the soul to the body in such a way that the soul lets itself be inclined by the passions, which are born from corporeal representations. It is by its confused thoughts (sensations) that the soul represents the bodies about it,” just as, we may add, its distinct thoughts represent the monads or souls about it, and, in the degree of their distinctness, God, the monad which is purus actus.
Following the matter into more detail, we may say that since God alone is pure energy, knowing no limitation, God alone is pure spirit. Every finite soul is joined to an organic body. “I do not admit,” says Leibniz, “that there are souls entirely separate from matter, nor created spirits detached from body. . . . It is this body which the monad represents most distinctly; but since this body expresses the entire universe by the connection of all matter throughout it, the soul represents the entire universe in representing the body which belongs to it most particularly.” But according to the principle of continuity there must be in the least apparent portion of matter still “a universe of creatures, of souls, of entelechies. There is nothing sterile, nothing dead in the universe. It is evident from these considerations that every living body has a dominant entelechy, which is the soul in that body, but that the members of this living body are again full of other living beings and souls,” which, however, since not of so high a grade, that is, not representing the universe so fully, appear to be wholly material and subject to the “dominant” entelechy; namely, to the one which gives the law to the others by expressing more adequately the idea at which they only confusedly aim. Owing to the constant change of activity, however, these particles do not remain in constant subordination to the same entelechy (that is, do not form parts of the same body), but pass on to higher or lower degrees of “evolution,” and have their places taken by others undergoing similar processes of change. Thus “all bodies are in a perpetual flux, like rivers, with parts continually leaving and entering in.” Or, interpreting this figurative language, each monad is continually, in its process of development, giving law to new and less developed monads, which therefore appear as its body. The nature of matter in itself, and of its phenomenal manifestation in the body, are, however, subjects which find no explanation here, and which will demand explanation in another chapter.
We may sum up Leibniz’s theory of sensation by saying that it is a representative state developed by the self-activity of the soul; that in itself it is a confused or “involved” grade of activity, and in its relation to the world represents the confused or passive aspects of existence; that this limitation of the monad constitutes matter, and in its necessary connection with the monad constitutes the body which is always joined to the finite soul; that to this body are joined in all cases an immense number of monads, whose action is subordinate to that of this dominant monad, and that it is the collection of these which constitute the visible animal body. Thus if we look at sensation with regard to the monad which possesses it, it is a product of the body of the monad; if we look at it with reference to other monads, it represents or reflects their passive or material side. This is evidently one aspect again of the pre-established harmony,—an aspect in which some of the narrower of Leibniz’s critics have seen the whole meaning of the doctrine exhausted. It is, however, simply one of the many forms in which the harmony, the union of spiritual and mechanical, ideal and material, meets us. In truth, while in other systems the fact of sensation is a fact demanding some artificial mode of reconciling “mind” and “matter,” or is else to be accepted as an inexplicable fact, in the system of Leibniz it is itself evidence that the spiritual and the mechanical are not two opposed kinds of existence, but are organically united. It is itself the manifestation of the harmony of the ideal and the material, not something which requires that a factitious theory be invented for explaining their appearance of harmony. Sensation has within itself the ideal element, for it is the manifestation, in its most undeveloped form, of the spiritual meaning of the universe. It has a mechanical element, for it expresses the limitation, the passivity, of the monad.
It is from this standpoint that Leibniz criticises what Locke says about the relation of sensations to the objects which produce them. Leibniz holds that all our sensations have a definite and natural connection with the qualities of objects,—the “secondary” as well as the “primary.” They all represent certain properties of the object. Even the pain which the thrust of a needle gives us, while it does not resemble anything in the needle, does in some way represent or resemble motions going on in our body. This resemblance is not necessarily one of exact form, but just as the ellipse, hyperbola, and parabola are projections of the circle in the sense that there is a natural and fixed law of connection between them, so that every point of one corresponds by a certain relation with every point of the other, so the resemblance between the sensation and the quality of the object is always in the form of a fixed law of order, which, however unknown to us it may now be, is capable of being found out. If we are to make any distinction between “secondary” and “primary” sensations, it should be not that one presents qualities that are in the objects, and the other affections which exist only in us, but that the primary sensations (of number, form, size, etc.) represent the qualities in a distinct way, appealing to the rational activity of intelligence, while the secondary represent the qualities in a confused way, a way not going beyond the effect upon the mind into relations, that is, into distinct knowledge.
This brings regularly before us the question of the relation of sensations to knowledge. We have seen enough already to know that Leibniz does not believe that knowledge begins with the simple (that is, unrelated), and then proceeds by a process of compounding. The sensation is not simple to Leibniz, but thoroughly complex, involving confusedly within itself all possible relations. As relations are brought forth into distinct light out of this confusion, knowledge ends rather than begins with the simple. And again it is evident that Leibniz cannot believe that knowledge begins and ends in experience, in the sense in which both himself and Locke use the word; namely, as meaning the combination and succession of impressions.
“Experience,” as they use the term, consists in sensations and their association,—“consecution” as Leibniz calls it. Experience is the stage of knowledge reached by animals, and in which the majority of men remain,—and indeed all men in the greater part of their knowledge. Leibniz takes just the same position regarding the larger part of our knowledge which Hume takes regarding it all. It consists simply in associations of such a nature that when one part recurs there is a tendency to expect the recurrence of the other member. It resembles reason, but it is based on the accidental experience of events in a consecutive order, and not on knowledge of their causal connection. We all expect the sun to rise to-morrow; but with all of us, excepting the astronomer, such expectation is purely “empirical,” being based on the images of past experiences which recur. The astronomer, however, sees into the grounds, that is, the reasons, of the expectation, and hence his knowledge is rational.
Thus we have two grades of knowledge,—one empirical, consisting of knowledge of facts; the other rational, being of the truths of reason. The former is contingent and particular, the latter is necessary and universal. Leibniz insists, with a pertinacity which reminds us of Kant, that “experience” can give instances or examples only, and that the fact that anything has happened in a given way any number of times in the past, can give no assurance that it will continue to do so in the future. There is nothing in the nature of the case which renders its exact opposite impossible. But a rational truth is necessary, for its opposite is impossible, being irrational or meaningless. This may not always be evident in the case of a complex rational truth; but if it be analyzed into simpler elements, as a geometrical proposition into definitions, axioms, and postulates, the absurdity of its opposite becomes evident. Sensation, in conclusion, is the having of confused ideas,—ideas corresponding to matter. Experience is the association of these confused ideas, and their association according to their accidental juxtaposition in the life of the soul. It therefore is not only thoroughly sensible, but is also phenomenal. Its content is sensations; its form is contingent and particular consecution. Both form and content, accordingly, need to be reconstructed if they are to be worthy of the name of science or of knowledge. This is the position which Leibniz assumes as against the empiricist, Locke. The details of this reconstruction, its method and result, we must leave till we come in the course of the argument again to the subject of knowledge.
