme or reason to it, or any justice. The universe we observe has precisely the properties we should expect if there is at the bottom, no design, no purpose, no evil and no good. Nothing but blind pitiless indifference. … DNA neither knows nor cares. DNA just is, and we dance to its music.

What properties does Dawkins have in mind when he claims that the universe has the properties “we should expect” if there is no objective meaning or morality? And why would those properties be expected?
Let’s parse this quotation one step at a time. He writes: “In a universe of blind physical forces and genetic replication…” This suggests he is talking about an explanatory hypothesis I’ll call “naturalism.”

naturalism (N) =df. causal reality is limited to physical reality, i.e., there is no such things as minds which can exist apart from arrangements of matter

Continuing on, he writes, “some people are going to get hurt, and other people are going to get lucky; and you won’t find any rhyme or reason to it, or any justice.  …  Nothing but blind pitiless indifference.” This suggests that he is talking about the evidence to be explained (E).

E1. Distribution of good and evil, pain and pleasure, success and failure, triumph and tragedy, etc. is morally random.

And so a key premise in his argument against theism seems to be this:

(1) Known facts about evil are much more probable on the assumption that naturalism is true than on the assumption that theism is true, i.e., Pr(E1 | N) >> Pr(E1 | T).

In the quotation, Dawkins also writes the words, “no evil and no good.” This suggests another explanatory hypothesis:

O: ontologically objective moral values (i.e., moral goodness or “good”) and disvalues (i.e., badness or “evil”) exist.

And, again, the evidence to be explained would seem to be the same as before:

E1. Distribution of good and evil, pain and pleasure, success and failure, triumph and tragedy, etc. is morally random.

And so a key premise in his argument against O seems to be this:

(1’) Known facts about evil are much more probable on the assumption that O is false than on the assumption that O is true, i.e., Pr(E1 | ~O) >> Pr(E1 | O).

Dawkins’ argument against theism is much better than his argument against ontologically objective moral values. Dawkins’ terse statement of an evidential argument from evil is consistent with the very powerful defense of an evidential argument from evil by Purdue University philosopher Paul Draper. But what about Dawkins’ terse statement of an evidential argument against moral realism or objectivism? Not so much. It’s far from obvious why known facts about evil are much more probable on the assumption that O is false than on the assumption that O is true, i.e.,
Pr(E1 | ~O) >> Pr(E1 | O).
Dawkins writes, “DNA neither knows nor cares. DNA just is, and we dance to its music.” The problem is that DNA and O have nothing to do with each other.  There are two possibilities:
(1) DNA is indifferent to the moral value of pain and pleasure; and O is true.
(2) DNA is indifferent to the moral value of pain and pleasure; and O is false.
For example, it could be the case that moral anti-reductionism is true (and so moral properties are not reducible to non-moral properties) and the Good exists. Or it could be the case that naturalistic moral reductionism is true (and so moral properties are reducible to physical properties) and the Good is desirable; facts about universal human desires rooted in human biology help inform us about the Good.
In sum, Dawkins has overstated his conclusion. It’s far from obvious why DNA (or anything about the “universe we observe”) is just what we would expect on the assumption O is false.
Notes
[1] Wesley C. Salmon, Logic (third ed., Englewood Cliffs: Prentice-Hall, 1984), 100.
[2] Ibid.
[3] E.g., Adams; Hick; Moore; Morriston; Nielsen; Pojman; Post; Rottschaefer; Sagi and Statman; Shafer-Landau; Q. Smith; Swinburne; and Wielenberg.
More on Theistic Quote-Mining of Atheists on the Topic of Morality

More Posts by Lowder about Atheism and Morality

Posts by Other Secular Outpost Authors on Atheism and Morality

Wes Morriston’s Critiques of Attempts to Argue that Morality Needs God

Erik Wielenberg’s Critiques of Theistic Metaethics

Stephen Maitzen

John Danaher’s Critiques of Moral Arguments and Theistic Metaethics

Ex-Apologist’s Blog Posts

 

bookmark_borderIn Defense of an Evidential Argument from Evil: A Reply to William Lane Craig

Abstract: In a popular article about general arguments from evil against the existence of an all-powerful, all-knowing, and perfectly good God, William Lane Craig raises objections to such arguments that are consistent with those he earlier raised against Paul Draper’s evidential pain-and-pleasure argument from evil in an oral debate with Draper in 1998. In this article Jeffery Jay Lowder considers whether Craig’s points have any force in rebutting Draper’s writings on his pain-and-pleasure argument, ultimately concluding that they leave Draper’s argument unscathed.
LINK

bookmark_border25 Lines of Evidence Against Theism

Refutation of Anna Marie Perez

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First Paragraph

Here is Perez’s first paragraph:

Atheism is a religion.  Atheists act like Dracula confronting a cross when faced with the fact that their beliefs rely solely on faith.  They hate the word faith, even though it’s all they’ve got.  They try to make the claim that their religion is based on science, although actual science doesn’t support their claims any more than science can prove the existence of God.  When they are called out for having faith, they’ll say something like, “An absence of belief isn’t faith,” yet their claim of an absence of a belief is a lie.

Atheism is a religion in the same sense that baldness is a hair color, which is to say that atheism isn’t a religion at all. Although atheism, by itself, is not a religion; there can be atheistic religions. or example, I think some versions of Buddhism are atheistic, but I would definitely count Buddhism, in all of its forms, as a religion.
But let’s move onto her third sentence. Her third sentence is false. If she’s defining the word “faith” the same way as the Biblical book of Hebrews does (“confidence in what we hope for and assurance about what we do not see”), then she’s wrong to assume that “atheists,” without qualification, hope that no God or gods exist and that there is no afterlife. Yes, there are some atheists who hope for those things, but there are other atheists who hope for the opposite, and many more atheists who are indifferent. But if she’s defining the word “faith” to mean “belief without evidence” or even “belief against the (weight of the total) evidence,” then she’s mistaken.
Let’s start with some definitions:

naturalism (N) =df. The physical exists and, if the mental exists, the physical explains why the mental exists.
supernaturalism (S) =df. The mental exists and, if the physical exists, the mental explains why the physical exists.

Naturalism (N) and supernaturalism (S) are mutually exclusive: they cannot both be true. But they are not jointly exhaustive: they can both be false. To account for the possibility that both N and S are false, we can introduce a third, ‘catch-all’ option:

otherism (O) =df. Both N and S are false.

If N is true, then atheism is true by definition because N denies the existence of all supernatural beings, including God. So one way to defend atheism is to defend N. And one way to defend N is to present evidence which is more probable on the assumption that N is true than on the assumption that theism (T) is true. That is precisely what I am going to do here, by presenting twenty-five lines of evidence which are more probable on the assumption that N is true than on the assumption that T is true.
1. The Existence of the Universe
The universe–which may be defined as the sum total of all matter, energy, space, and time–exists. This fact is entailed by N: if N is true, then by definition the physical universe exists. But, although logically consistent with T, this fact is not entailed by T. If is true, God could create the universe, but God could also choose not to create the universe. Thus, contrary to the claims of both the Leibnizian and kalam versions of the cosmological argument, the existence of the physical universe is more probable on N than on T.[1]
In formal terms, the argument may be formulated as follows. If we let B be our background information; E be the existence of the universe; then the explanatory argument is as follows:
(1) E is known to be true, i.e., Pr(E) is close to 1.
(2) T is not intrinsically much more probable than N, i.e., Pr(|T|) is not much greater than Pr(|N|).
(3) Pr(E | N & B) =1 > Pr(E | T & B).
(4) Other evidence held equal, T is probably false, i.e., Pr(T | B & E) < 1/2.
2. The “Anti-Creation Ex Nihilo Argument”
This argument may be summarized as follows:

(1) Everything that had a beginning comes from pre-existing material.
(2) The universe had a beginning.
(3) Therefore, the universe came from pre-existing material.

