Leibniz, the first of German philosophers, although an enemy of Locke's sensualism and of his slackness in logic, was even more explicit in assigning a mental seat to all sensible objects. The soul, he said, had no windows and, he might have added, no doors; no light could come to it from without; and it could not exert any transitive force or make any difference beyond its own insulated chamber. It was a camera obscura, with a universe painted on its impenetrable walls. The changes which went on in it were like those in a dream, due to the charge of pent-up energies and fecundities within it; for the Creator had wound it up at the creation like a clock, destined to go for ever, striking infinite hours, with ever richer chimes.

Here, in miniature, with a clearness and beauty never afterwards equalled, we have the nature and movement of the transcendental self set forth before us: a closed circle of experience, admitting of no relations with anything beyond, but infinite in its own potential developments, and guided by an inner force, according to an innate unconscious plan. All duties, all principles of interpretation, all data, all visioned objects, operated within this single life, diversifying its field of view, and testifying to its secret endowment.

Nevertheless, the later idealists, ungrateful to Locke for their first principle, were ungrateful also to Leibniz for their ultimate conception, anticipated by him in all its completeness. There were reasons, of course, for this ingratitude. Leibniz, like the transcendentalists, had supposed that the objects of sense, as experience reveals them, were begotten out of the latent nature of the soul; but he had also conceived that there were many souls, as many as atoms in the physical world, and that the images arising in each were signs of the presence and actual condition of its companions. Thus perception, while yielding directly only an idea, as in a dream, was indirectly symbolic of an outer reality, like a dream significant and capable of interpretation. And being an undaunted rationalist, Leibniz assumed that the sooth-sayer capable of reading this dream was reason, and that whatever reason conceived to be right and necessary actually must be true in the great outer world.

It was at this point that Kant deviated into his radical subjectification of knowledge. His mind had been more open than that of Leibniz to the influences of English psychology, it had stewed longer in its own juice, and he could not help asking how, if the senses could reveal only ideas of sense, reason was ever able to reveal anything but ideas of reason. Those inferences about the vast world outside, which Leibniz had allowed his spirits to make in their solitary confinement, were reduced by the more scrupulous Kant to scribblings upon their prison walls. These scribblings he officially termed the ideas of pure—that is, of unsupported—reason; but in his private capacity he gently continued to agree with Leibniz and to believe them true.

There was no anomaly, according to Kant, in this situation. An idea might by chance be the image of a reality, but we could never know that it was. For the proof would have to be supplied by a further idea, and would terminate in that. The hypothesis and the corroboration would alike be mental, since experience was of ideas and could envisage nothing but the vicissitudes of the mind.

If you had asked Leibniz what determined the order in which perceptions came into any mind, he would doubtless have answered that the Creator did so, or (translating that symbol into its analytic equivalent in his system) that what did so was the innate destiny or predisposition of that mind to develop in harmony with the best possible universe. Here is a very remarkable unconscious principle of evolution seated in the spirit and presiding over all its experience. This is precisely what is meant by a transcendental principle.

This principle, unconscious as it is, sometimes betrays its mighty workings to consciousness. Besides the incidental multitude of ideas which it breeds, it makes itself felt in subterranean strains and rumblings, in the sense of movement and of longing. This darker but deeper manifestation of the transcendental clock-work Leibniz called appetition, and under the name of Will it has played a great part in later German systems. To call it Will is, of course, to speak improperly and mythologically, for actual willing requires an idea of what is willed. When we say a man doesn't know what he wants, we mean that he can will nothing, for lack of a clear idea of his interests and situation, although he doubtless wants or lacks many specific things, the absence of which is rendering him unhappy and restless. These instinctive appetitions for objects of which the mind is ignorant may, by a figure of speech, be called unconscious Will; a phrase which would be a contradiction in terms if this word Will (which I write with a capital letter) were not used metaphorically. From this metaphor, when its boldness seems to be dulled by use, we may pass insensibly to giving the name of Will to that whole transcendental potency of the soul which, like the mainspring of a watch, lay coiled up tightly within it from the beginning of time. A man's transcendental Will can then be called the source of everything that ever happens to him—his birth, his character, his whole life, and his death—all that he most detests and most emphatically does not will, like his nightmares, being an expression of the original pregnancy of his spirit, and its transcendental principle of development.

There is but one thing to add touching a point often left by these philosophers in the most hopeless obscurity. In Leibniz the number of spirits was infinite: in the later systems they are reduced to one. This difference seems greater than it is, for when such terms as Spirit or Will are used metaphorically, standing for unconscious laws of continuity or development, and when the Will or Spirit present in me now may be said to have presided over the destinies of my soul infinite ages before I was born, there seems to be no good reason why the same Spirit or Will should not preside over all the inhabitants of the universe at all times, be they gods or humming-birds. Such a Spirit or Will resembles the notion of Providence, or the law of evolution, or the pre-established harmony of Leibniz far more than it resembles a mind. Those philosophers, intent on proving that the Spirit can be only one, might have proceeded, therefore, by urging that a Spirit was at best a formal and abstract law, covering such disparate facts, that all flesh and fowl, all demons and angels, might just as well be animated by a single Spirit. As it takes all sorts of things to make a world, it might take all sorts of things to express a Spirit.

This cool and consciously verbal way of making all one, however, is not the way of the Germans. No doubt in practice the unity of the Spirit or Will in their systems amounts to nothing more, yet their intention and illusion is rather that whenever two things can be called manifestations of one Spirit in the loosest and most metaphorical sense of this word they are thereby proved to be data in one spirit in the most intimate and psychological sense of the same. So that what really happens to transcendentalists is not that they unite all the transcendental units of Leibniz into one even looser transcendental unit, but that they limit the universe to what in Leibniz was one of an infinite number of parallel careers. Nay, they limit even that one career to the experience present at one point, that of the most intense and comprehensive self-consciousness.

The unity they desire and believe in is accordingly an actual and intense unity. All its elements are to be viewed at once, bound and merged together by the simultaneous intuition of all their relations, and this in a single, unchanging, eternal moment of thought, or rather of unutterable feeling. The union is, therefore, real, psychic, mystical, and so close that everything that was to be united there, by a curious irony, remains outside.