Tuesday, September 12, 2017

Bad Argument: Physicalism Can't Be True


Victor Reppert has come up with an argument that supposedly proves his contention that mind must precede the physical.  According to him, this argument does not rest on any assumption of the primacy of mind, which is the metaphysical notion that mental phenomena, such as rational thought or morality, can't possibly arise from any purely physical source, and therefore mind must exist at the most fundamental level of reality.  In fact, most people who hold this belief are theists who think that physical reality itself is the product of a mind.  This stands in stark contrast to physicalism, which is the metaphysical notion that physical reality is all there is in our world, and therefore any mental phenomena that exist must be a product of that physical reality.  While Victor's argument assumes neither of these metaphysical positions, it still contains a serious logical fallacy  Here it is, in its entirety:

My argument is an attempt to show, not assume, that minds exist first, on the grounds that if they don't exist first, they cannot emerge. Mental states have to be a complexity-fact about the physical world if physicalism is true. But let's take the claim that "I am Victor Reppert" and the claim "I am Hugo Pelland." It seems perfectly conceivable that there is a world physically identical to this one in which you are me and I am you. If you say that such a world is impossible, you need to prove it, since it is conceivable. There is nothing about the physical world that guarantees that I will be me and you will be you. So physicalism cannot be true. - Reppert

The first thing to note about this is that it equates conceivability with possibility, but doesn't distinguish between logical, physical, and metaphysical possibility.  The difference between metaphysical and physical possibility is that physical possibility is bound by that laws of nature as it exists in our world, while metaphysical possibility is a superset of that which relates to what might exist in some possible world (and logical possibility is a superset of both*).  The thrust of Victor's argument is that if it is possible that mental phenomena are not bound by physical reality, then physicalism can't be true.  Let me try to put it in the form of a syllogism:
1. Self-identity, as in "I am Victor Reppert", is a mental state.
2. Victor can conceive of some possible world that is physically identical to ours, but the mental states are different.
2a. This would be the case where Victor's body has the self-identity of Hugo Pelland, and vice versa.
3. Since he can conceive it, there must be such a possible world - in other words, it is possible that different mental states could occur from the identical physical reality (from 1 and 2).
4. If it is possible that different mental states could occur from the identical physical reality, then physicalism is false.
5. It is possible that different mental states could occur from the identical physical reality (from 3).
6. Therefore, physicalism is false (from 4 and 5).
We can see from statement 3 that Victor is using metaphysical possibility in this syllogism, because he's talking about some conceivable possible world - not the world we live in.  We can then assume that use of the word 'possible' in statements 4 and 5 refers to metaphysical possibility.  But here we run into a problem.  Physicalism would only be false in some possible world where different mental states could result from identical physical states.  If some other possible world exists where that is not the case (ie, identical physical states always produce identical mental states), then physicalism could still be true in that world.

It seems that Victor is equivocating on the meaning of 'possible' (and as a trained philosopher, he should know better), because his conclusion appears to say that physicalism must be false in our world.  In order to eliminate this equivocation, we should replace "it is possible" with "it is possible in some conceivable world" (lines 4 and 5), and we should replace "is false" with "is false in some conceivable world" (lines 4 and 6).  It then becomes clear that the implied statement "physicalism is false in our world" doesn't follow from this argument.  The only thing Victor has shown is that one can conceive of a world where physicalism is false.  But that's not the case in our world.

Victor's statement "There is nothing about the physical world that guarantees that I will be me and you will be you" is not true in this world, because our self-identity is a product of our physical experience.  No two brains can be identical because they would need to have all the same experiences of body, time, and place.  It is physically impossible for two different brains to have an identical set of experiences, and since those experiences have a physical impact on the brain (by modifying neural connections), then each brain must have a unique self-identity that is a direct consequence of its unique experience in the world.  In this world, physical reality guarantees that "I will be me and you will be you".  In this world, there is still no reason to assume that physicalism is false, and Victor's bad argument has done nothing to change that.




