Materialism/Physicalism is incompatible with our ability to reason

This is from a blog entry of mine that can be seen here.

Contemporary wisdom holds that all physical events have entirely physical causes -- causes cashed out in terms of physical processes that we can potentially measure. This includes everything we ever say and do. This might be taken to suggest that our reasoning, our intentions, plans and so on, don't actually do anything.


However, it seems clear to me that our reasoning must have causal powers. It cannot merely be physical processes that have causal powers. Otherwise thinking something through, and reaching an understanding, would be illusory since any conclusion at the end of a chain of reasoning would not be caused by the chain of reasoning itself, but rather by the neural correlates of the chain of reasoning. If this is so then we can have no more reason to think that our reasoning processes will lead to true conclusions, than false conclusions (see my Can consciousness be causally inefficacious? for a more comprehensive defence of this point).




Materialists often agree with this but assert that materialism does not have this consequence. It does not have this consequence because, so they claim, conscious experiences, such as our reasoning processes, are literally identical to physical processes in the brain. If a train of thought is literally identical to some physical processes, and these physical processes have causal powers, then it necessarily follows that the train of thought itself has causal powers too. So we have no problem here.


I beg to differ.

Let's suppose that in the brain we have a physical causal chain:


1. A → B → C → D → E

And we have a mental chain representing a chain of reasoning:

2. a → b → c → d → e

Now, of course, the materialist claims that “A” is identical to “a”, “B” is identical to “B” etc.

But nevertheless, we have 2 different accounts of how A/a progresses to E/e. In "1" we have the interactions of molecules as mathematically described by the laws of physics. In "2" we have a train of reasoning which, when we attain an understanding of something, will have involved rational connections between thoughts.

Now if materialism/physicalism is true, then everything has the ability to be explained in terms of the physical as exemplified in "1". Account "2" is simply not required, since physical laws, which describe physical processes, make no reference to reasoning, nor indeed do they make any reference to intentions, desires, plans, or any other aspect of consciousness. Indeed, reasoning only comes into the picture for a vanishingly small part of the world; namely brain processes, and a minority of brain processes at that. And it is held by materialists that physical laws provide a sufficient explanation for these minority of brain processes just as much as they provide a sufficient explanation for the rest of the Universe.

But it then follows that reasoning something through is causally irrelevant. Hence identifying reasoning, and the rest of our mental life, with physical processes, doesn't allow us to escape an epiphenomenalist position. I regard this as a reductio ad absurdum of materialism.
 
We are assuming that reasoning = brain processes. Therefore it cannot be the case, as stated in the final paragraph, that brain processes are causally relevant but reasoning is not.

You are confusing explanatory irrelevance with causal irrelevance.

~~ Paul
 
No confusion on my part. If our reasoning is causally irrelevant, then this necessitates it is explanatory irrelevant. And if something has no explanatory relevance, then it follows it is causally irrelevant or causally redundant, notwithstanding the fact that it plays a causal role.
 
Our reasoning is not causally irrelevant: It is identical with brain processes that are not causally irrelevant. You assume this in your blog entry.

Causal irrelevance does not follow from explanatory irrelevance; you are equivocating on the definition of irrelevance. A particular conception of a phenomenon is causal (i.e., causally relevant) along with every other equivalent conception, but might be more or less irrelevant to the explanation of the phenomenon. I doubt there is any such conception that is entirely irrelevant to an explanation; it's a spectrum.

~~ Paul
 
Most certainly our reasoning is causally relevant and -- what amounts to the same thing -- equally explanatory relevant. Our reasoning necessarily directs our chains of thoughts.

But materialism entails that only the the interactions of entities, as mathematically described by the laws of physics, have any explanatory role. Whether or not physical events also have a mental description is wholly irrelevant to what happens. So my reasoning qua reasoning is explanatory irrelevant. If reasoning is explanatory irrelevant, then even though it plays a causal role, it might as well not do so since its causal powers is completely fixed by the physical characteristics of the brain processes. And physical processes are deemed to make no appeal to intentionality, purpose, goals etc. But necessarily our thought processes do (see this essay be me). So if reasoning is causally efficacious, then it must be something over and above physical causes. Hence materialism is necessarily incorrect.
 
Hmmmm...I'd agree it shows materialism cannot be rationally justified, but AFAICTell it doesn't show materialism is false?
 
Now you're changing your story. The causal powers of reasoning are equal to those of brain processes since, as you assume, reasoning = brain processes. Whether reasoning is a useful concept to help explain how humans make decisions is entirely up to the neuroscientists doing the explaining. They can use it or not, as long as they don't endow reasoning with some attribute that brain processes don't have or vice versa.

Physical processes can certainly make an appeal to intentionality et al., if we are assuming that those two things are the same thing. Whether that is a useful appeal is a separate issue.

