ABSTRACT
George Berkeley’s idealism, which he called immaterialism, has two fundamental theses, which we can call the ontological and the metaphysical. His most original and challenging argument is his denial that there is any substantive difference between primary qualities such as shape, size and motion, and secondary qualities such as colour, taste and texture. Berkeley’s thought is that what is immediately perceived can always be experienced in a single perception, that our perceiving it now does not depend upon our perceiving anything else, either now or at some other time. His examples, such as our immediately perceiving a painting or words in a book but not what the painting is of or the words describe, tend to emphasize that what is immediately perceived is present. But it is important to see it is not just being present but being wholly present that matters for immediate perception.