*Note: I disagree with this standard model of modality, because I think that logic itself is a manifestation of the physical reality of this world.  If there exists some other world that has different (or perhaps no) laws of nature, then it is not necessarily the case that logic in that world would be the same as our logic, but would instead be a manifestation of that reality, whatever it might be.  The philosophical presumption that our world's logic must hold true in all possible worlds is based on anthropocentric bias.  See my article Where Does logic Come from?

17 comments:

  1. One has to wonder about Victor using such an obviously unsound argument. Does he know that it is unsound but just doesn't care? Or, is he so desperate to prove his point that he lets these flawed arguments delude himself?

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    1. It's pretty surprising, isn't it?

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    2. In answer to your question, it is my opinion that being religious is equivalent to being on love. When someone is in love, the rational faculties are clouded, especially with regard to the object of their love. They don't see their loved one objectively, the way another person would, and they are blind to any faults that would preclude a more rational person from being so attached. Victor displays the same symptoms, as do many religious people.

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  2. Well, it could still be a physicalist world under some slightly different laws, but that's a quibble. Otherwise, I think you got him there, skep .... this time! .....

    ;-)

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  3. There we go, a post for my philosophy elitism! :p

    Victor's argument is obviously flawed for the reasons mentioned. If Victor = x, where x is some physical description, and Hugo = y, where y is some physical description that is distinct from x, then it makes no sense for Victor to think he could be y over x. For the physicalist, at least one like me, it would be like saying there is a possible world where x =/= x. That's not a possible world I'd accept, and I don't see how his situation is even conceivable. From my perspective, Victor is speaking gibberish in saying he could be Hugo and Hugo could be him.

    Is religion like love? When arguments like Victor's there are used, it looks as if Victor is irrationally attached to something and will defend his attachment at any cost.

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    1. I would allow the metaphysical possibility of a world where physicalism is not true. In that case, immaterial souls could simply trade bodies. Of course, this is not thinkable to a physicalist, and it certailny doesn't happen in OUR world. But if we're talking about possible worlds, THAT possible world certainly doesn't preclude another possible world where physicalism is true. I really don't get how Victor thinks his argument has any merit. He really is stuck on his own conception of reality, to the exclusion of any other.

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  4. Ryan, is there a possible (physicalist) world where the signifier "Victor" is pronounced "Hugo?" And all molecular arrangements, the ingrams of memories or whatever, that here access Victor's identity there was access a different person's identity?

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    1. I think the argument shows that matter in itself isn't enough to explain things, but that's not what physicalists claim anyway.....

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    2. I would need to say no. If any world matches ours in exactly the same physical respects (same laws, same origin state), then I'd need to say everything would be the same, even down to how "Victor" is pronounced.

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    3. I think Victor envisions a world that is physically identical, including physical laws, but still has immaterial souls that are not subject to physical laws. Then, it would be possible for souls to switch bodies. I don't really think it's coherent, given what we know, but he doesn't seem to have a problem with it.

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    4. Skep, I think it's coherent even if not true.

      Ryan, I actually meant if we changed the rules a bit. What physicalism is saying isn't "man is matter" (a la Catch 22) but that the "spook in the machine" is made out of or derives from natural forces. I thought that was the mistake with this argument.

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    5. Coherent in what manner? It's not as if we ever see such things, or as if we ever could see such things. The idea of an immaterial soul is sheer fantasy.

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    6. Be that as it may make, it's like saying "Santa Claus is incoherent"...& even fantasies can be coherent...

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    7. By 'coherent' I mean consistent with known physical reality in this case.

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  5. Reppert has it all arse about. He starts with the notion that the natural supervenes the supernatural. To him, as to all religionists, gods, ghosts, souls, minds, disembodied non-corporeal entities, and all things immaterial are the basic building blocks onto which the physical appends. No proof. No evidence. Just theological assertion.

    The trouble with this assertion is that it is complete religious garbage; an explanatory narrative that has absolutely no foundation in any of the countless human investigative and interpretive activities other than theology and mythology, the head and tail of the same coin.

    In a parody of Madonna's hit song, Reppert is the quintessential IMMATERIAL BOY. What Reppert is really saying is AMOUNTS TO THIS.

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