@JohnSmithb9be well I've always found the view odd and nonsensical. Consciousness to me seems self evident, manifest, irreducible. This subjective space we experience is the most fundamental, the most obvious, and the most indubitable reality. It's the only thing that can be confirmed, really (in addition perhaps to mathematical tautology).
So for me consciousness, whatever its nature and connection (or lack thereof) to something external and/or material, cannot possibly be an illusion. Experience simply is, or is not.
But it's a view I've heard expressed, particularly among some of the younger East Asian thinkers I encountered in my travels. Perhaps something about our advances in digital, neuroscience, quantum physics, causality . . . . perhaps something about our advances in these fields leads to some sort of hyperskepticism or absolute deconstructionism that inclines us towards suspicion (or perhaps simply towards certain language games) that lead to these sorts of claims.
I'm not sure if that addressed your question at all though. If you're referring to solipsism, the doubt that OTHER people are conscious, that's an entirely different matter.
One of the most fascinating things to me is considering other sorts of consciousness such as appear in sci-fi or whatever. Digital consciousness, hive minds, fungal consciousness . . . . what IS consciousness, really? Something to do with information and information patterns evolving, changing yet maintaining shape, interfacing with energy in some way, passing on information in evolving form . . . . idk.
Whatever the case, what's going on in my own head can't be an illusion.
@JesseTate I have some counterarguments, if you want them:
While you & i feel convinced that we mentally exist, note that this is not strong evidence. Almost all humans that do NOT exist (such as fictional & imaginary humans) feel exactly the same way.
I do agree that it seems extremely likely that Something is Happening in Reality in General. Ie, it seems dubious that there is no reality. But even this assumption does not prove the special status of human minds. For example, 100% of our universe might be nonspecial, yet 1 special, well-informed mind outside of our universe may be contemplating it in detail, examining your mind & thoughts during your introspection. Or in other words, we might be a fictional universe, being read about by a 'conscious' reader who has access to our thoughts.
Personally i believe humans are real (for all our intents & purposes) & important, but that 'consciousness' & qualia are imaginary.