This morning, I wrote up a quick and dirty response to somebody on the internet who said science had ruled out the Christian notion of free will and morality. I started with C.S. Lewis's argument from reason and segued into Alvin Plantinga's evolutionary argument against naturalism. In the last version of Plantinga's argument that I read, which was in his book, Where The Conflict Really Lies, he pushed the argument from epiphenomenalism and dropped all his arguments about the semantic vs. syntactic content of beliefs as well as thought experiments involving tigers, so that's the direction I went as well. This is similar to a post I made: "the supernatural exists," except that there, I went on to argue as if epiphenomenalism did not follow from physicalism.
Without further ado, here's today's post.
Science studies how the physical world operates. If there is anything like spirits, souls, gods, angels, etc., science would have nothing to say about it. And if these beings interacted in the world, that isn't something you'd be able to tell through ordinary scientific experiments or observations because they would be one-off events. And it would be hard to recognize such events even if you observed them directly because they would only appear to be events in the physical world whose causes were unknown.
So science is not incompatible with there being spirits or souls that interact in the brain.
It could be that we have souls that animate our physical bodies and have causal influence over the brain. The only way to rule that out would be to exhaustively map all the causal interactions in the brain over some interval of time in which a mind/brain interaction occurred. If there are gaps in any causal chain, that could be where the soul interacted. Only if there are no gaps can you rule that out. But since we lack the technology to perform such an experiments, it follows that nobody ever has. So it follows that nobody, in science or otherwise, has ever ruled out the notion of a soul interacting in the brain. And that leaves room for free will.
There are problems with the suggestion that all we are is physical stuff without souls. If, as you say, the brain is all there is to account for conscious experience, and if the brain behaves deterministically according to the laws of physics and chemistry, then it would follow that even our beliefs are determined by blind, deterministic, causal interactions. This removes rationality since rationality can only occur when you hold your beliefs for good reasons. But if your beliefs are caused by antecedent conditions plus the laws of physics, then they occur independently of reasons. It follows that any denial of the existence of the soul is self-refuting because if you deny the existence of the soul and say the brain is all there is, you remove any rational basis for holding that belief. It is as much as to admit that the only reason you hold that belief and somebody else holds a different belief is because it just so happens that the chemical reactions in your brain fizzed in one way and the chemical reactions in somebody else's brain fizzed another way. They were both inevitable, and neither belief is held for reasons.
When C.S. Lewis first made this argument several decades ago, Elizabeth Anscombe responded by pointing out that a calculator behaves deterministically yet still arrives at the truth. The problem with this response is that calculators are not rational. They don't "see" or "reason" to the conclusion that 2+2=4. In fact, they have no idea what number they have come up with. They only arrive at the truth because they were programmed to do so by somebody with a mind.
It may be that our brains have been programmed in such a way that it can arrive at true beliefs most of the time, but if you rule out anything spiritual, there's no programmer like there is with a calculator. It would have to have done so through physical processes.
Maybe you could argue that evolution produced brains that come up with mostly true beliefs. Even if that were true, those beliefs still would not be rational any more than a calculator's results are rational. But let's leave that to the side and ponder this question of whether or not evolution could produce brains that come up with mostly true beliefs.
It doesn't seem like it could. Think about it. Let's suppose all our mental experience is the result of physical processes in the brain which happen deterministically according to the laws of physics and chemistry. It would follow that everything we think, feel, believe, desire, and more importantly for my argument, decide, will, choose, etc. emerges deterministically according to underlying blind physical causes. That means the mind is an emergent thing, and the direction of causation only goes in one direction.
What ever physical state your brain is in at any given moment is determined by the previous physical state of the brain, plus any outside causal interactions (especially sensory input). Brain state 1 causes brain state 2, which causes brain state 3, etc. Each of these brain states has a corresponding mental state (the sum total of everything that's going on in the mind at the time). Since the causation only happens at the level of the brain states, the mental states don't have any causal influence over each other or over brain states. There's just nowhere for them to fit into the causal chain since the physical causal chain exhaustively accounts for everything that happens.
That means, as I explained above, that reasoning doesn't actually occur. You don't draw conclusions by thinking thoughts about premises and their logical relationship to each other. You're simply caused to think one thought, then another, then another, and these thoughts are not connected to each other.
But this also means that your will isn't actually engaged when you act. This mental impression we have of acting on a desire or belief, or doing things on purpose, is just an illusion. The brain causes the illusion of willing, but our desires and beliefs do not affect our behavior at all. This is really important because it means that evolution has no way to produce brains that arrive at mostly true beliefs. Let me explain that a little further.
Natural selection works on our behavior. If you behave in such a way that your survive, then that kind of behavior will be selected for. But if your behavior is not being caused by your beliefs and desires, then natural selection is not selecting for true beliefs and desires. You'd think that a person who believed tigers were dangerous and broccoli was healthy would have a better chance of surviving than a person who believed the opposite, but if our beliefs don't influence our behavior, then they can have no survival value. So we should not expect that evolution would produce brains that reliably arrive at truths on the assumption that brains are all that's there.
This undermines the belief that there's no soul because it removes any rational basis for holding the belief. So if you are to suppose that our brains actually do reliably come up with mostly true beliefs, the only way to consistently hold that belief is to suppose that there's a soul that is the seat of the mind or self. That's the only way a mind can have causal influence on the brain, so that's the only way your desires and beliefs can influence your behavior.
And there are lots of other reasons to think we have souls, but not enough room. If we have souls, then our behavior and our beliefs are not solely determined by blind physical processes in the brain, and that leaves room for free will, morality, and rationality.
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