But then how would we have any trust in our reasoning, including that used to support materialism? I suppose eliminativist materialists do something like this. But then they, to my mind rightly, have to spend a lot of time defending themselves against charges of incoherence. 

Jeremy Taylor wrote:

But then how would we have any trust in our reasoning, including that used to support materialism? I suppose eliminativist materialists do something like this. But then they, to my mind rightly, have to spend a lot of time defending themselves against charges of incoherence. 

I think the crux of the matter is that we observe that our mental states usually seem to operate under the laws of logic while the neurophysiological process operates under the physical laws of cause-and-effect. What would you say, however, to this charge:

Well, perhaps what we really call the laws of logic are just the physical laws of cause and effect. Couldn't we view a syllogism in a cause-and-effect framework? Premises 1, along with premise 2, brings about (or causes) the conclusion. Couldn't inference just be seen as a cause-and-effect process? 

Jeremy Taylor wrote:

I'd say that inferences don't seem to operate via physical cause and effect. We might say our grasp of the premises and their logical relations causes us to grasp the conclusion, but it isn't physical cause and effect. Indeed, I'm not sure what that would mean.

Remember, physical cause and effect is contingent, but sound deductive inference is necessary.

Very true. I'm wondering if you could help answer an objection from a recent interlocutor of mine. After I gave him reasons to believe that propositional logic cannot be accounted for by the physical cause and effect of neurological processes, he proceeded to deny the existence of logical reasoning entirely, opting for what he referred to as "human reasoning." Under this view human reasoning rests on a continuum, along with "infant reasoning," "pig reasoning," etc. Human reasoning, in his words, would look like this:

"I think 'fire' is a word that me, you, and other english speakers use to describe certain configurations of space at certain times. I think there are edge cases where some speakers might insist that something is just smouldering while others insist that there is fire. I don't think there is some abstract object called 'fire', or that there's a rule for determining when some configuration of space at some particular time is 'fire'.
So when a person burns themselves on fire, I think they form a memory of the relevant sense data, maybe what it looks like, what the heat radiating off it feels like, what crackling noises they make. And if in the future they encounter some more sense data that matches their memory of fire, they'll be less inclined to stick their hand in it. I think other animals do something similar."

On this view, human reasoning is reduced to sensory input and behavioral output. Fire burns->avoid fire. This is, as the animals do. I suppose he may argue that we just have a more embellished way of reasoning. 

Jeremy Taylor wrote:

Just ask him to recast his point in such a way that he doesn't help himself to any acts of formal reasoning. Whether or not the desire to avoid fire relies on reasoning, the defence of materialism or naturalism (or natural science) certainly does.

Good point, the fire thing is irrelevant and really only shows that humans and animals both have a survival instincts. He also seems to be insistent that I show him a mechanism in my mind that can deduce that "All dogs are mammals, Fido is a dog, therefore Fido is a mammal" is an example of logical reasoning while "All dogs are odkdf, Fido is a dog, therefore Fido is an odkdf" isn't. I think he's trying to show that there's no way for us to determine what is and isn't valid logical reasoning. 

Jeremy Taylor wrote:

If he means the brain he is just begging the question, as a non-materialist doesn't think such reasoning is a brain process. Otherwise, he is simply an irrationalist. In the end, once someone tries to dispense with logic, it probably isn't worth continuing the argument. After all, what good is an argument without logic and valid reasoning, let alone philosophy and science. Tell him to show how he can reconstruct argumentation, science, and philosophy dispensing with formal reasoning and, if he can't, then leave it at that.

You have been tremendous help Jeremy. Do you have any suggested reading, perhaps an online lecture, article, or--if I can ever find the time--a book that addresses the problem of propositional logic on a materialist/eliminativist conception of the mind? I do think that, prima facie, it would seem odd that logical relations could be reducible to physical causal relations--but I'm not completely certain in this.

Last edited by RomanJoe (5/10/2017 1:24 am)