1.) For Berkeley, a being that exists by itself would have to be a self-perceiver, since what doesn’t perceive itself requires another as a condition of its existence.
2.) The non perceptive thus cannot be self-existent. This includes the inanimate, but also includes mere animal life since sense organs do not perceive themselves. The eye can see pictures or reflections of an eye but neither of these are animate organs (neither can go blind, for example).
3.) To exist by oneself first becomes possible for intelligence and is impossible outside of it. Some self-perceivers clearly begin to exist, but this “beginning” applies to them so far as they have been concretized in animal, organic existence, which we know from (2) need not characterize every dimension of a self-perceiver.