Now I think it is far from certain that (2) is true. Let’s make a distinction between:

(2a) The expansion/inflation of the universe had a beginning.

and:

(2b) The universe itself had a beginning, viz., the universe began to exist.

It appears that (2a) is accepted by the vast majority of cosmologists. So let’s assume not only that (2a) is true, but that we know (2a) is true with certainty. It doesn’t follow that (2b) is true. In fact, as far as I can tell, (2b) does not enjoy the same widespread consensus among cosmologists as (2a) does. So there is reasonable doubt about (2b). But (2), like its theistic counterpart in the kalam cosmological argument, requires that (2b) is true. Because there is reasonable doubt about (2b), there is also reasonable doubt about (2).
But what if both (1) and (2b) are true? In that case, it would follow that (3) is true. But (3) entails the universe was not created ex nihilo, viz., created from (absolute) nothing. The falsity of creation ex nihilo is entailed by N (and physical reality’s existence is factually necessary and uncreated), but extremely unlikely (if not impossible) on T (and physical reality was either created ex nihilo or created ex deo [out of the being of God]).
3. The Continuing Existence of Physical Reality
Some theists, most notably Aquinas, talk about God as the “sustaining cause” of the universe. The idea is that even if the universe were eternal, it would somehow still require God to “sustain” it in existence. If God did not exist or, if God did exist but chose not to continue sustaining the universe, the universe would somehow cease to exist. So T is not only compatible with God never creating the universe at all, but also with the possibility of God creating the universe and causing or allowing it to cease to exist.
In contrast, if N is true, then there exists no being or thing capable of knocking physical reality out of existence. (If a multiverse exists, maybe there is a physical process which can “knock” baby universes out of existence just as there might be a physical process which can bring baby universes into existence. But there would be no physical process capable of knocking the multiverse as a whole out of existence.)
Since physical reality’s continuing existence is entailed by N but not by S, this is additional evidence favoring N over T.
4. The Scale of the Universe
Humans do not enjoy a privileged position in the universe, either spatially or temporally.[2] This fact is just slightly more probable on the assumption that N is true than on the assumption that T is true. Why? Because it is slightly more likely on T than on N, though unlikely on both, that there would be a reason why we would have a spatially or temporally privileged position (e.g., God’s desire to relate to us immediately after His creation of the universe rather than waiting billions of years, God’s desire to emphasize our importance to Him, etc.).
Notice that this argument does not entail the claim that we would expect human beings to have a privileged position in the universe if T is true. I, for one, don’t think we have an antecedent reason on T to expect that humans would have a privileged position in the universe. For all we know, if God exists, God may have created embodied moral agents throughout the universe. Indeed, for all we know, if God exists, God may have created embodied moral agents in an infinite number of physical universes!
Just as it is easy to imagine antecedent reasons on T why humans would have a privileged position (e.g., God’s desire to relate to us immediately after His creation of the universe rather than waiting billions of years, God’s desire to emphasize our importance to Him, etc.), it is also easy to imagine antecedent reasons on T why humans would not have a privileged position (e.g., God’s desire that the non-human scale of the universe be an illustration of the vastness of God Himself, God’s desire to increase the maximize the beauty of the universe, etc.). Let’s call the former set of reasons “privilege-supporting reasons” and the latter “privilege-defeating reasons.” Based solely on the content of T, we have no reason to assign different probabilities to privilege-supporting reasons and privilege-defeating reasons.
While the last paragraph shows that we have no reason to give either set of reasons greater weight than the other, the privilege-defeating reasons are compatible with God giving many (to say the least) non-privileged positions to humans, while there are so few privileged positions.[3] Thus, the specific way in which humans have a non-privileged position in the universe is (slightly) more probable on N than on T, even if the non-privileged position of humans in the universe (generically speaking) is equally probable on both T and N.
5. Evidence from the Hostility of the Universe to Life
So much of the universe is highly hostile to life, such as containing vast amounts of empty space, temperatures near absolute zero, cosmic radiation, and so forth. This more probable on N than it is on T.
6. The Unimpressiveness of Human Beings Compared to the Abilities of God
The omnipotence of God is taken for granted in the context of theistic arguments like the cosmological argument, the cosmic design argument (aka the misnamed ‘fine-tuning argument’), and arguments about alleged miracles. But the relationship of God’s omnipotence to his alleged creation or design of human beings is neglected. As Draper explains:

Or consider the fact that the most intelligent and most virtuous life form we know to exist is merely 20 human. While we are no doubt wondrous simians in many respects, given theism one might have expected something more impressive, something more worthy of the creative capacities and concerns of an omnipotent and omnibenevolent being.[4]

So the unimpressiveness of human beings, relative to the abilities of God, is much more probable on N than it is on T.
7. Complex Life Evolved from Simple Life
Intelligent life is the result of evolution. For a defense, see the Talk.Origins archive. See also my refutation of Perez’s third paragraph.
To be sure, biological evolution is logically compatible with theism; God could have used evolution to create life. But if T were true, God could have also used many other methods to create life, methods which are impossible if naturalism is true. Here are just two examples. First, God could have created living things according to a literal interpretation of the Genesis chronology. Second, God could have created all things simultaneously, i.e., on the same “day,” in contradiction to a literal interpretation of the Genesis chronology. Both of these examples show that God, as an omnipotent being, was not required to use evolution in order to create life.
In contrast, if N is true, evolution pretty much has to be true. Furthermore, since T implies a metaphysical dualism, it is antecedently likely on T that minds are fundamentally nonphysical entities and therefore that conscious life is fundamentally different from nonconscious life. But this in turn makes it likely that conscious life was created independently of nonconscious life–that evolution is false. Thus, the scientific fact of biological evolution is more likely on the assumption that N is true than on the assumption that T is true.[5]
8. The Biological Role (and Moral Randomness) of Pain and Pleasure
Physical pain and pleasure plays the same biological role as other biological systems, i.e., physical pain and pleasure aid survival and reproduction. But from a moral point of view, the distribution of pain and pleasure appears random.[6]
For example, consider the horrific suffering endured by someone who slowly burns to death while trapped at the top of a burning building, or the pain endured by someone dying from a terminal illness. Feeling pain while burning is generally useful because it alerts and motivates the organism to a direct threat to their survival. But such pain serves no biological use whatsoever in situations where the organism is unable to avoid death. And from a moral point of view, it is intrinsically bad that they have to experience such horrific suffering. In such cases, it would be better if they could “flip a switch” and turn off the biological structure(s) which make pain possible.
Likewise, consider the orgasmic pleasure experienced by male rapists. It’s generally useful for men to derive pleasure from orgasm because of the role it plays in reproduction. But if anything is morally bad, surely rape is. Once again, it appears that pain and pleasure play a biological role but are morally random. It’s as if certain gratuitous experiences of pain and pleasure occur only because the biological system isn’t ‘fine-tuned’ enough to prevent such experiences.
This is precisely what we would expect if N is true (and blind nature is indifferent to the moral value of pain and pleasure), but very, very much surprising if T is true (and there exists a God who would have both the means and the motive to have the morality and biology of pain and pleasure better aligned). If N is true, then all living things are the product of unguided evolution by natural selection; there seems to be no way for creatures to have evolved so that they only feel pain when it will aid survival. In contrast, if T were true, God could “fine tune” humans so that they experience pain only when it is necessary for some greater good. If God did exist, what possible reason could He have for allowing people trapped in burning buildings or people with terminal illnesses to endure such agonizing pain until they finally die? The chances that such a reason would intersect with the biological goal of survival is pretty slim. Thus, the biological role of pain and pleasure is much more likely on N than on T.
9. Intelligibility of the Universe without the Supernatural
If there is a single theme unifying the history of science, it is that naturalistic (i.e., non-supernatural) explanations work. The history of science contains numerous examples of naturalistic explanations replacing supernatural ones and no examples of supernatural explanations replacing naturalistic ones. Indeed, naturalistic explanations have been so successful that even most scientific theists concede that supernatural explanations are, in general, implausible, even on the assumption that theism is true. Such explanatory success is antecedently more likely on N–which entails that all supernaturalistic explanations are false–than it is on T. Thus the history of science is some evidence for N and against T.
10. Human Mental Dependence upon the Physical
Scientific evidence shows that human consciousness and personality are highly dependent upon the brain. In this context, nothing mental happens without something physical happening. That strongly implies that the mind cannot exist independently of physical arrangements of matter. In other words, we do not have a soul. And this is exactly what we would expect if N is true. But T predicts the opposite. First, if T is true, then God is a disembodied mind; God’s mind is not in any sense dependent on physical arrangements of matter. Second, if T is true, then souls or, more generally, minds that do not depend on physical brains, are a real possibility. It is no coincidence that theists have traditionally believed in the existence of other supernatural persons, besides God, who also have disembodied minds, e.g., angels and demons. For these reasons, then, it is hardly surprising that until neuroscience discovered the dependence of the mind upon the brain, all or virtually all theists were dualists. It was not until after these discoveries were made, were theists forced to reexamine their dualism and consider ad hoc hypotheses like dualist-interactionism instead. But if nothing mental happens without something physical happening, that is evidence against both the existence of souls and the existence of any being who is supposed to have a unembodied mind, including God. Therefore, the physical nature of minds is unlikely if T is true, but what we would expect if N is true.
11. Neurological Basis for Moral Handicaps
In many cases, our ability to choose do morally good actions depends upon our having properly functional emotional capacities, especially empathy, i.e., our ability to identify what someone else is thinking or feeling and to respond to their thoughts and feelings with an appropriate emotion.[7]  We now know, thanks to the relatively new discipline of neuroscience, that certain brain abnormalities cause people to experience less or even no empathy.[8] For example, violent psychopaths may know in some abstract sense that their behavior is morally wrong, but utterly lack the affective capacity for empathy which enables them to understand the impact of their actions on others’ feelings.[9]
While T is compatible with a neurological basis for moral handicaps, the fact that at least some moral handicaps can be explained neurologically is much more probable on N than on T. If T is true, then that means both

