I recently commented on Facebook that we have no ground for trusting in reason on the basis of naturalism. A couple folks asked me to elaborate. The basic line of reasoning is a bit too long for a Facebook comment so I lay it out here.
Arguing that belief in God is necessary for one to believe in the validity of reason would be ambitious for a single blog post, much less a FB comment. Arguing that a concept of god is sufficient for one to do so and that naturalism is insufficient, will be all I’ll try to tackle here.
What is reason? Put simply, reason is the cognitive process by which our minds process information and filter truth from untruth. It consists of a set of intuitions which we understand and agree to be sound. It is intuitive to us, for example, that if A implies B, and B is false, then A is false. This way of describing the relationships between ideas, and the associated intuitions we have about the meaning and implications of ideas, we call reason.
We can imagine, hypothetically, a species of organisms evolving which had no such intuitions – perhaps something like a slug or an amoeba. We might also imagine in our hypothetical world a demi-god (or if you wish to assume naturalism we can say a super-advanced alien) which has a mind so advanced that its species’ way of thinking is infallible. Their cognitive processes are universally applicable, that is to say they are reliable in any context and any field of inquiry. And in any field of inquiry, this being’s way of processing information leads always to the truth when it is properly utilized. Perhaps any individual of the super-alien species might have a sharper or duller mind. Some may utilize their species’ cognitive method with more speed than others. Some may occasionally apply it imperfectly, others may be brighter and misapply it less often than their peers. But if their way of thinking is rightly applied, it is always sure to lead to the truth in any field of thought.
Between these two creatures, the slug and the super alien, we might imagine a range of intermediate creatures with varying cognitive processes of their own. Perhaps one creature has a way of thinking that is crudely useful for a few narrow purposes such as feeding, mating, fighting. A dog or cat, we might say. This creature’s way of cognition will not be totally useless but it will break down, betraying its purpose and leading the creature dangerously astray in some situations. And outside of the narrow context for which it’s cognition developed, this creature’s mental process will not yield useful conclusions. A dog can’t contribute, for example, to the solution to an economics problem. Between our hypothetical super alien and the dog, perhaps we can imagine still another creature, this one moderately advanced, such as a dolphin or a chimpanzee. Their cognitive process is more broadly useful than the dog’s. Adapted to a wider range of contexts. And more reliable in many of those contexts than the dog’s or cat’s would be. But not universally useful as the super alien’s way of thinking is. And not infallibly linked to truth in those areas the way the super alien is.
Imagining all these creatures, we can make an important observation about them. There is a particular chimpanzee’s cognition. But there’s also a generalization we can make, call it “chimp-like cognition”. Any particular chimp exhibits a particular example of “chimp-like thinking”. Perhaps it’s a clever or a dull chimp. It is better or worse at utilizing its “chimp-like” thought process. What can we say about “chimp-like cognition”? First, when two chimps are at odds, they may dispute. This has been observed in captive and wild chimps. We can expect both chimps to act in a dispute on the basis of what we call their “chimp-like” thinking. One may be “better” at it than another. But the failures of “chimp-llike” cognition (those that distinguish chimp cognition from “super-alien” cognition in our hypothetical) will hamper both chimps. Neither will be able to help the other’s inability in these areas. What they both see incorrectly, they will both be helpless to address. What we are calling “chimp-like” thinking, the chimps themselves will think of as we think of “reason”. And they will both be blind to its limitations. Where it leads them astray, they will both be led astray. Likewise with the dog’s way of thinking or the dolphin’s etc. Where doglike cognitive processes or dolphin-like cognitive processes lead them astray, they will be led astray.
But what of human-like cognition; what we ourselves call reason? Perhaps the naturalist is correct and it is something which evolved in order to adapt us to survival and procreation just like the way in which dog, dolphin and chimp cognition developed. If this is the case we would expect what we call reason to be useful, particularly in the context where it evolved and for the purposes we pursued in that context. It’s usefulness may very well be extremely advanced. But we would also expect it to be at best indifferently adapted to other contexts which didn’t exist at that time. And it is a definite possibility that it would be maladapted to certain applications. Where it was maladapted and led us astray, or where it was indifferently adapted and gave us no help, we would not know it. What it taught us we would call truth. What we saw by its light is all we would see. To us it would seem perfectly linked to truth. But we would be mistaken in certain areas. We would look upon this “man-like” way of thinking just as we look upon what is called “reason”. But if it was adapted for survival and procreation on the savanna’s of Africa, we couldn’t also be sure it was adapted for particle physics. Or epistemology. Or ethics. And in those areas of inquiry that it was adapted for, we couldn’t know the extent of its adaptation. Reason may be a way of thinking that is extremely well-adapted, a consistent rule of truth and falsehood. Or it could just be crudely adapted – a coarsely useful but relatively clumsy adaptation. Naturalism tells us nothing about which human attributes are more or less adaptive. Only that none are perfect. In other words, if what we call reason is a mere adaptation then we know at best it usually corresponds to truth. But sometimes doesn’t. And when it doesn’t, we can’t tell.
Another possibility is that what we call reason is like the way of thinking of the super-alien or the demi-god in our hypothetical world – perfectly adapted to every context, and linked to truth absolutely and universally at all times and places. Individuals could exhibit an imperfect example or an imperfect application of the way of thinking. But the method of thinking itself would be infallible. There’s no reason to believe that natural selection would give us this perfect sort of cognitive process. It would in all likelihood give us something less. That kind of perfection does not arise by natural selection. Only coarse adaptive usefulness can be counted on from natural selection. And if you believe that it could produce perfection, certainly anyone can see there is no guarantee that it must.
Perhaps the super-alien intelligence could take steps to impart their universally-applicable and reliably infallible cognitive methodology to us. We could then, perhaps, have a way of thought that is perfect when used correctly. This would be something akin to the theistic account of what reason is.
On the naturalistic account, this level of perfection cannot be relied upon – only a rough and ready usefulness can be reliably counted upon from natural selection. If this rough and ready usefulness, and not perfect correspondence to truth, is all we can count on from reason then we must still live like reason is perfect for pragmatic reasons. But our world-view tells us otherwise. And worse, we can all agree that a certain fact is rational, and that we are being objective about that fact, and it still may be false in spite of being what we call rational. We have to act like that isn’t possible. But without the super-alien or the demi-god type of reason, we haven’t any cause to believe so.