An Atheist and a Christian Walk into a Bar

by Randal Rauser

  Now, with regard to the issue of evolution, I'm not going to claim that our knowledge of evolution proves atheism, but I am going to claim that it serves as evidence that favors atheism over theism.

  Randal: Since the reader can't see me, let the record reflect that my eyebrows are rising in incredulity.

  Justin: Eyebrow movement noted.

  Specifically, my first claim is that, when we abstract away from our knowledge of the evidence for evolution, evolution turns out to be much more expected on the atheistic hypothesis than on theism. As a result, our knowledge of evolution strongly favors atheism over theism.

  See, given the fact of the existence of varied and complex life, if atheism is true evolution pretty much must be true because, according to what we know, there are no other viable options.

  Randal: Let me flag my disagreement with this point. But finish your argument and I'll come back to my objection later. I don't want to derail you in the middle of your tactical assault.

  Justin: Okay, that's fair. Now, where was I? Oh, yes; I remember.

  So, what about on theism? Well, theism gives us a number of reasons to be surprised that evolution is true that simply don't exist on atheism. First of all, on theism, God could have brought about a variety of creatures in a number of different ways. So, if theism is true, then it's burdened with the fact that God just so happened to choose the one way available on atheism for bringing about complex and varied life: evolution. This is a stunning coincidence.

  Secondly, evolution can only occur with massive amounts of suffering and death. It's important to appreciate the sheer scale of the suffering and death: millions of years’ worth! It's also important to notice that this suffering and death is not just an accidental byproduct of evolution. Rather, it is intrinsic to the system. Given that theism posits a God with moral motivations, theism must say that there exists some justification for all this death and suffering. That is an additional detail that the theistic hypothesis is saddled with, whereas, on atheism, no further detail beyond the fact of evolution is necessary to explain the suffering and death. So that is an additional sense in which atheism enjoys an explanatory advantage over theism with regard to the scientific fact of evolution.

  Randal: Okay, like I said, I want to start off and raise an objection. But, before I do, I'd like you to step back for a moment and say something more about how you are defining evolution, since different readers may have somewhat different concepts in mind.

  Justin: Very true. It's certainly important that I get clear on exactly what is meant by evolution. Here though, I'm going defer to philosopher Paul Draper, the original defender of this argument, so that I don't have to do the work.

  Randal: Paul Draper is here? Awesome! So where is he?

  Justin: Found him! The relevant passage is from Draper's 1997 article, “Evolution and the Problem of Evil”:

  By “evolution,” I mean the conjunction of two theses.

  The first, which I will call “the genealogical thesis,” asserts that evolution did in fact occur—complex life did evolve from relatively simple life. Specifically, it is the view that all multicellular organisms and all (relatively) complex unicellular organisms on earth (both present and past) are the (more or less) gradually modified descendants of a small number of relatively simple unicellular organisms.

  The second thesis, which I will call “the genetic thesis,” addresses the issue of how evolution occurred. It states that all evolutionary change in populations of complex organisms either is or is the result of trans-generational genetic change (or, to be more precise, trans-generational change in nucleic acids).1

  It's important, I think, to notice that Draper is also careful to distinguish that last claim from the much more specific claim that purely unguided (Darwinian) natural selection operating on random mutations is the primary driver of evolutionary change.

  Randal: And why is this distinction important?

  Justin: Well, it's because an evidential argument from evolution against theism that assumed from the start that the primary driver of evolutionary change was purely unguided natural selection (rather than guided selection) acting on random mutation (rather than guided mutation) would be, in a sense, begging the question against the theist who believes that, at the fundamental level, the mutations and selection are indeed guided.

  Randal: Fair enough. I actually don't think that is an issue with using the concept of random mutation, so long as one recognizes that science doesn't deal with metaphysical appeals to God or denials of God. In my view, any scientific appeal to randomness is a separate topic from the providential involvement of any deity in those random processes, since science simply doesn't address theological or supernatural causes. But this point is a potential rabbit trail, so I'm happy to drop it.

  Justin: I see your point. Well, before I move to the second half of my argument regarding the relationships between pain, pleasure, survival, and reproduction, did you have any objection to the first half on evolution?

  Randal: Hmm, yeah, perhaps this is when I should raise the concern I noted above.

  Justin: Ah, yes. I almost forgot. So what was your concern?

  ATHEISTIC ALTERNATIVES TO EVOLUTION?

  Randal: You said that if atheism is true then “evolution pretty much must be true because, according to what we know, there are no other viable options.” And thus, so you said, if it should turn out that theism is true it would be a “stunning coincidence” that life should have originated through the one way consistent with atheism.

  Here's where I must lodge my disagreement. Just because you are not aware of any other explanations for the origin of species consistent with atheism, it doesn't follow that there are no other options.

