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> the knowledge of redness purportedly does not deductively follow from the knowledge of any amount of physical facts. Which is just a bare assertion, not an a
by pdonis 4y ago
> the knowledge of redness purportedly does not deductively follow from the knowledge of any amount of physical facts.
Which is just a bare assertion, not an argument. Nothing in the premises of Jackson's thought experiment entails this or requires it. To a physicalist, knowledge of redness is knowledge of a physical fact, so this statement is simply false.
> surgery is the same type of invalid move
If you're hung up on the word "surgery", then eliminate it: it's just as possible that Mary could simply imagine, based on her complete knowledge of all physical facts, what it would be like for her to see red, without having to do any surgery at all. You might say this is implausible, but so is the premise that Mary has complete knowledge of all physical facts. But that's the premise of the thought experiment.
> Under dualism
Jackson's thought experiment does not prove that dualism must be true. Nor can you assume that dualism is true as a premise, since that is just a circular argument. A physicalist, like me, simply does not think dualism is true, and it is no argument against that to show what would be the case if dualism were true. You need to argue, from premises that don't already contain dualism, that dualism must be true. Jackson didn't do that. Nor do any of the other arguments described in the article, including the Knowledge Argument.
- naasking 4y agoYou're not telling me anything I don't already know about physicalism or Mary's room. What's in dispute here is whether any physical action is a legitimate answer to the Knowledge Argument, so I'm going to ignore the rest and focus on this disagreement: "Imagining" is not the same as surgery. Do you agree or disagree that Mary constructing a red LED to experience redness is not a legitimate response to the Knowledge Argument?
- pdonis 4y ago> Do you agree or disagree that Mary constructing a red LED to experience redness is not a legitimate response to the Knowledge Argument? It depends on what you think the Knowledge Argument is supposed to prove. If you think the Knowledge Argument is supposed to prove that physicalism is false, then I disagree. To refute physicalism, it is pointless to say that some physical processes are not "knowledge". Even if the physicalist agrees, that in no way refutes physicalism. The physicalist simply says that the processes that Mary induces in her brain by constructing a red LED (or doing surgery on her optic nerve, or just imagining what seeing red would be like), even if they are not "knowledge", are still physical processes, and that those physical processes are Mary's experience of seeing red. Nothing in the Knowledge Argument refutes that. If you think the Knowledge Argument is supposed to prove that there are physical things that aren't "knowledge" (whether or not there are also non physical things is then a separate question), then I neither agree nor disagree as a matter of physics, since what we use the word "knowledge" to refer to is a matter of definitions of words, not physics. I have no problem with accepting your definition of the word "knowledge" for purposes of this discussion. I just don't think accepting that definition says anything about whether or not physicalism is true.
- naasking 4y ago> The physicalist simply says that the processes that Mary induces in her brain by constructing a red LED (or doing surgery on her optic nerve, or just imagining what seeing red would be like), even if they are not "knowledge", are still physical processes This isn't relevant. Nobody is really disputing that physical processes cause qualia. You don't see the redness of an apple until the apple actually enters your visual field. Cause=physical event, result=qualia. Even dualists agree with this. Therefore the Knowledge Argument is not about whether any physical process is causally linked to qualia, it's specifically about whether qualia can be deduced only from factual knowledge, because under physicalism, all facts are physical facts. If physicalism is true, then all facts are third-party objective physical facts. Therefore quale are physical facts. If given an understanding of all physical facts, then Mary should be able to deduce her quale. If she cannot deduce her quale (or it seems very implausible), then either some mistake has been made or physicalism is false. Where is the mistake? You cannot answer this question by saying her knowledge gives her the ability to trigger the usual physical process to cause qualia, because the question is about the deduction. The only outcomes of this thought experiment are one of: 1. denying that physicalism is true, or 2. denying that quale are facts, 3. accepting that Mary would be able to deduce her quale, 4. concluding that the thought experiment contains some inherent contradiction.
- dragonwriter 4y agoIf Mary had (and had the capacity to conpletely analyze) all data on all physical processes in the universe, she could deduce her, and all other, qualia.