Material world essentially implies that the world exists independent of the mind. Physical world exists owing to its perception by the mind or rather a mind ("the mind" might contribute to the problem of sollipsism) or even if no mortal mind is perceiving the world, God perpetually perceives it so the physical world exists. It cannot be similar to Plato's theory of forms, for Plato's ideas bend towards rationalist realm. And Plato maintains that the forms are innate, and help move from universal to particulars. While Berkeley is fundamentally an empiricist.

Permanence is explained by the Berkeley through the notion of god (eternal mind) i.e things in the outside world exist permanently (i.e in present, past and future) even when I or another individual (finite mind) is not perceiving the thing because it is always being perceived by the eternal mind i.e god.

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