I'm actually writing a paper on this for my first philosophy course. One excerpt is:

we ought to say any given X is a Y if X displays every possible observable property of a Y. If X were not actually a Y but satisfied the previous statement then we ought to say that X is still an instance of Y ... When I say my father is a human I am presupposing a multitude of properties that my father has. Similarly we only know an object is a tree if it has leaves, a trunk, roots, and any other general property we might assign to a tree. In this way the word Tree is an abstract data type (T), or a class of objects with certain behaviors. Any possible object x which satisfies T is an element of T. So a duck is a duck because it acts and looks like a duck, not because of the actuality of the situation.

I continue along these lines, and it does not seem to relate to the problem of reality until we consider the universe as an object. There exist certain mechanisms we use to acquire knowledge about the world, these mechanism presuppose something about reality (A) and make some conclusion B. So these mechanisms have types. Science is an example on this "epistemic function" which assumes properties of the universe U and concludes something else K (S:U →K). We have reason to believe that the universe we perceive satisfies this function S.

If tomorrow it was discovered that our universe was a simulation in a computer then would this simulation still satisfy every property denoted by U? I think it would, and as S would still be satisfied.

So if reality was an illusion it would have no effect on our epistemic ability of perception of knowledge and therefore wouldn't matter.

I can't say that reality isn't illusionary, but I believe I can say that the statement "reality is illusionary" is meaningless because it doesn't matter.