Berkeley denies that we have ideas of pure extension or motion, because, although we do actually deal with these and find them intelligible, we can never obtain a state of mind in which they appear as the content. He applies this psychological test because of his adherence to the general empirical postulate that knowledge is limited to the individual content of its own individual states. "It is a universally received maxim," he says, "that everything which exists is particular." Now the truth of mathematical reckoning is not particular, but is valid wherever the conditions to which it refers are fulfilled. Mathematical reckoning, if it is to be particular, must be regarded as a particular act or state of some thinker. Its truth must then be construed as relative to the interests of the thinker, as a symbolism which has an instrumental rather than a purely cognitive value. This conclusion cannot be disputed short of a radical stand against the general epistemological principle to which Berkeley is so far true, the principle that the reality which is known in any state of thinking or perceiving is the state itself.
The Transition to Spiritualism.
§ [132]. This concludes the purely phenomenalistic strain of Berkeley's thought. He has taken the immediate apprehension of sensible objects in a state of mind centring about the pleasure and pain of an individual, to be the norm of knowledge. He has further maintained that knowledge cannot escape the particularity of its own states. The result is that the universe is composed of private perceptions and ideas. Strictly on the basis of what has preceded, Hylas is justified in regarding this conclusion as no less sceptical than that to which his own position had been reduced; for while he had been compelled to admit that the real is unknowable, Philonous has apparently defined the knowable as relative to the individual. But the supplementary metaphysics which had hitherto been kept in the background is now revealed. It is maintained that though perceptions know no external world, they do nevertheless reveal a spiritual substance of which they are the states. Although it has hitherto been argued that the esse of things is in their percipi, this is now replaced by the more fundamental principle that the esse of things is in their percipere or velle. The real world consists not in perceptions, but in perceivers.
Further Attempts to Maintain Phenomenalism.
§ [133]. Now it is at once evident that the epistemological theory which has been Berkeley's dialectical weapon in the foregoing argument is no longer available. And those who have cared more for this theory than for metaphysical speculation have attempted to stop at this point, and so to construe phenomenalism as to make it self-sufficient on its own grounds. Such attempts are so instructive as to make it worth our while to review them before proceeding with the development of the spiritualistic motive in subjectivism.
The world is to be regarded as made up of sense-perceptions, ideas, or phenomena. What is to be accepted as the fundamental category which gives to all of these terms their subjectivistic significance? So far there seems to be nothing in view save the principle of relativity. The type to which these were reduced was that of the peculiar or unsharable experience best represented by an individual's pleasure and pain. But relativity will not work as a general principle of being. It consigns the individual to his private mind, and cannot provide for the validity of knowledge enough even to maintain itself. Some other course, then, must be followed. Perception may be given a psycho-physical definition, which employs physical terms as fundamental;[282:12] but this flagrantly contradicts the phenomenalistic first principle. Or, reality may be regarded as so stamped with its marks as to insure the proprietorship of thought. But this definition of certain objective entities of mind, of beings attributed to intelligence because of their intrinsic intelligibility, is inconsistent with empiricism, if indeed it does not lead eventually to a realism of the Platonic type.[283:13] Finally, and most commonly, the terms of phenomenalism have been retained after their original meaning has been suffered to lapse. The "impressions" of Hume, e. g., are the remnant of the Berkeleyan world with the spirit stricken out. There is no longer any point in calling them impressions, for they now mean only elements or qualities. As a consequence this outgrowth of the Berkeleyanism epistemology is at present merging into a realistic philosophy of experience.[283:14] Any one, then, of these three may be the last state of one who undertakes to remain exclusively faithful to the phenomenalistic aspect of Berkeleyanism, embodied in the principle esse est percipi.
Berkeley's Spiritualism. Immediate Knowledge of the Perceiver.
§ [134]. Let us now follow the fortunes of the other phase of subjectivism—that which develops the conception of the perceiver rather than the perceived. When Berkeley holds that
"all the choir of heaven and furniture of the Earth, in a word, all those bodies which compose the mighty frame of the world, have not any subsistence without a Mind,"