Biologist PZ Myers today fisks Calvinist philosopher Alvin Plantinga’s essay (written last summer) in which Plantinga claims that evolutionary naturalism is not a coherent intellectual position because we can have no confidence that our brains have evolved to reliably discern truth from error, including the truth or error of evolution and naturalism. They seem to be, in relation to one another, in a Catch-22. Our brains, Plantinga argues, if they evolved, have not done so for purposes of accurately discerning truth, but for accurately discerning mates, predators, and prey. His alternative to the brain’s evolution by the pressures of natural selection is to have faith that God has put into us a “divine sense” that accurately perceives truth (especially Truth with a capital “T”). According to Plantinga, just as we have a sense for hearing physical sounds, we also have a sense for hearing and discerning the voice of God and truth. But if we are merely evolved animals, then we cannot rely on our judgments about the truth of things—including whether or not naturalism is a clear way of seeing the world. Thus, if we claim to be evolutionary naturalists, we ought to be driven into a radical epistemic skepticism. So Plantinga writes:
The problem, as several thinkers (C. S. Lewis, for example) have seen, is that naturalism, or evolutionary naturalism, seems to lead to a deep and pervasive skepticism. It leads to the conclusion that our cognitive or belief-producing faculties—memory, perception, logical insight, etc.—are unreliable and cannot be trusted to produce a preponderance of true beliefs over false. Darwin himself had worries along these lines: “With me,” says Darwin, “the horrid doubt always arises whether the convictions of man’s mind, which has been developed from the mind of the lower animals, are of any value or at all trustworthy. Would any one trust in the convictions of a monkey’s mind, if there are any convictions in such a mind?”
Myers’s response to Plantinga, while characteristically obnoxious in places (as Myers is wont to do), nevertheless struck me as at once sharp and practical. It seemed to cut through a lot of Plantinga’s Calvinist theological fog in a way that only a practicing scientist might do:
To which I say… exactly! Brains are not reliable; they’ve been shaped by forces which, as has been clearly said, do not value Truth with a capital T. Scientists are all skeptics who do not trust their perceptions at all; we design experiments to challenge our assumptions, we measure everything multiple times in multiple ways, we get input from many people, we put our ideas out in public for criticism, we repeat experiments and observations over and over. We demand repeated and repeatable confirmation before we accept a conclusion, because our minds are not reliable. We cannot just sit in our office at Notre Dame with a bible and conjure truth out of divine effluent. We need to supplement brains with evidence, which is the piece Plantinga is missing.
The latter part of this quote contains a particularly astute observation: “We need to supplement brains with evidence.” In other words, we need to bolster our theorizing and philosophizing with evidence precisely because our brains, untethered by encounters with the verifiable, are so unreliable and prone to the compounding of errors. Science, scientific methods, and relentless peer review, function, as it were, as the brain’s performance enhancing vitamin supplements or medicinals. They are human extensions of the brain, attempting to correct—or at least ameliorate—its worst imperfections and tendencies to error.
Plantinga, I assume, would argue that Myers bypasses his point, responding in a practical manner to an epistemic philosophical argument. Plantinga would probably reply to Myers that if you cannot trust the evolved human animal brain for accurately identifying truth (because it did not evolve to discover truth, but evolved for sexual selection and survival), then setting the scaffolding of science over-top of it as a corrective does not really solve the philosophical dilemma of how one ultimately concludes, even then, that you’re seeing the world right.
But Plantinga, if this were the direction of his response, would strike me as being driven into his own peculiar brand of unwarranted epistemic skepticism. It would mean that we would have to treat as a living possibility the idea that science does not give us particularly reliable or true information. Quite obviously, to any sane person, it does.
But I also suppose that Plantinga could then counter with this: How does an evolved monkey brain know what’s sane?
In such a bootstrapping epistemic chase-around, I would simply have to throw up my own monkey arms and side (this time) with the practical biologist over the cunning philosopher-theologian.