Materialism/Physicalism is incompatible with our ability to reason

"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."

Huh? I have no idea what he's talking about. He says it's a mistake and then proceeds to separate the physical characteristics from the mental characteristics, which appears to contradict the bolded sentence. There are no separate mental characteristics. There are only mental descriptions of some single kind of physical processes.

~~ Paul
 
"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."

Huh? I have no idea what he's talking about. He says it's a mistake and then proceeds to separate the physical characteristics from the mental characteristics, which appears to contradict the bolded sentence. There are no separate mental characteristics. There are only mental descriptions of some single kind of physical processes.

~~ Paul

He's saying that if you assume a thought just is a set of physical processes the thought itself still doesn't determine the next thought. Under physicalism I have a thought at time T1 because of the past physical conditions. Same with my next thought at time T2.

Similarly, my sense that my logical chain is rationally justified must also be due to past physical conditions rather than due to the contents of my thoughts.

Another way to think of it is if mental events are just descriptions of physical processes we could be able to create a false environment when an organism evolves to think that logically flawed arguments are rationally justified. But if that's the case how do we know that we are not products of such an environment?
 
Paul, what about Feser's 7 point list!

I'm just going to paste it here as ideally it makes for easy reference/quotation, though I do want to note that the argument (IMO at least) holds for any case where the chain of thoughts is actually due to external factors whether they are God's will or the unfolding of Mind @ Large :

1. Materialism holds that thinking consists of nothing more than the transition from one material process in the brain to another in accordance with causal laws (whether these transitions are conceived of in terms of the processing of symbols according to the rules of an algorithm à la computationalism, or on some other model).

2. Material processes have their causal efficacy, including their ability to generate other material processes, only by virtue of their physical properties (i.e. those described by physical science), and not by virtue of any meaning or semantic content that might be associated with them. (For example, punching the symbols “1,” “+,” “1,” and “=” into a calculator will generate the further symbol “2” whether or not we associate the standard arithmetical meanings with these symbols or instead assign to them some eccentric meanings, because the electronic properties of the calculator alone are what determine what symbols get displayed. Similarly, neural processes that are in fact associated with the thought that all men are mortal and the thoughtthat Socrates is a man would still generate the neural process that is in fact associated with the thought that Socrates is mortal even if these neural processes had all been associated with some other meanings instead, because the neurophysiological properties of the processes alone are what determine which further processes get generated.)

3. But one thought can serve as a rational justification of another thought only by virtue of the meaning or semantic content of the thoughts. (For example, it is only because we associate the symbols “1,” “+,” “1,” “=,” and “2” with the standard meanings that “1 + 1 = 2” expresses an arithmetical truth. Similarly, it is only because “All men are mortal,” “Socrates is a man,” and “Socrates is mortal” have the meanings they do that the first two sentences logically entail the third, and only when the neural processes in question are associated with the corresponding thoughts that the first two provide a rational justification for believing the third.)

4. So if materialism is true, then there is nothing about our thought processes that can make one thought a rational justification of another; for their physical and causal relations alone, and not their semantic and logical relations, determine which thought follows which.

5. So if materialism is true, none of our thoughts ever is rationally justified.

6. But this includes the thoughts of materialists themselves.

7. So if materialism is true, then it cannot be rationally justified; the theory undermines itself.

The upshot of this argument is that instantiating causal relations, of whatever sort, does not by itself amount to instantiating logicalrelations; and this is precisely what Popper is getting at in the passage above when he says that “brain mechanisms” or “computer mechanisms” may “differ physically as little as you may specify, yet this difference may be so amplified that the one may operate according to the standards of logic, but not the other.” Hence even if we concede that certain causal processes are necessary conditions for our reasoning logically (which Popper allows insofar as he says that our ability to follow standards of logic is “in some sense connected with, or based upon, physical properties”), they are not sufficientconditions – in which case there can be no (purely) causal explanation of our ability to reason logically.

Step 2 of the argument seems to follow from the standard materialist assumption that whatever happens in the natural world supervenes on what happens at the microphysical level of nature – the level of the basic particles described by physics and the laws governing them – together with the further materialist assumption that meaning or semantic content is not a microphysical property, whatever else the materialist wants to say about it. That this appears to make the meanings of our thoughts “epiphenomenal” or causally irrelevant to what happens in the world is known as “the problem of mental causation.” Of course, the meanings of our thoughts seem to have an effect on what we say and do; in particular, it certainly seems to us that we judge an inference like All men are mortal and Socrates is a man, therefore Socrates is mortal to be rational because of the meanings associated with these words, and would not judge it to be rational if they had some different content. But Popper’s point is that, if materialism is true, then we can have no grounds for believing that what seems to be the case really is the case. Perhaps the inference in question is in fact irrational, while an inference that seems irrational to us, like All men are mortal, and Grandma drives a Buick, therefore robots are stealing my luggage is a paradigm of rational thinking. Perhaps we don’t see this for the same reason the calculator would spit back “2” in response to the sequence “1 +1 =” even if the latter set of symbols expressed the question Does Grandma drive a Buick? and the former expressed the bizarre answer No, robots are stealing my luggage – namely for the reason that only the physical properties of events occurring in both calculators and brains, and not any semantic or logical properties associated with them, determine what effects they will generate.

For this reason Popper claims that materialism tends to reduce the argumentative function of language no less than the descriptive function to the sub-rational expressive and signaling functions, and thereby tends also to “make us blind to the difference between propaganda, verbal intimidation, and rational argument” (The Self and Its Brain, p. 59).
 
