Reality is the totality of existence or what all existing entities have in common. It is often contrasted with appearance, opposing what is with what seems to be, although the accuracy and fundamentality of this contrast are disputed. Various criteria for distinguishing real from unreal entities have been proposed, including causal powers, mind-independence, and being non-illusory. The concept of reality overlaps with notions such as being, existence, world, actuality, and truth.