BERKELEY. 217 none, for the combination of opposite elements in one idea would be a contradiction in terms. Motion in general, neither swift nor slow, extension in general, at once great and small, abstract matter without sensuous determinations — t^iese can neither exist nor be perceived. The "materialistic" hypothesis — so Berkeley terms the assumption that a material world exists apart from perceiving mind, and independently of being perceived — is, first, unnec- essary, for the facts which it is to explain can be explained as well, or even better, without it ; and, second, false, since it is a contradiction to suppose that an object can exist unper- ceived, and that a sensation or idea is the copy of anything itself not a sensation or idea. Ideas are the only objects of the understanding. Sensible qualities (white, sweet) are subjective states of the soul ; sense objects (sugar), sensation- complexes. If sensations need a substantial support, this is the soul which perceives them, not an external thing which can neither perceive nor be perceived. Single ideas, and those combined into objects, can exist nowhere else than in the mind; the being of sense objects consists in their being perceived {esse est pcrcipi). I see light and feel heat, and combine these sensations of sight and touch into the sub- stance fire, because I know from experience that they con- stantly accompany and suggest each other.* The assump- tion of an "object" apart from the idea is as useless as its existence would be. Why should God create a world of real things without the mind, when these can neither enter into the mind, nor (because unperceived) be copied by its ideas, nor (because they themselves lack perception and power) produce ideas in it? Ideas signify nothing but them- selves, i. e., affections of the subject. The further question arises. What is the origin of ideas? Men have been led into this erroneous belief in the reality of the material world by the fact that certain ideas are not subject to our will, while others are. Sensations are distin-
- The fire that I see is not the cause of the pain which I experience in
approaching it, but the visual image of the flame is only a sign which warns me tiot to go too near. If I look through a microscope I see a different object from the one perceived with the naked eye. Two persons never see the same object, they merely have like sensations.
