Whenever, I hear someone like, say, Daniel Denett say conscious is an "illusion", I'm always left pretty stumped. Firstly, both the terms "consciousness" and "illusion" are generally left undefined, although this is more apparent with the term "illusion". With this, I have to use the default definitions of these terms, "consciousness" being a somewhat self-explanatory "state of conscious awareness", and "illusion" being "a delusion of some sort". This is really where the main problem arises for me. How can one claim that consciousness is an illusion when the concept of "illusion" requires a subject to be deluded, which the original claim actively denies the existence of? Granted, this subject doesn't have to be an "I", but the denial of any decieved subject at all seems to negate the argument itself.
The other problem I have with the claim is that it seems to contradict the fairly self evident claim that, as Nietzsche put it, "It thinks, therefore it is".
Is the claim really as nonsensical as it seems, or am I missing something big? Perhaps the definition of a term or multiple terms?