Esse Est Percipi Well, if we put aside Berkeley's context - which I frankly have to re-read - and simply take the phrase as is stated, it's a problem.
To be a human being entails having perception. If you do not have perception - say are in a comma, you can't well categorize or think of anything.
On the other hand, obviously others things "are", irrespective of us in some manner, rocks, water, etc. So far as we know, they don't have perception but exist. We happen to give them the characteristics (automatically, not a choice) of "hardness", "wetness", etc.
But having a perception does not entail that one is being perceived. The best one can do is assume another person perceives you - or another animal. But we can't go beyond this assumption to proof.