(a) God creates some human beings with moral handicaps that are not the result of the freely chosen actions of any human being;

and

(b) These moral handicaps make it more likely that they will harm others.

What moral justification would God have for allowing both (a) and (b) to obtain? This seems utterly surprising and completely random from a theistic, moral point of view, but precisely what we would expect on N (and blind nature is indifferent to the moral consequences of brain abnormalities).[10]
12. Flourishing and Languishing of Sentient Beings
Only a fraction of living things, including the majority of sentient beings, thrive. In other words, very few living things have an adequate supply of food and water, are able to reproduce, avoid predators, and remain healthy. An even smaller fraction of organisms thrive for most of their lives, and almost no organisms thrive for all of their lives. If naturalistic evolution is true, this is what we would expect. If all living things are in competition for limited resources, then the majority of those organisms will not survive long enough to thrive. Moreover, even those organisms that do thrive for much of their lives will, if they live long enough, deteriorate. However, if T is true, why would God create a world in which all sentient beings savagely compete with one another for survival? Does anyone really believe that this could be morally justified? The fact that so few sentient beings ever flourish is more likely on N than on T.[11]
13. Self-Centeredness and Limited Altruism of Human Beings
Humans are effectively self-centered; our tendency to behave in self-centered ways is usually much stronger than any tendency to behave in selfless ways. These selfless or altruistic behaviors can be divided into two types: kin altruism and non-kin altruism.
As Purdue University philosopher Paul Draper has argued, the mixture of moral goodness and moral badness we find in Homo sapiens is easy to explain on Darwinian naturalism.[12]  The Darwinian naturalist explanation for our overwhelming tendency towards self-centered behavior is obvious. Kin altruism is also easy to explain: behaviors that promote the survival and reproduction of my kin make it more probable that my genes will be inherited by future generations. Non-kin altruism is weaker than kin altruism and also absent more often than kin altruism. Given that kin altruism exists, this pattern or distribution is exactly what we would expect on Darwinian naturalism.
On T, either God created humans directly (special creation) or indirectly (Darwinian theism or theistic evolution).  Since God is omnipotent and omniscient, He could create humans without making them inherently self-centered. Since God is morally perfect, He would have good moral reasons for creating altruistic humans. Furthermore, He would not create inherently self-centered humans unless He had a morally sufficient reason for doing so. So given that humans are inherently self-centered, T entails both that God is not constrained by biological goals like survival and reproduction (and hence does not need to create human beings who are inherently self-centered) and that He had a morally sufficient reason for doing so. And that’s a really big coincidence that Darwinian naturalism doesn’t need.[13]
14. Triumph and Tragedy
There are three additional facts about good and evil which favor N over T.
First, to paraphrase Paul Draper, our world contains much horrific suffering and relatively little glorious pleasure. As he puts it, “Indeed, triumph is the exception and tragedy the rule on our planet, where the deepest and the best aspirations of human beings are routinely crushed by a variety of circumstances beyond their control.”[14]
Second, horrific suffering often destroys a person, at least psychologically, and prevents them from growing morally, spiritually, and intellectually.[15]
Third, many people do not seem to feel God’s comforting presence during tragedies.[16] Just as loving parents would, say, comfort a child undergoing chemotherapy, we would expect a loving God to comfort human beings who suffer as the result of tragedies. If T is true, then God loves his creatures and wants all of his creatures to love Him in return. However, many people find it hard to love God when they do not understand the reasons for their suffering and God seems so far away. In other words, even if God has a reason for allowing tragedies, He could still comfort victims of suffering so that they know He loves them. Yet there are many victims of tragedies who report not feeling God’s comforting presence. This is not at all what we would expect if T were true. However, if N is true, we would expect victims of tragedies not to experience God’s comforting presence for the simple reason that there is no God. Thus, God’s silence in the face of tragedies is much more probable on N than on T.
Now, ask yourself: if God exists, why is there so much horrific suffering and so little glorious pleasure? Even after thousands of years of theological reflection, theistic philosophers still have no idea. They just assume that there must be a reason for God allowing evil. For example, Alvin Plantinga, one of the most influential theistic philosophers of our time, admitted, “Many of the attempts to explain why God permits evil … seem to me shallow, tepid, and ultimately frivolous.”[17] Naturalists, on the other hand, have a plausible explanation: there is no all-good, all-powerful, all-knowing being to intervene. Therefore, facts about triumph and tragedy are much more likely on N than on T.
Of course, it’s logically possible that God has a reason for allowing tragedies, a reason we humans do not understand. But it’s also logically possible–and no less likely–that God has extra reasons for preventing tragedies, reasons we also do not understand.
15. Ethical Disagreement
The philosophical discipline of ethics is notorious for its controversy. Not only do philosophers disagree over general ethical theory (such as utilitarianism vs. deontological ethics), they also genuinely disagree about the morality of specific acts, like war, abortion, the death penalty, gun control, and sexual behavior.
The problem is not just that people disagree about morality. The problem is also that theists, including Christians, disagree about morality. Now this tends to be very awkward for the Christian. A Christian, at least if he admits there is genuine ethical disagreement, has to believe both that God wants humans to behave morally and that He has left them in the dark about whether specific kinds of behavior are morally acceptable.
On B, however, there is no God, just impersonal nature. And impersonal nature gives us even less reason to expect moral agreement than T does. So ethical disagreement is more probable on N than on T.
16. Moral Progress and the Lack of Moral Prophets
Not only is there ethical disagreement in modern times, but there is ethical disagreement across different time periods throughout human history. To cite just one example: slavery was once widely considered moral, whereas it is now widely considered massively immoral. Ethical relativists will cite this phenomenon as evidence that morality is relative to culture, while moral objectivists interpret this same fact as evidence of moral progress.
If T is true, why aren’t there “moral prophets” in the sense that they clearly perceive objective moral truths which are ahead of their time, such as someone 2,000 years ago declaring that slavery, misogyny, and homophobia are wrong? Why do we instead observe moral progress? For example, why did much of humanity, for most of human history, believe that slavery was morally acceptable? What possible moral justification could God have for allowing people, on such a massive scale, to have mistaken moral beliefs about so many things?
If we make an analogy between God and human parents, believing in T and moral progress is analogous to a human parent letting children believe that it’s okay to, say, hit other people, until the children grow up to become teenagers, at which point the children “discover” that assault is not so morally acceptable after all. Since a good human parent would never do this, why would a good God do this?
In contrast, if N is true, blind nature is indifferent to whether people have correct moral beliefs.[18] Thus, moral progress and the lack of moral prophets is more likely on N than on T.