He's saying that if you assume a thought just is a set of physical processes the thought itself still doesn't determine the next thought.
Yes it does, because thought = physical processes. They are the same thing.

Under physicalism I have a thought at time T1 because of the past physical conditions. Same with my next thought at time T2.
And almost certainly some randomness, too.

Similarly, my sense that my logical chain is rationally justified must also be due to past physical conditions rather than due to the contents of my thoughts.
Your thoughts are past physical conditions.

Another way to think of it is if mental events are just descriptions of physical processes we could be able to create a false environment when an organism evolves to think that logically flawed arguments are rationally justified. But if that's the case how do we know that we are not products of such an environment?
We don't. However, our behavior has evolved to produce useful results regardless of the underlying physical reality.

I don't think people are really picturing thought = physical process.

~~ Paul
 
I don't understand his point 4. What are these semantic and logical relations that appear to be separate from the physical and causal relations?

~~ Paul

Is this the clue?

I do want to note that the argument (IMO at least) holds for any case where the chain of thoughts is actually due to external factors whether they are God's will or the unfolding of Mind @ Large :
 
Is this the clue?

Yeah, logical chains have to depend on the semantic content of your own thoughts. If the thoughts arise from external sources - whatever they are - the same failure of rational justification occurs.

Of course there is an interesting conundrum....when you use incorrect reasoning you can still feel like you made a rational argument. Later you might read up on logical fallacies and realize your past reasoning was wrong. Yet the feeling of reasoning correctly occurred both times...so does rationality come down to a refinement of intuition?

Plato ponders this in Meno, concluding that learning is a form of remembering - or rather it's anamnesis, the "loss of forgetfulness".
 
Gualtiero Piccinini, one of the authors of "The myth of an afterlife" comments on William Hasker's review of the book:

http://philosophyofbrains.com/2015/12/09/dualism-and-the-afterlife.aspx

Gualtiero Piccinini says


in his review Hasker argues as follows:

If causal closure [of the physical] obtains, then evolutionary epistemology cannot be the explanation for human rationality. The reasoning is simple and compelling. If causal closure is true, then everything that happens in the brain has its complete explanation in prior physical events, no doubt mainly earlier brain-events. But this means that prior mental events play no role in determining the state of a person’s brain — and therefore, they play no role in the organism’s behavior. It follows, furthermore, that mental events and processes are irrelevant to behavior and are thus invisible to natural selection, which can only operate on physical structures and physical behavior. (emphasis original)

The only way that I can make sense of this argument is that Hasker begs the question by assuming that mental events are metaphysically independent of brain events–precisely the kind of claim that Bahar and I refute in our essay.

He refutes it?? That's a laugh! I need to get to writing my review of the "myths of an afterlife" at some point. Actually, I do argue against Gualtiero Piccinini on a different point he makes in that book, although apparently he read it and says he doesn't understand my point! Here.


But anyway, Keith Augustine appears in the comments, and he alerts William Hasker to what Gualtiero Piccinini says, and Hasker joins in the comments too!
 
BTW now I've mentioned Keith Augustine's name, it seems to me to be fairly likely he'll eventually find this thread, and probably sooner rather than later. Gualtiero Piccinini will too, although perhaps not so soon.
 
What do you mean by thoughts arising from external sources?

~~ Paul

If a thought has no genuine causal power in its semantic/logical content, I'd say it arises from external sources.

Another way of saying it is if one's own mental content can be explained completely in terms of some other "stuff" or due to some other causal power.
 
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If a thought has no genuine causal power in its semantic/logical content, I'd say it arises from external sources.
I still don't know what you mean. What is this "semantic/logical content"?

Another way of saying it is if one's own mental content can be explained completely in terms of some other "stuff" or due to some other causal power.
But the physicalist is saying there is no other stuff, because mental content = physical content.

~~ Paul
 
I was talking about Gualtiero Piccinini supposedly refuting the idea that mental events are metaphysically independent of brain events.
Oops, right. I should have said:

I don't know what Piccinini refutes, but Hasker certainly does seem to beg the question. His statement clearly separates mental and physical events.

~~ Paul
 
It remains the case that intentions, desires, plans are not required, the physical explanation all by itself suffices. So if consciousness were wholly absent from the physical world and we were all p-zombies, we would apparently think, and behave precisely the same. But, absent any reasoning, our p-zombies are no more likely to reach true conclusions from their "thinking" than false conclusions.

Yes?
 
Not if intentions = brain processes. Then intentions are just as required as brain processes because they are one and the same. This is like saying that we don't need computation because physical computer processes suffice. Physical computer processes are computation.

Granted, the ultimate explanation of intention might not involve some dualistic notion of intention. However, note that the Theory of Computation is separate from computer processes because computers are not the only means of computation.

~~ Paul
 
Brain processes are like any other physical processes e.g the Earth orbiting the Sun. Physical processes are immutable. But our thoughts have a freedom and can chop and change with our will, as well as our overt behaviour. If our thoughts were like the Earth orbiting the sun, then our thoughts would lack this freedom. But as I explain in my essays, this is incoherent.
 
Brain processes are like any other physical processes e.g the Earth orbiting the Sun. Physical processes are immutable. But our thoughts have a freedom and can chop and change with our will, as well as our overt behaviour. If our thoughts were like the Earth orbiting the sun, then our thoughts would lack this freedom. But as I explain in my essays, this is incoherent.
Can you conceive a coherent explanation of "thoughts"?
 
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