Adding to your post, let's consider an example, i.e., "redness" as it is commonly understood. Dualists will relegate "redness" to an experience because, to them, matter is devoid of things like "redness" by virtue of the dualist's presupposed concept of matter. The dualist still have to deal with a number of problems stemming from his position, e.g., the interaction problem, but he can at least ostensibly locate "redness" in reality, viz., the Cartesian mind. Even if it is an illusion, it exists as an illusion in the mind. Materialists, who typically dispense with the Cartesian immaterial mind but stick with a broadly Cartesian concept of matter, either live in the vain hope that they can eventually locate "redness" somewhere in matter, or come to the absurd eliminativist conclusion that "redness" simply doesn't exist or that it is an illusion. Of course, if it is an illusion, then it still exists as an illusion, hence the incoherence of eliminativist materialism. Aristotelianism accepts a richer view of matter in which "redness" does exist, so there is no need to posit this bizarre and unbridgeable division between physical things and immaterial mental qualium.

"Selves" and zombies also crop up in these conversations, but they are neither here nor there. We're talking about the existence of things like "redness". Talk of "selves" is no doubt related to the Cartesian identification of mind and self, but something that is entirely irrelevant to the question at hand.

> Materialists, who typically dispense with the Cartesian immaterial mind but stick with a broadly Cartesian concept of matter, either live in the vain hope that they can eventually locate "redness" somewhere in matter, or come to the absurd eliminativist conclusion that "redness" simply doesn't exist or that it is an illusion.

Funny how you keep calling materialism "absurd" and "incoherent", yet provide no coherent argument of your own to support this position. If anyone unfamiliar with this subject is reading this thread, rest assured that the anti-materialist sentiments espoused here are a minority view. A recent survey of academic philosophers found that the majority support a materialist philosophy of mind, so frankly, these charges of incoherency and absurdity don't pass a lay person's basic sniff test.

As for the existence of "redness" specifically, I can easily point out how the various thought experiments that allegedly support the existence of redness are fallacious. So instead of making further bold claims, would you care to present such an argument for scrutiny?

> Of course, if it is an illusion, then it still exists as an illusion, hence the incoherence of eliminativist materialism.

A car is also an illusion under materialism. But clearly I drove something to work this morning. So does this apparent incongruity entail some incoherency in materialism? Or is the problem really that you're attacking a straw man?

> But can it? To say something is an illusion is to say that is really an experience of something else.

Your definition for "illusion" begs the question by simply assuming a subject is needed, ie. an "I" must experience an illusion. Rather, an illusion is simply describing the relation between perception and truth. If a perception, taken at face value, entails a false conclusion, then it's an illusion.

Even the basic dictionary definitions of illusion make no reference to a subject. They're all of the form of "a false idea or belief", or "a deceptive appearance or impression". Beliefs and appearances are attributes we can ascribe to mechanistic systems too, like computers, which can have sensors plugged into Bayesian inference engines that can infer false "beliefs".

So requiring a subject is a property that you have imposed on the meaning of illusion, it's not intrinsic to it.

I made no reference to a subject either. For "my" experiences to be not really "anybody's" experiences is a somewhat separate problem. As is a belief that I don't really have any beliefs, and so on. Any attempt to eliminate qualia or self or intentionality, etc. as being fundamental realities runs into the problem that all these things are more fundamental to my understanding than any proposed alternative.

Your definition of illusion still begs the question, either by assuming a subject or assuming a reduction to further experience is needed. Like I said, illusion only requires that perception differ from truth.

> Any attempt to eliminate qualia or self or intentionality, etc. as being fundamental realities runs into the problem that all these things are more fundamental to my understanding than any proposed alternative.

1. Perception is fundamental to understanding. Whether experience is fundamental is very questionable.

2. Being fundamental doesn't entail something is irreducible. Being in a car is fundamental to driving on a road, that doesn't entail cars are irreducible.