17. Nonresistant Nonbelievers
There are people who do not believe that God exists.[19] At least some of those people are “nonresistant” nonbelievers—that is, their nonbelief is “not in any way the result of their own emotional or behavioral opposition towards God or relationship with God or any of the apparent implications of such a relationship.”[20] Such nonbelievers are open to having a relationship with God—in fact, they may even desire it—but are unable to have such a relationship.
Given that human beings exist, the fact that some of them are nonresistant nonbelievers is much more probable on the assumption that N is true (and blind nature is indifferent to religious belief) than on the assumption that T is true (and there exists a perfectly loving God who would ensure that a meaningful relationship was always available to those He loves).
18. Former Believers
As Schellenberg points out, such individuals, “from the perspective of theism, were on the right path when they lost belief. If theism is true, indeed, then these individuals already were in relationship with God and the loss of belief has terminated that relationship.” [21]
19. Lifelong Seekers
Schellenberg defines lifelong seekers are ”individuals who don’t start out in what they consider to be a relationship with God and may not even be explicitly searching for God, but who are trying to find out where they belong and, in their wanderings, are open to finding and being found by a Divine Parent–all without ever achieving their goal. These are individuals who seek but do not find.”[22]
20. Converts to Nontheistic Religions
As Schellenberg puts it, there are individuals who investigate other serious conceptions of the Ultimate and who turn up evidence that produces religious belief in the context of nontheistic religious communities and/or on account of nontheistic religious experiences–and the truth of atheistic claims may be seen to follow by implication.[23]
21. Isolated Nontheists
Here is Schellenberg again: “those who have never been in a position to resist God because they have never so much as had the idea of an all-knowing and all-powerful spiritual being who is separate from a created universe but related to it in love squarely before their minds–individuals who are entirely formed by, and unavoidably live their whole lives within, what must, if God exists, be a fundamentally misleading meaning system.”[24]
22. The Geographical Distribution of Theistic Belief
The distribution of theistic belief is uneven around the world. Why does the epistemic or moral defectiveness of non-believers vary dramatically with cultural and national boundaries? For example, why is more than 95% of Saudi Arabia Muslim, while Thailand is 95% Buddhist and only 5% theist? Given the widely held assumption that, generically speaking, epistemic and moral defects are evenly distributed among the world’s peoples, it is hard to see how that question could be answered.[25]
23. The Temporal Distribution of Theistic Belief
Maitzen argues that especially compared to naturalistic explanations, none of the theistic explanations of blameworthy or blameless non-belief accounts for how the global incidence of theistic belief has varied dramatically during the existence of the human species.[26]
24. God’s Silence About His Purpose(s) for Creating Humans
If humankind was created for a purpose by God and had a role to play in carrying out this purpose, then God would want us to have a possibility of achieving our role so that he would have a possibility of achieving His goal. For us to have a possibility of achieving the purpose for which we were created, we would need to understand our role in carrying out this purpose. The purpose for which humanity was created is unclear in the Bible and elsewhere. Despite the lack of clarity regarding the purpose of life, God has not provided any clarification about his purpose or our role. God would not have chosen to remain silent about our role in carrying out his purpose because, following from the first premise, this would be self-defeating. Therefore, humankind was not given a role to play in carrying out a purpose of God.[27]
This may also be categorized as another, more specific fact about divine hiddenness. Why? Despite the lack of clarity regarding the purpose of life, it is antecedently more probable on T than on N that God not only created humans for a purpose, but that humankind would be given a role to play in carrying out that purpose. For the same reason, the lack of any role for humankind to play in carrying out God’s purposes is evidence favoring N over T.
25. The Distribution, Types, and Effects of Religious Experience
Theists will often appeal to religious experience as evidence favoring over N. But the fact that people have religious experiences hardly exhausts what we know about the distribution, types, and effects of those experiences.[28]
First, not everyone has theistic experiences. Given that some people have religious experiences, the fact that not everyone does have such experiences is more likely on N than on T.
Second, those who do have religious experiences almost always have either a prior belief in God or extensive exposure to theistic religion. The distribution of theistic experiences we find is antecedently more likely given N than given T.
Third, the subjects of religious experiences pursue a variety of radically different religious paths, none of which bears abundantly more moral fruit than all of the others. Theism gives us reason to expect that worshiping God is a source of moral strength, a source not available to those who do not worship God, and so T gives us some reason to ‘predict’ that theists would live significantly more moral lives than atheists. The fact, if it is a fact, that no one religious path has produced significantly more moral fruit than another would be more likely if all of these experiences are delusory (which follows from N) than if some or all are genuine revelations from God (and T is true).[29]
So once the evidence about religious experience is fully stated, it’s far from obvious that that it favors T over N.

Notes

[1] Indeed, when properly understood, it becomes clear that neither the Leibnizian nor the kalam versions of the cosmological argument are arguments from the existence of the universe. Rather, the former is an argument from the contingency of the universe and the latter is an argument from the beginning of the universe.
[2] This is based on a brief sketch of an AS in Paul Draper, “Seeking But Not Believing: Confessions of a Practicing Agnostic,” in Daniel Howard-Snyder and Paul K. Moser, eds., Divine Hiddenness: New Essays (New York: Cambridge University Press, 2002), 199-200.
[3] I owe this point to Paul Draper.
[4] Paul Draper, “God and Evil: A Philosophical Inquiry,” 19-20.
[5] Paul Draper, “Evolution and the Problem of Evil” in Philosophy of Religion: An Anthology (3rd ed., ed. Louis Pojman, Wadsworth, 1997), pp. 219-230; cf. Louis P. Pojman, Philosophy of Religion (Mayfield, 2001), chapter 6.
[6] Paul Draper, “Pain and Pleasure: An Evidential Problem for Theists” Nous 23 (3): 331-350 (1989).
[7] Simon Baron-Cohen, The Science of Evil: On Empathy and the Origins of Cruelty (New York: Basic Books, 2012), 16.
[8] Baron-Cohen 2012, 39.
[9] As Baron-Cohen points out, the neurological basis for moral handicaps challenges traditional views about moral responsibility. “If zero degrees of empathy is really a form of neurological disability, to what extent can such an individual who commits a crime be held responsible for what they have done? This gets tangled up with the free will debate, for if zero degrees of empathy leaves an individual to some extent “blind” to the impact of their actions on others’ feelings, then surely they deserve our sympathy rather than punishment.” See Baron-Cohen 2012, 160.
[10] Some theists have pointed out that moral evil, such as fallen angels or demons choosing to do evil, might explain so-called “natural evils.” This argument makes the inverse point: certain natural evils explain at least some moral evil.
[11] Paul Draper, “Darwin’s Argument from Evil” in Scientific Approaches to the Philosophy of Religion (ed. Yujin Nagasawa, New York: Palgrave Macmillan, 2012), 49-70 at 61.
[12] Draper 2012.

