Do you exist if I do not believe you exist-is the question. Of course one is not sure.An objective reality cannot exist without somebody perceiving it.If you believe it still exists independent of your perception,you may do so but that is only a belief and hence is subjective. It is therefore safe to presume that nothing exists without our perceiving that it exists. The question that arises is whether a reality has necessarily to exist if we believe it exists.By way of example ,I believe ghosts and gnomes exist and does that mean they exist as an objective reality ? No.Additional conditions apply .Verifiability of the evidence suggesting their existence should possibly be one of the conditions. Of course one would ask what we mean by verifiability.Suppose there is a mountain near the horizon and everybody's perception and everything else points to the possibility of its existing. Which means the sensory impressions of all the people with respect to the object tally in all respects. We may therefore conclude the mountain exists. The unanswered question is whether several assessments tallying with one other and based upon "physical verifiability" make the mountain an objective reality . Since we cannot separate our consciousness from what we perceive outside of ourselves the only way of verifying the existence of the objective reality is to cease to be the experiencer and become a part of the experienced. This is what the Hindus call brahma gyan(knowledge of Brahma)