Reality is the sum or aggregate of all that is real or existent within the universe, as opposed to that which is only imaginary, nonexistent or nonactual. The term is also used to refer to the ontological status of things, indicating their existence. In physical terms, reality is the totality of a system, known and unknown.

In Western philosophy, metaphysics has become the study of the fundamental nature of all reality — what is it, why is it, and how are we can understand it. Some treat metaphysics as the study of “higher” reality or the “invisible” nature behind everything, but instead, it's the study of all of reality, visible and invisible.

Reality is mental, consisting of conscious moments, either individual events, in our own minds, or in some universal mind. Today that position is represented by philosopher David Chalmers, under the label of “panpsychism” (that is, “universal mind”).

Reality is everything in your brain. It is a hard concept to grasp, but consider this; there are no actual colours or sounds or smells outside. So what is outside? Well, colour consists of electromagnetic waves, and the colour we see depends on the length of these waves. Sound is compressed airwaves and smell is pungent air molecules.