Here I'll show how an argument similar to Frank Jackson's famous "Knowledge Argument" might be used to show that substance dualism is true.
Let's absolve Mary of her color blindness and introduce Jack, an equally brilliant scientist who has also spent his entire life in a black and white room wherein he has learned everything he knows about science. Jack is color blind and has never experienced, say, redness. Suppose we bring a person, call her Jane, into Jack's room who is to be his subject. Jack will study Jane's brain so that he has complete knowledge of it. Suppose further that Jack succeeds: Jack knows everything about Jane's brain. Now, Jane, whilst in the room, experienced redness. Given that Jack knows everything about Jane's brain, has he too experienced redness? It seems not. Jack might know that she experienced redness, but he wouldn't know what it was like for her to have experienced redness. It is also difficult to see how complete physical knowledge about the brain might produce an experience of redness. Suppose now that Jane has in her mind an image of a magnificent work of art, say, the ceiling of the Sistine Chapel. Given that Jack has complete knowledge of her brain, does he too learn of that image? Again, it seems not. It seems that Jane is the only person who has access to this experience. It also seems odd to suppose that knowing about all of the physical goings on in the brain entails knowing everything about an image one has in their mind. Where in the brain will you find the image of the Sistine Chapel? So I think it is obvious that Jack might know everything about Jane's brain and still be ignorant of some facts about Jane.
And now we have an argument for substance dualism.
(E) For all x and y, if x = y, then, for any person P, P knows everything about x just in case P knows everything about y.
Suppose Jane = her brain, or some part of her brain. That means that, by (E), Jack knows everything about her brain just in case he knows everything about her. Jack knows everything about her brain. Therefore, Jack knows everything about Jane. But, as we have seen, Jack doesn't know everything about Jane. He doesn't have access to her experience of redness or to her image of the Sistine Chapel, which are two obvious facts about her. Since this is a contradiction, we must negate our initial assumption: Jane =/= her brain.
I think substance dualism becomes clear now. If Jane isn't identical to her brain, or any part of it, then there isn't anything physical to which she is identical (if not her brain she wouldn't be identical to her arm, kidney, or that chair over there). But if she isn't identical to something physical, then she must be identical to something that is nonphysical. This is what I shall call the soul. QED.
greetings,
ReplyDeletehere's an objection:
from Jack's not knowing the image of the chapel what follows is the falsity of the initial assumption i.e., that he knows everything about her brain, not that there's a non-material substance (which is her) in which that image inheres. so a proof is still needed for this last claim.
Hi krimiyagard! I think this is question-begging. The point is that complete knowledge about the brain doesn't entail knowledge about what it is like for Mary to experience redness or the chapel. So we have good reason to think that complete knowledge of the brain is possible and yet utter ignorance with respect to the qualitative experiences of Jane.
Deletehi,
ReplyDeletewell, you'd be right if the materialist were arguing for materialism with that objection. but i don't think he is. he's simply pointing out that you're argument does not prove its conclusion. that is, given his materialism, all he's saying is that your argument does not tip the scales in favor of the conclusion that there's a non material substance rather than that the initial assumption is false. the materialist will cling to this possibility, for you haven't rule it out. he will argue:
if you have complete knowledge of the brain, you will know the image of the chapel
but you don't know the image
therefore, you don't have complete knowledge of the brain
so, it's just not possible for you to have complete knowledge of the brain and still not know the image. for, as far he's concerned, it would as if you had said 'assume you know everything about the brain' (i.e., Jack knows everything about Mary's brain) and 'assume that you don't know everything about the brain' (i.e., the image of the chapel).
given his materialism, all he's saying is that your argument does not tip the scales in favor of the conclusion that there's a non material substance rather than that the initial assumption is false.
ReplyDelete^ Yes, that is question-begging. Given his materialism, yes, my argument would be unsound. But his materialism is exactly what is in question.
"if you have complete knowledge of the brain, you will know the image of the chapel
but you don't know the image
therefore, you don't have complete knowledge of the brain"
^ I don't think so. Like I said they are defining physicalism so that it includes even the nonphysical at that point. I don't think qualia can be reduced so it would still be possible to know all of the *physical* facts and still not know all of the facts. Hence, the argument would still go through. Moreover, it is possible to have complete physical knowledge and still it would be impossible to know what it is like for Jane to have experienced redness. As I said before, Jane has privileged access to this information. No information about the brain isn't accessible only to her since it is an entirely physical system.
hmmm, i'm not sure. at the least, it seems you two are a standstill.
ReplyDeletethe materialist will ask: what is the proof that it is possible to know everything about her brain but not the image which she is expiriencing? the mere fact that you can imagine such a scenario? "well", he'll say, "i *can't* imagine it or i can imagine a scenario in which that isn't possible.
No, not the mere fact that I can imagine it. I gave an argument that it is impossible to know everything about the brain and for that fact to entail your knowing everything about Jane.
ReplyDeletewait, i'm unclear. the materialist wants to know your proof for this this premise: 'knowledge of everything about the brain does not entail knowledge of the image of the chapel that Mary is experiencing'.
ReplyDeleteKimiyagard, I'll just recommend a paper for you. See Nagel's 'What is it like to be a bat?' and 'Agains Materialism' in The Waning of Materialism. That might help clear things up.
ReplyDeletethanks. i've read that Nagel paper though. i'll try and look at the other one. these arguments from the expirience of qualia, although persuasive, are just not, i think convicing. i should note though that it seems to me your other argument from the content of the proposition 'philosophy is the highest good' is convicing. that's because that proposition is composed of universals, which cannot be material in any way. but i don't think that's the case with images (or other qualia).
ReplyDelete