I would like to first explain my understanding of "to exist is to be perceived".
How do you know something exists? Therefore, some philosophers say, if you do not experience or rationally realize the existence of a thing, how do you know that a thing exists? So when you know that something exists, you must first have empirical and rational experience. It is from this perspective that Berkeley said: Existence is to be perceived. He believes that it is impossible for you to know whether something exists or not without being perceived, and even your mind will not think about that thing at all. So I want to change Berkeley's words to this: A person knows the existence of a thing because he perceives it first.
All kinds of materialists are certainly the most critical of it. Materialism believes that existence is independent of human knowledge, perception, and consciousness. This is of course correct. A thing either exists or does not exist. Whether a person perceives it or not, the existence or absence of that thing is objectively unchanged.
The views of materialism and empiricism on existence are not completely contradictory. Because materialists emphasize that the existence of a thing does not depend on human will, while empiricists emphasize that people must first perceive a thing before they know it exists. One starts from the existence of things itself, and the other starts from people’s feelings.