What grounds are there for excluding "how the knowing subject that is an emergent property of the matter of the brain experiences colour" from "all knowledge about colour"?
fenomas correctly points out the argument is begging the question based on the I've raised here, but the argument is even more deeply flawed than that because it assumes that "knowledge" is a thing rather than an activity of a knowing subject.
If you take the epistemology of a knowing subject seriously then knowing is an activity of the subject, with the ontology of an action rather than a thing. Activities are not conserved in the way things are. It is easy to slip past what "know everything there is to know" means when we assume (incorrectly) that knowledge is thing-like: we can image books full of sentences that exhaustively list laws and properties. One might say that if Mary knows Maxwell's equations and a long list of information about matter she might "know everything", but considered as an action, to "know everything" means "to be able to have any thought that anyone might be able to have about the thing", or something similar.
From this, we can immediately draw an important inference: Mary is not a human being, so this is not an argument about human beings. Not even in the wildest philosopher's imagination could any human being be able to have every thought about light that could be had. There are no-doubt "single thoughts" of such enormous length and complexity that they could not be fit into a human lifetime. And because the actions of the mind are serial (mostly) rather than parallel, the absurdity of the proposition that we can "know everything there is to know" is revealed. Human life is simply too finite for it.
Any expert will attest to this: no matter how much we learn, with ongoing experience there is always more.
So like all imaginary arguments, the primary purpose of this one is to mislead us about the subject. It isn't about human beings or human knowledge. It is about some other kind of being, unrelated to humanity. Which I guess might be interesting if you're in to that kind of thing, but personally I'd rather spend my time focused on the world that exists, not the world of some philosopher's imagination.
If the argument were honestly stated it becomes a tautology:
"Imagine a knowing subject that is capable of thinking every thought about a given subject, which necessarily includes all the thoughts a knowing subject might have when it physically interacts with the material reality the subject describes (otherwise it wouldn't be able to think every thought about the subject). Is such a knowing subject capable of knowing the thoughts a knowing subject might have when it physically interacts with the material reality the subject describes?"
fenomas correctly points out the argument is begging the question based on the I've raised here, but the argument is even more deeply flawed than that because it assumes that "knowledge" is a thing rather than an activity of a knowing subject.
If you take the epistemology of a knowing subject seriously then knowing is an activity of the subject, with the ontology of an action rather than a thing. Activities are not conserved in the way things are. It is easy to slip past what "know everything there is to know" means when we assume (incorrectly) that knowledge is thing-like: we can image books full of sentences that exhaustively list laws and properties. One might say that if Mary knows Maxwell's equations and a long list of information about matter she might "know everything", but considered as an action, to "know everything" means "to be able to have any thought that anyone might be able to have about the thing", or something similar.
From this, we can immediately draw an important inference: Mary is not a human being, so this is not an argument about human beings. Not even in the wildest philosopher's imagination could any human being be able to have every thought about light that could be had. There are no-doubt "single thoughts" of such enormous length and complexity that they could not be fit into a human lifetime. And because the actions of the mind are serial (mostly) rather than parallel, the absurdity of the proposition that we can "know everything there is to know" is revealed. Human life is simply too finite for it.
Any expert will attest to this: no matter how much we learn, with ongoing experience there is always more.
So like all imaginary arguments, the primary purpose of this one is to mislead us about the subject. It isn't about human beings or human knowledge. It is about some other kind of being, unrelated to humanity. Which I guess might be interesting if you're in to that kind of thing, but personally I'd rather spend my time focused on the world that exists, not the world of some philosopher's imagination.
If the argument were honestly stated it becomes a tautology:
"Imagine a knowing subject that is capable of thinking every thought about a given subject, which necessarily includes all the thoughts a knowing subject might have when it physically interacts with the material reality the subject describes (otherwise it wouldn't be able to think every thought about the subject). Is such a knowing subject capable of knowing the thoughts a knowing subject might have when it physically interacts with the material reality the subject describes?"