A universal acid is a substance that eats through everything it touches—something incessantly corrupting that cannot be contained. Philosophers like David Dennett have suggested that Darwinism and the theory of evolution are like that. Once entertained, evolution seems to substantially alter—if not fundamentally corrupt—everything it encounters, including our beliefs in God, morality, and human nature. In fact, philosophers of a naturalistic bent have suggested that evolutionary theory should cause us to think there just are no such things as God, objective moral facts, and human essences.
Darwinism is thought to debunk theism (and by extension religion) as follows. Life began in some pre-biotic soup, by chance. Evolution takes hold, and eventually, complex beings emerge, including beings with thoughts and beliefs. Like everything else that sticks around, such thoughts and beliefs are supposed to contribute to survival—which is to say, they cause us to “have sex and avoid bears.” And if some thought or belief contributes to this ennobling cause, it doesn’t have to be true; it could just be useful.
Belief in God is said to be like this. Somehow, somewhere, the fantastic idea popped into our slightly-superior-to-chimpanzee brains that some Cosmic Deity is behind everything, and this contributed to human survival by causing us to behave in more productive and harmonious ways, whatever those are. So that fantastic idea not only stuck around, but spread. Yet it has no basis apart from survival value. Thus, God is a false but useful belief. Destroyed by Darwin’s acid. Too bad, so sad. What’s for dinner?
But why stop with God and religion? Why shouldn’t atheism burn through everything else, too? Some philosophers, like Alvin Plantinga, claim just as much: if naturalism is true, then Darwin’s acid burns through the conditions of knowledge itself. So even if naturalism were true, we could never know it. Thus, Darwin’s acid provides an undefeated (and undefeatable) defeater of naturalism. It can’t be affirmed rationally.
There are objections and rejoinders to Plantinga’s argument. However, simulations in evolutionary theory raise support for it. For example, a research project testing the claim that evolution would favor what our reality actually looks like concluded precisely the opposite: “We find that veridical perceptions can be driven to extinction by non-veridical strategies that are tuned to utility rather than objective reality. This suggests that natural selection need not favor veridical perceptions.” In plain English: Evolution could instill false beliefs even about what you think you are seeing, hearing, etc., just so long as those false beliefs caused you to survive.
To offer a fanciful illustration, consider this: maybe you think you’re playing Mario Kart with your children, but you’re actually avoiding a swarm of crocodiles. What matters for survival isn’t whether your beliefs are true—just that all your joints get into the right position at the right time to avoid the crocodiles. There is little reason to think that requires true belief or even having beliefs at all—or so Plantinga claims. If even our basic experiences are under threat, then Darwin’s acid burns deep.
But in fact, we shouldn’t distrust our basic experiences. Notice that we come to distrust our basic experiences only by relying on them to develop an evolution theory that calls them into question. From there, if we call our basic experience into comprehensive doubt, we lose reason for believing evolutionary theory in the first place.
If we have a universal acid here, it’s atheism plus Darwinism, not evolution itself. Remember: the atheist must accept that evolution has programmed false (but useful) beliefs in us—belief in God being a big one. But theism plus Darwinism wouldn’t invite such ridiculous skepticism, given God’s ordering of natural processes, including evolutionary ones. Thus, if we believe that our faculties are generally reliable (as we must to avoid the self-defeat issue) and that evolutionary theory is true, we can make these commitments compatible (reliable faculties and evolution) by abandoning atheism.
It is difficult to see how Darwin’s acid doesn’t damage morality as well, just as many atheistic thinkers who embrace nihilism contend that it does. Darwin’s acid becomes doubly troublesome when it comes to account not just for the existence of moral facts (that some things are truly right or wrong, good or bad), but also moral knowledge (that we can even know what is right or wrong, good or bad). Atheistic philosophers often deny the existence of moral facts, claiming that ethics is something invented, though other atheists have tried to hold on. Either way, accounting for moral facts is not enough: we must account for moral knowledge of such facts and the process producing it, which seems inherently unreliable if we’re accepting naturalism.
So how do atheists try to keep the universal acid from burning up their morality? Philosopher Sharon Street argues that evolutionary theory should cause naturalists to prefer an “adaptive link account” between survival and moral beliefs, which means embracing some variety of moral anti-realism like constructivism—the idea that we invent morality rather than discover it. Street rejects fitness following universal moral truths as scientifically implausible. It’s far more consistent with evolutionary theory and naturalism generally to go the route of “false but useful” moral beliefs. In short, if you’re an atheist and believe in evolution, the best and simplest theory is to think there just are no moral facts. But is that really right? Is it not a fact to say rape (or genocide) is wrong? Merely a preference, then? Come on!
Atheists who are not ready to abandon objective morality have attempted rejoinders. Of course they have; these implications are not just uncomfortable, but unacceptable—and false. Unfortunately for them, in attempting to contain the acid, they progressively reach for increasingly bizarre and exotic containers, such that it is difficult to call their theories atheistic or naturalistic anymore. (William Lane Craig has labeled them metaphysical voodoo.)
If you’re going to be an atheist, better, I should think, to follow naturalist philosopher Alex Rosenberg, who not only is willing to let Darwin’s acid burn, but encourages it. He writes, “We differ from those who fear Darwinism because we believe it is true. But we do not think that we can or need hide our countenances from the nihilism it underwrites.”
It’s not just atheistic philosophers who conclude that nihilism—the rejection of all meaning, value, purpose, etc.—is the organic outgrowth of atheism plus Darwinism. It is also suggested by Joe Atheist on Twitter, who tells me that morality is all human construct, the product of evolution—ergo, there is nothing real (beyond our heads, anyway) about it. That tells me that the natural (non-contrived) naturalistic expectation is to go with the simpler account of moral beliefs, which is to allow Darwin’s acid to burn away moral beliefs. Other philosophers who realize the indispensability of objective morality (and who happen not to believe in God) do what they can to prevent this. They are unsuccessful, I believe.
Even if not entirely universal, Darwin’s acid, released by atheism, cannot be reasonably contained by making naturalism increasingly exotic. I take this as a good reason to endorse theism.