[13] Draper 2012.
[14] Draper 2013, 73.
[15] Paul Draper, “Evil and Evolution,” unpublished paper. Cf. J.L. Schellenberg, The Wisdom to Doubt: A Justification of Religious Skepticism (Ithaca: Cornell University Press, 2007), 243-69. Cf. Marilyn McCord Adams, “Horrendous Evils and the Goodness of God” in The Problem of Evil (ed. Marilyn McCord Adams and Robert Merrihew Adams, New York: Oxford University Press, 1990), 209-221.
[16] William Rowe, “The Evidential Argument from Evil: A Second Look,” in The Evidential Argument from Evil (ed. Daniel Howard-Snyder, Indiana University Press, 1996), 276.
[17] Alvin Plantinga, “Epistemic Probability and Evil” in The Evidential Argument from Evil (ed. Daniel Howard-Snyder, Indianapolis: Indiana University Press, 1996), 70.
[18] For the sake of simplicity, I am using “moral beliefs” as a catch-all phrase to include beliefs about both ethical and non-ethical propositions, and so “moral progress” over time  includes correcting past, mistaken beliefs of both types.
[19] This sentence, of course, assumes that at least some (if not most) professions of atheism are genuine. Those familiar with intra-Christian debates on apologetic methodologies will notice that I have just ruled out the claim of some (or all?) presuppositionalists, namely, that there are no atheists and instead there are only professed atheists. I agree with  John Schellenberg: “it would take something like willful blindness to fail to affirm that not all nonbelief is the product of willful blindness (even if some of it is).” See J.L. Schellenberg, “What Divine Hiddenness Reveals, or How Weak Theistic Evidence is Strong Atheistic Proof” God or Blind Nature? Philosophers Debate the Evidence (http://infidels.org/library/modern/john_schellenberg/hidden.html), 2008.
[20] Schellenberg 2008.
[21] Schellenberg 2007, 229.
[22] Schellenberg 2007, 233.
[23] Schellenberg 2007, 236.
[24] Schellenberg 2007, 238.
[25] Stephen Maitzen, “Divine Hiddenness and the Demographics of Theism” Religious Studies 42 (2006): 177-91.
[26] Maitzen 2006.
[27] Brook Alan Trisel, “God’s Silence as an Epistemological Concern” The Philosophical Forum, 43 (2012): 383–393.
[28] Paul Draper, “God and Perceptual Evidence” International Journal for Philosophy of Religion 32 (1992): 149-65.
[29] Paul Draper used this argument in a debate with William Lane Craig on the existence of God, but he now believes that there is insufficient sociological evidence to prove that theists do not live more moral lives than atheists. I have chosen to follow Draper’s lead, so I have presented this point tentatively.

bookmark_borderIndex: Draper’s Evidential Argument from Pain and Pleasure

The purpose of this page is to provide an index for my blog series on Paul Draper’s classic 1989 article defending an evidential argument from evil which focuses on the biological role (and apparent moral randomness) of pain and pleasure.

  • Part 1: summarizes key terminology for the argument, as well as the argument itself.
  • Part 2: summarizes the first part of Draper’s argument, which purports to show that facts about pain and pleasure are more probable on the hypothesis of indifference (HI) than on theism (T).
  • Part 3: summarizes Draper’s refutation of three theodicies which might be used to defeat the first half of his argument
  • Part 4: summarizes Draper’s own views on the evidential significance of his argument, as well as reasons for thinking it will be very difficult for theists to offset the evidence about pain and pleasure.

See also:

bookmark_borderDraper on Pain and Pleasure: Part 4

This post is part of a series on Paul Draper’s classic version of the evidential argument from evil. In the previous entry, I summarized Draper’s refutation of three theodicies which might be used as an objection to the claim that HI explains the facts about the biological role of pain and pleasure much better than T does. In this post, I’m going to review the final section of Draper’s classic 1989 article on the evidential argument from evil.
1. Darwin’s Argument from Evil
In the final section of his paper, Draper sets up an analogy between Darwin’s evidential argument against special creationism and Draper’s evidential argument against theism. It is worth quoting Draper’s remarks about Darwin’s argument in full.

“Darwin argued that his theory of the evolution of species by means of natural selection explains numerous facts (e.g., the geographical distribution of species and the existence of atrophied organs in animals) much better than the alternative hypothesis that each species of plant and animal was independently created by God. (Let us call this latter hypothesis “special creationism.”) Darwin’s results were significant partly because special creationists at Darwin’s time did not have nor were they able to obtain evidence favoring special creationism over evolution theory that outweighed or at least offset Darwin’s evidence favoring evolution theory over special creationism. For this reason, many theists, while continuing to believe in creationism, which is consistent with Darwin’s theory, rejected special creationism. And those theists who were familiar with Darwin’s arguments and yet remained special creationists did so at a cost: their belief in special creationism was no longer an epistemically rational one.”

Draper says that the significance of his evidential argument from evil is to be determined in an analogous way, viz., it depends upon whether theists have evidence favoring T over HI, evidence which could offset his evidence O favoring HI over T. (N.B. Draper points out this evidence could be propositional evidence, non-propositional evidence, or both.) If a theist confronted with his argument lacks and cannot find such offsetting evidence, Draper argues, the theist “cannot rationally continue to believe that theism is true.”
2. Prospects for Theistic Offsetting Evidence
Draper then offers four reasons for doubting the theist will be able to find such offsetting evidence. It is interesting to compare those reasons (offered in 1989) with the positions Draper has adopted later in his career.
(1) In his 1989 paper, Draper claims that it is “doubtful that it could be shown that HI is ad hoc or that T is intrinsically more probable than HI.” It is noteworthy that, long after his 1989 paper, Draper finally started developing his new theory of epistemic probability. When that theory of epistemic probability is applied to HI and T, it yields the result that the intrinsic probability of HI is significantly greater than T.
(2) Next, Draper argued in 1989 that “Traditional and contemporary arguments for theism are far from compelling.” Since 1989, Draper has gone on record as stating that several facts are evidence favoring T over naturalism (which entails HI). Indeed, he even published a paper arguing that the argument from moral agency is “in the same league” as his evidential argument from evil. But Draper also usefully identified a new fallacy of inductive reasoning he calls the “fallacy of understated evidence.” According to Draper, many (most?) evidential arguments for theism, including his own argument from moral agency, commit the fallacy of understated evidence.
(3) Draper’s third reason (in 1989) for thinking that the theist’s search for offsetting evidence will be difficult is this.

Many traditional and contemporary arguments for theism … may not solve the theist’s position even if they are sound and recognized by the theist to be so. For they at most purport to show that an omnipotent and omniscient being exists–not that the being is morally perfect.”