  Justin: That's a good point. Notice though, that I was careful to cast this argument in epistemic terms. Given the complete lack of viable alternatives, it's highly probable that, if atheism is true, evolution must also be true because we observe the fact that a variety of life does indeed exist.

  Randal: Interesting. But alas, I don't think that follows at all. The history of science is a history of theories at one time confidently held and supported by an abundance of evidence but later overturned. So how do you know that there will not be a completely different theory in fifty years to explain biological diversity?

  Justin: Yes, that is of course possible, and, if the facts were to change, then the argument would have to take on that new information and adjust accordingly. But Randal, this is the case with all evidential arguments on all sides of any debate that appeal to the current state of acquired knowledge.

  From where I stand, this is not so much an objection as it is a reminder to us both of the limits of evidential inferences in general.

  Randal: No, it's an objection. You see, I'm not merely making a general observation about the broadly qualified nature of evidential inferences. Rather, I'm pointing to a past track record of failed scientific theories as justification for skepticism that a current scientific theory will remain the definitive, correct theory. And note, by the way, that this argument precisely parallels your appeal to an (alleged) track record of past failed theological theories as grounds to justify rejecting my theistic explanation of mathematical structure in nature.

  Perhaps I can unpack my point with an illustration. Imagine that you and I are driving a twisty road to a new city. I ask you, “When will we get there?” and you reply, “Just around that next bend!” But as we turn the bend we find no city. Later I ask again, “When will we get there?” and again you reply, “Just around that next bend!” And doggone it, once again you're wrong! This same scenario then plays out several more times. The tenth time you tell me the city is just around the next bend, I'll have a strong undercutting defeater to your testimony. In other words, while you still could be right, given your past track record the rational thing to do is withhold belief.

  That illustration provides a fitting analogue for our current state of knowledge regarding scientific theori
es. Just as your reports of the approaching city continue to be falsified in the analogy, so it is with those who declare that a particular scientific theory has provided the definitive account of a given subject matter. Theories keep getting falsified, radically revised, and just plain abandoned.

  And, just to be clear, my point is not that evolution or any other theory will be falsified. Nor is it even that any particular theory will probably be falsified. Just as the city could be around the next bend so this could be the definitively correct theory. Rather, the point is simply that, from our present standpoint, we simply lack knowledge to render an informed judgment on the question. So, just as I should withhold assent the next time you claim that the city really is around the next corner, given the past track record of scientific theory failure (falsification, abandonment, etc.), we ought to withhold assent in the final correctness of neo-Darwinian evolution. And that, in turn, means that your claim that it is highly probable that evolution will be true if atheism is true is simply unjustified.

  Justin: But Randal, my argument does not assume that evolution will never be falsified. It simply says, given the current state of information, this is what follows. Are you saying that the mere possibility of any scientific consensus being falsified in the future means that we cannot make evidential arguments with “highly probable” conclusions at all?

  Randal: My objection isn't based on the assumption that you believe evolution will never be falsified. Rather, it's based on the claim that, given the past history of theory failure, you lack the ground to make any probable judgments since you simply cannot project on the future course of scientific advance in the coming decades and centuries. Just as a past history of failed reports that the city is around the next bend undermines the present testimonial report that the city is around the next bend, so the past history of scientific theory change on an issue like biological origins undermines the ground to believe that a neo-Darwinian evolutionary account will probably never be replaced or radically revised.

  At this point, Robert Crease and Charles Mann provide a salutary warning when they recount the confident attitude of many physicists at the end of the nineteenth century. According to Crease and Mann, at that time many scientists

  believed that all of physics was already known and that future generations of scientists would only buff and polish the insights of the past. Indeed, the certainty with which many physical scientists of the 1880s thought they had the fundamental puzzles nailed down is today a source of puzzlement to scholars. At Harvard University, for instance, the then-head of the physics department, John Trowbridge, felt compelled to warn bright graduate students away from physics. The essential business of the science is finished, he told them.2

  Then Albert Einstein appeared on the scene and the rest is history.

  Who knows what Einstein might appear tomorrow in physics, geology, or biology to offer astounding new insights that will shake solid paradigms to their foundations? So the simple lesson is that your inference outstrips the evidence you have for it. And this means that you are simply not justified in your claim that evolution will be true if atheism is true.

  Justin: I must admit to being confused by your comments here. This has nothing to do with any future expectations, Randal. Of course our current theoretical framework may be overturned in the future, but that doesn't disallow us from talking about what follows from our best and most current theories.

  Currently, the best explanation for the diversity of life is evolution. Now, if we conditionalize on that fact and if atheism is true, it follows that evolution practically had to be true. And again that is informed by the current state of knowledge and may change. This is true regardless of past changes in scientific consensus. So, contrary to what you've said, my claim here is not to be equated with the claim that it is highly probable that evolution will never be overturned for another theory.

