[cchooper]

You're both (a little) wrong! :)

You can't call something an illusion just because its true nature is misunderstood. An illusion is something that looks deceptively like something else. A hologram of a table is an illusion, but just misunderstanding the nature of a table (e.g. misunderstanding the fundamental particles from which it's constructed) does not make it an illusion.

Saying that time is an illusion is like saying that we appear to be living in a universe with time, but actually we don't. We are in fact experiencing something that looks like time, but isn't really time.

But obviously we do live in a universe with time, and the fact that time may turn out to be something strange or unexpected does not make it an illusion. It just means we misunderstood its true nature.

[TrevorJ]

I believe they are saying time is a concept that is useful for explaining certain local experiences, but under certain more global circumstances, the defining characteristics of the concept of time could potentially change, causing us to need a new concept to describe it.