~~ Paul
 
I'm not sure how I'm changing my story. Scientists -- including neuroscientists -- only appeal to the quantitative, that which can be discerned from a 3rd person perspective. So they can make no appeal to reason.


Sciborg_S_Patel, if materialism is true then our reasoning plays no relevant causal role in anything we think. But that's conceptually impossible. Hence materialism is false.
 
I'm not sure how I'm changing my story. Scientists -- including neuroscientists -- only appeal to the quantitative, that which can be discerned from a 3rd person perspective. So they can make no appeal to reason.


Sciborg_S_Patel, if materialism is true then our reasoning plays no relevant causal role in anything we think. But that's conceptually impossible. Hence materialism is false.

Hmmm....not sure?

I've read this argument both in regards to materialism and in regards to natural selection. Both times it seems the conclusion is the elimination of rational ground, rather than falsification?
 
Sure they can make an appeal to reasoning, since reasoning is brain processes. It might be useful to call some subset of brain processes reasoning for purposes of distinguishing it from other processes and to imply what those brain processes are doing.

You're playing with begging the question by insisting they cannot appeal to reasoning. Why not? We agree that there is nothing about reasoning over and above brain processes. If they are not synonyms, then the assumption in your blog post is not actually being made.

~~ Paul
 
Sure they can make an appeal to reasoning, since reasoning is brain processes. It might be useful to call some subset of brain processes reasoning for purposes of distinguishing it from other processes and to imply what those brain processes are doing.

You're playing with begging the question by insisting they cannot appeal to reasoning. Why not? We agree that there is nothing about reasoning over and above brain processes. If they are not synonyms, then the assumption in your blog post is not actually being made.

~~ Paul

Well, at this point I'd be simply repeating myself! I certainly won't convince any materialists with my essay. I never am able to convince them of anything which challenges their materialism. On odd occasions I might convince non-materialists.
 
Are you sure the problem might not be that your demonstration is logically flawed? You need to explain what it means for reasoning to be brain processes and yet have some attributes that are absent from brain processes.

~~ Paul
 
Paul, have you read Sciborg_S_Patel links?`Are their demonstrations equally logically flawed? I confess I need to read them myself. I probably have read Feser's before though. I do read his blog occasionally. I'll read them later on to see if they're essentially the same argument I'm advancing.
 
Same argument from William Hasker from here couched in terms of evolution. Interestingly he addresses specifically your argument. He says:

It is sometimes thought that this problem can be surmounted by adopting mind-body identity theory. If the physical brain-event is also a mental event, then the mental event is after all causally relevant to behavior, and natural selection can operate to select superior mental processes. This however is a mistake. We have, it is proposed, a single event, which has both physical characteristics and mental characteristics. Notice, however, that only the physical characteristics of the event are causally effective. The causal consequences of that event will be those, and only those, that flow from it as determined by physical forces, as recognized by the true laws of physics. The mental characteristics of the event, whatever they may be, have no effect whatever in determining the subsequent behavior.

Of course he just seems to be saying the same as me, but perhaps he explains it better?
 
If it could be shown that brain states originate from randomness then maybe that would help?

For example, a radionuclide either decays or not based on randomness confined to a bell curve. There is no known causal chain that governs this action choice of: to decay or not to decay?. This action might set in motion a causal chain of events (flag a detector to break the vial of poison killing the cat in the box).

Similarly if the seed of a thought has no causal origin other than quantum randomness, it can't be causally linked to prior causal chains and could therefore be considered an independent causal chain leading to independent actions.

One could say that rooting thought processes in fundamental randomness also does not lead us to trust in our rational abilities to lead us to truth. I would have two responses to this. First, we know that consciousness and intention and future and past states can affect quantum randomness, so there could be a feedback loop here of which consciousness (whatever that is) plays a causal role. Second, rationality is not purely about logic, but also about pattern recognition and overlay. Ratio is a fundamental comparison of one thing to another based on mentally imposed boundaries and spaces which form the basis of all pattern. So rationality Could be thought of as a pattern overlay feedback loop that seeks to adjust and refine the subjectively supplied overlay to match the perception of external or "objective" patterns. Whether or not this feedback loop of refining subjective overlay and comparison with subjective perception leads to "truth" depends on whether the end result can predict future states or provide useful or desirable reactions to future states.
 
I can't find it at the moment, but a few months ago there was a paper arguing that irrational decisions were supposedly proportional to quantum randomness. I was not convinced by it, but perhaps it helps accentuate the previous argument?
 
Same argument from William Hasker from here couched in terms of evolution. Interestingly he addresses specifically your argument. He says:



Of course he just seems to be saying the same as me, but perhaps he explains it better?

So are you about to propose some other incredible (incoherent?) property of matter - the ability to interact with some nonmaterial source of reason?
 
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