  Randal: No, no, no. Just because you now believe x is a fact it doesn't follow that x practically had to be true. Alas, I fear we're going in circles here. Perhaps I should shift my point of critique. The fact is that there are many theories for the origin of the diversity of life on earth that are consistent with atheism, including presently defunct theories like Lamarckianism, spontaneous generation, and panspermia, as well as countless theories not yet imagined. So I see no rigid connection as you apparently do between the current dominance of neo-Darwinian evolution and the possible truth of atheism.

  That said, I don't want to derail your argument any further. Feel free to proceed when ready.

  Justin: Before I move on, I do want to note that I mentioned a lack of plausible alternatives on atheism for explaining the diversity of life. Special creation is inapplicable for that reason. As for the others, they either are attempts to explain the origin rather than the diversity of life, or they lack a plausible mechanism.

  Randal: Wait a minute. Spontaneous generation is not the same thing as special creation nor does it require theism. Moreover, Lamarckianism explicitly explains diversity and panspermia readily could as well. And as I said, the lack of a current plausible alternative does not warrant the conclusion that there will be no plausible alternative.

  Justin: Yeah, I think I'm going to move on to the latter half of the argument now.

  Randal: By all means.

  NEW AND IMPROVED COMPETITORS

  Justin: For the second half of this chapter, I want to treat the biological fact of evolution (from the first half of this chapter) as an add-on to theism and to atheism. When we add evolution to each of these hypotheses, we get two “extended hypotheses.” Let's call these extended hypotheses “theistic evolution” and “atheistic evolution,” the new and improved competitors.

  Now I want to take these extended hypotheses and compare them as to their ability to explain some interesting facts about the experience of pain and pleasure. In doing so, we will discover the second evidential boost for atheism over theism in this chapter (evolution itself was the first). So, what is this new evidence I wish to consider?

  Randal: You took the words right out of my mouth! What evidence, pray tell?

  Justin: Okay, so, when it comes to the experience of pain (and pleasure), much of it that happens in the world is clearly systematically connected to the biological goals of survival and reproduction.3

  Randal: Slow down buddy. You're tossing out a lot of highfalutin’ concepts here. I think some further explanation will be helpful.

  Justin: Guilty as charged. I suppose an example might help. Philosopher Paul Draper uses the example of how a warm fire on a cold night is something we typically find pleasurable, while lying naked in a snow bank is something we typically find painful. He notes that this is because maintaining a constant and physiologically safe body temperature increases the chances that the organism will survive and reproduce. The biological usefulness of pain perception for an organism's survival becomes even clearer when we see how difficult it can be for those who live completely without pain to stay alive or to avoid serious injury. Of course, pleasure too is often biologically useful. For example, the pleasure we experience during sex increases our chances of engaging in sexual activity and that increases our chances of reproducing.

  Randal: I'd like to pause at the point where you say the reason folks don't like chillin’ in a snow bank is because the maintenance of a safe body temperature increases the chances that they will survive and reproduce. It might help if I give voice to a skeptic. This skeptic happens to be a twenty-year-old snowboarder named Brody who has some familiarity with the practice. So Brody, what do you think about Justin's claim?

  Brody: Dude, the guy is nuts! The reason I don't lie naked in snow banks is because it's painful dude, not because I want to have a brat some day! And believe me bro, I've tried the snow bank plunge. It ain't fun.

  Randal: Thanks for sharing your thoughts, Brody.

  So Justin, what would you say to my incredulous snowboarding friend who balks at your explanation for his behavior?

&nbs
p; Justin: Well, first I'd caution Brody against pulling his bleached tips out over this. Notice that even if Brody as an individual has no interest in having a brat, he still has an interest in the biological goal of surviving. But, really, that's beside the point. It is in fact the case that the bodily systems that cause his experience of pain and pleasure are oriented toward the biological goals of survival and reproduction. He may not intellectually grasp the biological importance of maintaining a constant and safe body temperature, but that doesn't mean that these systems are not the reasons for his experiencing pain.

  Of course, there is another interesting fact about pain and pleasure: not all pain/pleasure is biologically useful. For example, imagine the horrible pain experienced by the family who eventually perishes in a house fire, or the excruciating pain experienced by those with horrible terminal illnesses. Those examples of pain fail to be biologically useful because they do not contribute to biological goals. Pleasure can fail to be biologically useful as well. Consider the pleasure experienced every time the drug addict feeds his crippling addiction.

  If atheistic evolution is true, then we can expect purely natural and blind (Darwinian) processes to be responsible for the existence of pain and pleasure in the world. Atheistic evolution makes it likely that humans, if they exist, will be the goal-oriented organic systems that they actually are. Humans will be composed of parts that are systematically oriented toward biological goals like survival and/or reproduction. If pain and pleasure do exist, we'd expect that they too are systematically oriented toward those biological goals.

  But with theistic evolution things would look very different. On theistic evolution, these facts would be rather surprising.

  Randal: Of course, I'm going to ask you why you think these facts would be surprising on theistic evolution. So, um, why do you think that?