This point seems (to this writer) as true in 2014 as it was in 1989.
(4) Finally, Draper argues (in 1989) that religious experience doesn’t solve the problem identified in (3): “Religious experience is ambiguous with respect to the moral attributes of the creator.” Furthermore, he notes that theistic justification derived from theistic experiences is offset by atheistic justification derived from “experiences of indifference.” Not only is this yet another example of the fallacy of understated evidence, but Draper wrote an article in 1992 on the evidential value of religious experience. In that article, Draper concluded that three specific facts about religious experience favor atheism over T.

bookmark_borderDraper on Pain and Pleasure: Part 3

This post is part of a series on Paul Draper’s classic version of the evidential argument from evil. In the previous entry, I summarized Draper’s first argument, which attempts to show that certain facts about the types, quantity, and distribution of pain and pleasure (P&P) are much more probable on the hypothesis of indifference (HI) than on theism (T), and so constitute strong evidence against T and for HI. In this entry, I summarize Draper’s discussion of theistic explanations for those facts.

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1. “Theodicies” and Theistic Explanations for Facts about Good and Evil
As Draper observes, “Explaining some phenomenon in terms of a statement usually involves adding other statements to that statement.” The relevance to the problem of evil is obvious: people who offer a theistic explanation for facts about good and evil add to T (the proposition that God exists) some additional statement Tn (the proposition that God must allow certain evils in order to achieve some goal).In the philosophy of religion, such additional statements are called “theodicies.” In inductive logic, additional statements of this sort are generically called ‘auxiliary hypotheses.’ In Draper’s terminology, he refers to them as “expansions.”

expansion statement: “a statement h* is an ‘expansion’ of a statement h just in case h* is known to entail h. (Notice that h* can be an expansion of h even if it is logically equivalent to h.)”

With this in mind, consider’s the second part of Draper’s evidential argument from evil again.

A. O is known to be true.
B. T is not much more probable intrinsically than HI.
C. Pr(O/HI) >! Pr(O/T).
So, D. Other evidence held equal, T is probably false.

Draper argues that if a theodicy is to successfully defeat an argument from evil against theism, it must somehow undermine premise (C) by raising the value of Pr(O / T). In order to evaluate whether an expansion Tn of theism raises Pr(O / T) enough to defeat (C), Draper proposes that we use the “Weighted Average Principle” (WAP):
Pr(O / T) = Pr(O / Tn) x Pr(Tn / T) + Pr(O / ~Tn) x Pr(~Tn / T).
As Draper points out, this formula is an average because Pr(Tn / T) + Pr(~Tn / T) = 1. It is not a simple straight average, however, since those two values may not equal 1/2; that is why it is a weighted average. The higher Pr(Tn / T), the closer Pr(O / T) will be to Pr(O / Tn & T); similarly, the higher Pr(~Tn / T), the closer Pr(O / T) will be to Pr(O / T & ~Tn).
Draper states that the second part of his evidential argument from evil assumes that theodicies do not “significantly raise” Pr(O / T) and so the argument effectively treats Pr(O / T) as roughly equal with Pr(O / T & ~Tn). In order to show that this assumption is justified, he says he needs to show that Pr(O / Tn) is “not significantly greater” than Pr(O / T & ~Tn). As he puts it:

In other words, I would need to show that, independent of the observations and testimony O reports, we have little or no more reason on Tn than we have on theism ~Tn to believe that O is true.

In his 1989 article, Draper considers three theodicies:
T1: The Free Will Theodicy, version 1;
T2: The Free Will Theodicy, version 2; and
T3: The Human Ignorance Theodicy.
(Note that while the T1 – T3 notation is Draper’s, the titles of T1 – T3 are mine.)
Before we can discuss T1 and T2, we first need to define a key term:

freedom*: “An action is free* only if
(i) it is free in an incompatibilist sense–that is, in a sense incompatible with its being determined by antecedent conditions outside the agent’s control–and
(ii) if it is morally right, then at least one alternative action that is open in an incompatibilist sense to the agent is such that it would be morally wrong for the agent to perform that alternative action.”

Both T1 and T2 agree that God endows humans with freedom*. They offer contradictory explanations for the existence of pain, however. According to T1, “God permits pain in order to advance morality.” In contrast, T2 explains pain by adding to T a statement about how one of God’s goals is to “increase the responsibility humans have for their own well-being and the well-being of others and thereby increase the importance of the moral decisions humans make.”
Let’s turn to Draper’s objections to each of these expansions of T.
2. “Free Will and the Advancement of Morality”
Let T1 stand for the following expansion of T:

God exists, and one of his final ends is a favorable balance of freely* performed right actions over wrong actions.

Draper begins his response to T1 by making a very charitable concession to the theodicist. He grants, for the sake of argument, that Pr(T1 / T) is high. In order to defend (C) against T1, his strategy instead is to show that:

Pr(T1 / T) is not much greater than Pr(O / T & ~T1).

I interpret Draper’s 1989 article as offering two reasons to believe that.
First, Draper argues that T1 provides a reason we do not have on T & ~T1 to expect that “the world will contain both pain that influences humans to perfom morally right action and pain that is logically necessary for some of the right actions humans perform.” As Draper points out, “O reports the existence of pain of both these sorts,” so those predictions of T1 are confirmed.
But O also reports other facts which T1 predicts should not be true. O also reports both:
(a) that pain often influences humans to perform morally wrong actions; and
(b) that pain is logically necessary for many of the wrong actions humans perform.
Draper concludes that the combination of (a) & (b) is more surprising on the assumption that T1 is true than on the assumption that T is true and T1 is false.
Second, Draper argues that “the world does not contain a very impressive balance of right over wrong actions performed by humans and that this is due in part both to a variety of demoralizing conditions like illness, poverty, and ignorance, and to the absence of conditions that tend to promote morality.” He concludes, accordingly, that this (balance of right over wrong actions) is more surprising on the assumption that T1 is true than on the assumption that T is true and T1 is false.
APP-T1
3. “Free Will and Responsibility”
Let T2 stand for the following expansion of T:

T2: God exists, and one of His final ends is for humans to have the freedom* to make very important moral decisions.

Again, Draper assumes for the sake of argument that the antecedent probability of this theodicy is high, viz., Pr(T2 / T) is high. Again, his strategy is to show:

Pr(O / T2) is not >! Pr(O / T & ~T2)

Draper points out that, “assuming there is no better way,” T2 may provide us with a reason that we do not have on T & ~T2 to expect “the existence of pain for which humans are morally responsible.” But, he argues, Pr(O / T2) is not >! Pr(O / T & ~T2) since other facts O reports are even more surprising on T2 than they are on T & ~T2.
First, “Many humans are plainly not worthy of the freedom* to do serious evils.” On the assumption that T2 is true, however, we would predict that humans would only be given great responsibility when they are worthy of it.
Second, “Nor is the human race making any significant amount of moral progress.” If T2 were true, however, we would expect that humans would be “benefitted by having such responsibility.”
Third, there have been (and are) humans who had (or have) great responsibility, who have abused that responsibility, and did not have their responsibility decreased by God “until they are worthy of a second chance.” But if T2 were true, that is what we would expect.
Draper concludes, accordingly, that Pr(O / T2) is not significantly greater than Pr(O / T & ~T2).
APP-T2
4. The Human Ignorance Theodicy
Here is T3:

T3: God exists and has a vast amount of knowledge about good and evil and how they are related that humans do not have.

Unlike T1 and T2 where Draper granted for the sake of argument that they were antecedently very probable on T, Draper does not make such a concession for T3. It isn’t necessary. As Draper correctly states, Pr(T3 / T) = 1. This, in turn, entails that Pr(O / T) = Pr(O / T3).
But, as Draper argues, T3 fails to defeat O because

We have no more antecedent reason to expect that [God’s additional knowledge is such that he would permit any of the facts O reports to obtain], than to expect that God would have unknown reasons for preventing evil.

