"Entailments of perception" is too broad and so doesn't pick out the right target here. My immediate perception entails that there is a red cup a short distance

"Entailments of perception" is too broad and so doesn't pick out the right target here. My immediate perception entails that there is a red cup a short distance in front of me. Entailments about the outside world can certainly be false (e.g. that red is a property of the cup that lives in the outside world). But what does the perception of a red cup entail about my inner state? Nothing that I can tell, except that I am having a perception of a specific kind. What does it mean to say that my perception of a specific kind is an illusion? It's hard to say. The perception gives me certain powers of discrimination that entail the necessary veracity of those aspects of the perception (i.e. I can tell red from blue, red from pain, red from pitch, etc). Are there aspects of perception that don't play a role in any kind of discrimination? Not that I can tell. And so perceptions themselves just don't seem like the kinds of things that can be properly called illusions.