An illusion of reality must have its categorical root in reality; which makes illusions of reality a direct function of reality. Which means that they are not in fact illusions at all, but merely reality. In other words, something which is an existential illusion is a contradiction, and cannot, by definition, exist. The lack of existence with respect to reality is what makes an illusion an illusion.
An illusion then, is purely an abstract concept. There is no such thing as an illusion qua illusion, because that’s a contradiction. We simply have reality, and functions of reality according to man’s ability to conceptualize it.
Further it means that there is no such thing as an illusion of consciousness, as the determinists like to describe human awareness of Self. For an illusory consciousness is merely a synonym for illusory reality: that is, you cannot know what is real (that is, what is True), because “you” qua “you”–as you understand you–is an illusion. So if reality cannot be an illusion because it must have its categorical root in actual reality, then consciousness cannot be an illusion for the same reason.
Besides, to claim that your consciousness is a direct effect of either an unconscious cause, like the laws of physics, or a conscious one, like God or some super-advanced alien race running a matrix-style computer program, makes the illusion of consciousness impossible because what is entirely an illusion cannot, again, by definition exist. You cannot have an illusion of a thing where the illusion is something distinct from that which is not an illusion because then that thing, being distinct–having “self”—is not an illusion, it is real. An illusion of consciousness which is utterly distinct from its “cause” is nothing less than real consciousness. And if it’s not distinct then it’s not real–it has no self–which means that it doesn’t exist; and thus “it” isn’t an illusion because “it” isn’t anything all.
So stop listening to people trying to convince you that you aren’t real, you have no real awareness, and that you cannot really know anything.