Observant readers will notice that the sentence just quoted just is an application of WAP to the idea that God has unknown reasons for his actions.
Furthermore, however much reason we might have on T3 to expect humans would be “unable to product a plausible theistic explanation” for the facts O reports, we have “even more reason” on  HI to expect this. Thus, T3 does not significantly raise the value of Pr(O / T).
APP-T3

bookmark_borderDraper on Pain and Pleasure: Part 2

This post is part of a series on Paul Draper’s classic version of the evidential argument from evil. In the previous entry, I explained Draper’s terminology and summarized the logical form of Draper’s two arguments. In this entry, I focus on Draper’s first argument, which attempts to show that known facts about the biological role of pain and pleasure are much more probable on the hypothesis of indifference than on the hypothesis of theism.
1. Background Knowledge
Like all abductive arguments, background knowledge plays a crucial role in Draper’s evidential argument from evil. Draper’s formulation suppresses reference to background knowledge, i.e., his probability notation does not explicitly contain a symbol to represent the propositions which constitute the relevant background knowledge. In the interest of clarity, however, I’m going to reformulate Draper’s argument so as to explicitly identify the role of those propositions. If we let “B” stand for our background knowledge, then Draper’s first argument may be restated as follows.

(1′) Pr(O1/HI & B) >! Pr(O1/T & B)
(2′) Pr(O2/HI & O1 & B) > Pr(O2/T & O1 & B)
(3′) Pr(O3/HI & O1 & O2 & B) >! Pr(O3/T & O1 & O2 & B)
————————————————————————-
(4′) Therefore, Pr(O/HI & B) >! Pr(O/T & B). (from 1, 2, and 3)

As I interpret him, the following propositions constitute the relevant background knowledge B.
B1: Pain and pleasure, if they exist, have intrinsic moral value.
B2: A physical universe–which operates according to natural laws, is intelligible, and which supports the possibility of intelligent life–exists.
B3: Living things, including sentient beings, exist on Earth. These sentient beings include, but are not limited to, human beings.
B4: Some (Earthly) sentient beings are not moral agents but are biologically very similar to embodied moral agents.
B5: Humans are goal-directed organic systems, composed of parts that systematically contribute to the biological goals of these systems.
2. Draper’s Defense of Premise (1′): Pr(O1 / HI & B) !> Pr(O1 / T & B)
B5 gives us some antecedent reason to expect that pain and pleasure (P&P), if they exist, will also systematically contribute to those goals, just as O1 reports. But, as B1 reports, notice that, unlike other parts of organic systems, P&P have intrinsic moral value: “pain is intrinsically bad and pleasure is intrinsic good.” This difference (hereafter, “moral difference”) between P&P and other organic systems is crucial to Draper’s argument.
First. consider HI. On HI & B, Draper argues this moral difference gives us no reason at all to be surprised by O1. HI entails that, if P&P exist, then they are not the result of “malevolent or benevolent” supernatural persons. Therefore, on HI, the moral difference between P&P and other parts of organic systems provides no reason whatsoever to predict that P&P “will not play the same biological role that other parts of organic systems play.” In other words, blind nature is indifferent to moral value.
Second, consider T. On T & B, Draper argues this moral difference does gives us good reason to predict that O1 is false. T entails that, if P&P exist, God is responsible for their existence. Since God is morally perfect, He would have good reasons for producing pleasure even if it is never biologically useful, and He would not permit pain unless He had, not just a biological reason, but also a morally sufficient reason to do so. Furthermore, since God is omnipotent and omniscient, He could create goal-directed organic systems (including humans) without biologically useful P&P. So T entails both:
(a) that “God does not need biologically useful P&P to produce human goal-directed organic systems;” and
(b) “that, if human P&P exist, then God has good moral reasons for producing them, reasons that … might be inconsistent with P&P contributing to the biological goals of those systems.”
Thus, we have much less antecedent reason on T & B than on HI & B “to be surprised if it turned out that human P&P differed from other parts of organic systems by not systematically contributing to the biological goals of those systems.” In other words, Pr(O1 / HI & B) !> Pr(O1 / T & B).
APP-arg2-1
3. Draper’s Defense of Premise (2′): Pr(O2 / HI & O1 & B) > Pr(O2 / T & O1 & B)
Here is Draper on O2:

O2 reports the observations and testimony reported by O about sentient beings that are not moral agents (e.g., young human children and nonhuman animals) experiencing pain or pleasure that we know to be biologically useful.

Draper’s defense of (2′) is based upon the insight of B4. For the convenience of the reader, I’ll state it again:
B4: Some (Earthly) sentient beings are not moral agents but are biologically very similar to embodied moral agents.
Since O1 implies that moral agents experience biologically useful P&P, HI & O1 & B makes it likely that some sentient beings that are not moral agents will also experience biologically useful P&P. But the corresponding, parallel claim about T is not true: T & O1 & B do not make O2 just as likely HI & O1 & B do. Given T & O1, “we have reasons to believe that God permits the pain O1 reports because it plays some sort of (presently indiscernible) moral role in the lives of the humans that experience it. But the pain O2 reports cannot play such a role, since the subjects of it [hereafter, ‘moral patients’] are not moral agents.”
The distinction between moral agents and moral patients isn’t relevant to Pr(O2 / HI & O1 & B), but it is relevant to Pr(O1 / T & O1 & B). This distinction gives us some reason on T & O1 & B to expect that “the good reasons God has for permitting moral agents to experience pain and pleasure do not apply to moral patients.” This, in turn, gives us some reason to believe that God will not permit such beings to experience pain.
APP-arg2-2
4. Draper’s Defense of Premise (3′): Pr(O3 / HI & O1 & O2 & B) !> Pr(O3 / T & O1 & & O2 & B)
Finally, let’s turn to (3′). Let’s begin by quoting what Draper has to say about O3 and then introduce some more terminology. Here is Draper on O3:

O3 reports facts about sentient beings experiencing pain or pleasure that we do not know to be biologically useful. This includes much pain and pleasure that we know to be biologically gratuitous, as well as some that is not known to be useful and is also not known to be gratuitous.

And here is the terminology.

pathological P&P: P&P that results from the failure of some organic system to function properly, i.e., pain caused by terminal cancer.
biologically appropriate P&P: P&P that occurs in a situation which is such that it is biologically useful that pain or pleasure is felt in situations of that sort.
biologically gratuitous P&P: P&P that occurs in a situation which is such that it is biologically useful that pain or pleasure is felt in situations of this sort, i.e., pain felt by a person killed in a fire is not biologically useful, but it is biologically appropriate because it is biologically useful that humans feel pain when they come in contact with fire.

Let’s move onto Draper’s defense of (3′). He offers a two-part argument in support.
First, he argues, we have much more reason to expect sentient beings, especially nonhuman animals, to be happy given T & O1 & O2 & B than given HI & O1 & O2 & B. Why? We find that many humans and animals experience prolonged and intense suffering and a much greater number are far from happy. Also, we have more reason on T & O1 & O2 & B than on HI & O1 & O2 & B to expect a close connection between moral goods and biologically gratuitous P&P. But we discover no such connection.
Second, Draper observes that we have much more reason on HI & O1 & O2 & B than on T & O1 & O2 & B to believe that the fundamental role of pain and pleasure is biological and that biologically gratuitous P&P is “a biological accident resulting from nature’s or an indifferent creator’s failure to ‘fine tune’ organic systems.” This is supported by O3: much of the P&P reported by O3 is “either pathological or biologically appropriate, while very little is known to be both non-pathological and biologically inappropriate.” “This is exactly what we would expect if P&P are fundamentally biological rather than moral phenomena.”

APP-arg2-3

5. The Deduction of (4′) from (1′) – (3′)
I have saved this section for last since it is uncontroversial. Why is it uncontroversial? Because if (1′) – (3′) are true, (4′) has to be true. This is easier to see graphically, so I’ll start with a graphic and then prove the result.

