n. the philosophical position that denies the independent existence of matter as a substance in which qualities (see primary quality; secondary quality) might inhere. Sensible objects are held to exist as the sum of the qualities they produce in the perceiving mind, with no material substratum. The best known philosophy of this kind is that of George Berkeley. It is difficult to distinguish such a position from idealism, which holds that mind is essential to all reality and that things and qualities exist only as perceived. Compare materialism.