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by canjobear 650 days ago
The nonphysicality of consciousness isn't taken as axiomatic, there are arguments for it. Consider the argument from knowledge, summarized in TFA:

> A related argument known as the “knowledge argument” was famously put forward by Frank Jackson. Imagine Mary, a scientist of the future who, for whatever reason, has spent her entire life in a black and white room, never having experiences of colors. She has, nevertheless, through her studies come to learn all the physical facts there are to know about the physics and physiology of color perception. For example, she knows down to the last detail what is going on in the surface of a red apple, and in the eyes and nervous system, when someone sees the apple. Suppose she leaves the room and finally comes to learn for herself what it is like to see red. In other words, she comes for the first time to have the qualia associated with the conscious experience of seeing a red apple. Surely she has learned something new. But since, by hypothesis, she already knew all the physical facts there were to know about the situation, her new knowledge of the qualia in question must be knowledge of something over and above the physical facts.

In the thought experiment, when Mary sees red for the first time, it seems that she gains new knowledge that she did not have before even though she knew everything there is to know about the properties of matter involved. You have to either accept that she learned something nonphysical, or deny that she learned anything. The version of this that I learned first was "what is it like to be a bat?" https://en.wikipedia.org/wiki/What_Is_It_Like_to_Be_a_Bat%3F

Another one that I can recall offhand, from Descartes: Physical things have extension in space. One way to test whether something has extension in space is whether you can cut it in half. But your consciousness can't be cut in half, you can't even conceive of what this would mean. So it's not physical.

Make of the arguments what you may. I wrote term papers against both of the above in undergrad. But it's definitely something people have thought carefully about, not just an ideological assertion that consciousness Must Be Different.

2 comments

> In the thought experiment, when Mary sees red for the first time, it seems that she gains new knowledge that she did not have before even though she knew everything there is to know about the properties of matter involved. You have to either accept that she learned something nonphysical, or deny that she learned anything.

No, you don't. You just have to accept that the facts about physical phenomenon that can be learned through language are different than the physical experience of physical phenomena themselves, and that learning the latter is distinct from learning the former. The latter, however, is obviously physical.

And, even if it wasn't wrong in that way, that would be an argument for the nonphysicality of some subset of the subjects of knowledge, not an argument for the nonphysicality of consciousness.

> the facts about physical phenomenon that can be learned through language are different than the physical experience of physical phenomena themselves

Whether she learned through language is irrelevant. Before seeing red, she might have learned about it by consulting extensive charts of the brain, or (black-and-white) videos of timecourses of brain activation. Maybe she even got to run computer simulations of her own brain response.

By construction Mary already knew everything physical about the color red, so the new knowledge she gained through consciously experiencing it is not knowledge about anything physical.

Indeed, I think the parent comment presents a false dichotomy fallacy. Thanks for catching it
The hypothetical scenario of knowing all of the physical facts about what it is like to see the color red does not seem particularly possible to me even without the constraint that it happen without having seen colors before. Since we are assuming that Mary understands the color red to a dramatically deeper degree than any human actually has, I don’t see how you can conclusively state that her reaction to finally seeing it would be something other than “yep that’s exactly what I expected”, with the only new information gained being that her knowledge actually does correspond to reality (or at least to her perception of such).