APP-arg2-5

Here is the proof:
Pr(O / h) = P(O1 & O2 & O3 / h) [logical equivalence]
By the chain rule, we know that Pr(O / h) = Pr(O1 / h) x Pr(O2 / O1 & h) x Pr(O3 / O2 & O1 & h). But, just for fun, let’s derive the chain result anyway.
Let X = O2 & O3 and let Y = O1
Pr(O / h) = Pr(X & Y/ h) [definition of X and Y]
Pr(O / h) = Pr(X / Y & h) x Pr(Y / h) [product rule]
Pr(O / h) = Pr(X / O1 & h) x Pr(O1 / h) [definition of Y]
Pr(O / h) = Pr(O2 & O3 / O1 & h) x Pr(O1 / h) [ definition of X]
Let D = O3 and E = O2
Pr(O / h) = Pr(E & D / O1 & h) x Pr(O1 / h) [definition of D and E]
Pr(O / h) = Pr(D / E & O1 & h) x Pr (E / O1 & h) x Pr(O1 / h) [definition of conditional probability]
Pr(O / h) = Pr (O3 / O2 & O1 & h) x Pr(O2 / O1 & h) x Pr(O1 / h) [definition of D and E]
Pr(O / h) = Pr(O1 / h) x Pr(O2 / O1 & h) x Pr(O3 / O2 & O1 & h)
Using this application of the chain rule, we get:
Pr(O/HI) = Pr(O1/HI) x Pr(O2/O1 & HI) x Pr(O3/O1 & O2 & HI)
Pr(O/T) = Pr(O1/T) x Pr(O2/O1 & T) x Pr(O3/O1 & O2 & T)
At this point it follows axiomatically that Pr(O / HI) >! Pr (O / T) just in case the ratio of each multiplicand on the right-hand side of the equation is greater than one and at least one of those ratios is much greater than one. That is exactly what (1′) – (3′) show:

  • (1′) shows that the first multiplicand for HI is much greater than the first multiplicand for T;
  • (2′) shows that the second multiplicand for HI is greater than the second multiplicand for T; and
  • (3′) shows that the third multiplicand for HI is much greater than the third multiplicand for T.

Thus, if (1′) – (3′) are true, (4′) must be true: Pr(O / HI) must be much greater than Pr(O / T).
 

bookmark_borderDraper on Pain and Pleasure: Part One

The academic journal Nous published an article by Paul Draper in 1989 on the evidential argument from evil. (The article used to be available online for free but is now only available behind a paywall at JSTOR.) The article is now widely regarded as a ‘classic’ in the contemporary literature on the problem of evil; it has been republished in numerous anthologies and readers.
In this part, I’ll summarize the terminology he uses and provide a basic overview of the argument’s logical structure or form. Note that, unless otherwise indicated, all quotations inside quotation marks (“) are quotations of Draper’s article.
1. Terminology, Symbols, and Key Concepts
Before we begin, we need to be clear on how Draper uses the key terminology in his argument.

hypothesis: a proposition which we do not know with certainty to be true or false
theism (T): the hypothesis that “there exists an omnipotent, omniscient, and morally perfect person who created the Universe.”
hypothesis of indifference (HI): the proposition that neither the nature nor the condition of sentient beings on earth results from benevolent or malevolent actions performed by supernatural persons.” Note that HI is logically consistent with both supernaturalism and naturalism. Furthermore, note that HI is logically incompatible with T.
goal-directed: “a system S is ‘goal-directed’ just in case some property G that S has exhibited or will exhibit, a broad range of potential environmental changes are such that:
(i) if they occurred at a time when S is exhibiting G and no compensating changes took place in the parts of S, then S would cease to exhibit G and never exhibit G again,
(ii) if they occurred at t a time when S is exhibiting G, then compensating changes would take place in the parts of S, resulting in either S’s continuing to exhibit G or in S’s exhibiting G once again.”
biological goals: “the goals to which organic systems are directed.”
biologically useful: “a part of some goal-directed organic system S is ‘biologically useful’ just in case:
(i) it causally contributes to one of S’s biological goals (or to one of the biological goals of some other goal-directed organic system of which it is a part), and
(ii) its doing so is not biologically accidental.”
biologically gratuitous: pain and pleasure that is not biologically useful.
O: a statement about “the kinds, amounts, and distribution of pain and pleasure in the world.” O is the conjunction (combination) of the following statements:
O1: a statement about facts about “moral agents experiencing pain or pleasure that we know to be biologically useful;”
O2: a statement about facts about “sentient beings that are not moral agents experiencing pain or pleasure that we know to be biologically useful;” and
O3: a statement about facts about “sentient beings experiencing pain or pleasure that we do not know to be biologically useful.”
“>!”: much greater than
epistemic probability: “Relative to K, p is epistemically more probable than Q, where K is an epistemic situation and p and q are propositions, just in case any fully rational person in K would have a higher degree of belief in p than in q.” Note that epistemic probabilities can “vary from person to person and from time to time, since different persons can be in different epistemic situations at the same time and the same person can be in different epistemic situations at different times.”
Pr(x): the epistemic probability of X.
Pr(x | y): the epistemic probability of x conditional upon y, viz., the epistemic probability that proposition X is true, on the assumption that proposition y is true.

2. The Argument’s Logical Structure 
Draper’s 1989 classic article really has two arguments, which I will summarize in reverse order. The second argument is his evidential argument from evil. That argument is the argument where he argues that the biological role of pain and pleasure is prima facie evidence against theism. Draper did not explicitly state the logical form of his argument in his 1989 article, but he did in a later article. He states the argument as follows.

A. O is known to be true.
B. T is not much more probable intrinsically than HI.
C. Pr(O/HI) >! Pr(O/T).
So, D. Other evidence held equal, T is probably false.

APP-arg2
Note that while the above argument implies that we have a good prima facie reason to believe that T is probably false (since T and HI are incompatible), it does not imply that we have a good prima facie reason to believe that HI is true (since T and HI are not jointly exhaustive and so both could be improbable). So the argument from the biological role of pain and pleasure could be more accurately described as an argument against T than as an argument for HI, though of course in some sense it is both.
Let’s turn, then, to Draper’s first argument. Draper’s first argument, which was the focus of his 1989 article, is his argument for the truth of C. Since O is logically equivalent to O1 & O2 & O3, Draper observes that we can use the chain rule to measure the evidential impact of O upon any generic hypothesis h:
Pr(O/h) = Pr(O1 & O2 & O3/h)= Pr(O1/h) x Pr(O2/O1 & h) x Pr(O3/O1 & O2 & h)
By substituting h with “HI” and “T” we get the following statements, respectively:
(a) Pr(O/HI) = Pr(O1/HI) x Pr(O2/O1 & HI) x Pr(O3/O1 & O2 & HI)
(b) Pr(O/T) = Pr(O1/T) x Pr(O2/O1 & T) x Pr(O3/O1 & O2 & T)
Draper’s strategy for showing that Pr(O / HI) is much greater than Pr(O / T) is to show that “each of the multiplicands” on the right-hand side of (a) is “either greater or much greater than the corresponding multiplicand” of (b). Thus, his first argument goes like this.

(1) Pr(O1/HI) >! Pr(O1/T)
(2) Pr(O2/HI & O1) > Pr(O2/T & O1)
(3) Pr(O3/HI & O1 & O2) >! Pr(O3/T & O1 & O2)
————————————————————————-
(4) Therefore, Pr(O/HI) >! Pr(O/T). (from 1, 2, and 3)

APP-arg1
Obviously, to make both arguments in any way compelling, Draper needs to support the premises of both arguments. We’ll look at the support for those premises in future posts.