>It is probably just a difference in semantics but for me, it seems like consciousness is the only thing that is assuredly not an illusion.
It might be some bottomless, but it doesn’t look like an absolute impossibility. The classical "Brain in a vat" thought experiment gives a good insight of nothing theoretically prevent what we assume for assuredly "real" might be a virtual scenario.
Or taking an other metaphor, maybe we are like cinema screens and the film of our life is all pure illusion, while the most classical interpretation would suppose that the screen itself undoubtedly "exists" – the screen being the analogous to the current conscious attention in the metaphor. But nothing prevent to wonder that the whole cinema is some kind of hologram in solid light, so while the screen does "exist", it’s nonetheless itself an illusion.
It might be some bottomless, but it doesn’t look like an absolute impossibility. The classical "Brain in a vat" thought experiment gives a good insight of nothing theoretically prevent what we assume for assuredly "real" might be a virtual scenario.
Or taking an other metaphor, maybe we are like cinema screens and the film of our life is all pure illusion, while the most classical interpretation would suppose that the screen itself undoubtedly "exists" – the screen being the analogous to the current conscious attention in the metaphor. But nothing prevent to wonder that the whole cinema is some kind of hologram in solid light, so while the screen does "exist", it’s nonetheless itself an illusion.
[1] https://en.wikipedia.org/wiki/Brain_in_a_vat