Originally Posted by Ejayrazz

It depends what you mean by exist. This is a loaded word. It is the root of the word existential and matters that are existential usually deal with subjective individual perception. Ontologically, we have reality, epistemically we have knowledge, and existentially we have meaning. These three are not necessarily always the same. In reality it is hard to say if the friend is still there, because the only way we seem to declare something as real, is if we have optic/sensual evidence (which in this case we don't - no camera, etc). Epistemically, we know that just because the person is out of sight they will be able to return into sight. This we learn at an early age. As babies we believe something is gone when it is out of sight, but experience tells us otherwise. Then of course we have the existential part. Do you believe your friend is still there? This can go both ways. For instance, your friend leaves the room and somehow dies. You may still believe your friend exists (life after death, or maybe deny yourself that he did die). Just some thoughts... To answer your big question: Do we exist? I would have to say it is a matter of belief. Many believe we are simply an aggregate of materials, whereas others attribute an immortal soul to our being or even say we are an agglomerate of living materials that join in one symbiotic whole at the atomic level. I like to join hands with Berkley who said "to be is to believe"