my aim in this paper is to raise and discuss some philosophical questions about virtual reality (vr). the most fundamental problem concerns the ontological nature of vr: is it real or fictional? is vr comparable to illusions, hallucinations, dreams, or worlds of fiction? are traditional philosophical categories at all sufficient to give us understanding of the phenomenon of vr? in approaching these questions, i shall employ possible world semantics and logical theories of perception and imagination as my philosophical tools. my main conclusion is that vr is comparable to a 3-d picture which can be seen from the inside.