[Footnote 2: Within the knowledge of reason, as well as in experiential knowledge, a further distinction is made between primary truths (which need no proof) and derived truths. The highest truths of reason are the identical principles, which are self-evident; from these intuitive truths all others are to be derived by demonstration—proof is analysis and, as free from contradictions, demonstration. The primitive truths of experience are the immediate facts of consciousness; whatever is inferred from them is less certain than demonstrative knowledge. Nevertheless experience is not to be estimated at a low value; it is through it alone that we can assure ourselves of the reality of the objects of thought, while necessary truths guarantee only that a predicate must be ascribed to a subject (e.g., a circle), but make no deliverance as to whether this subject exists or not.]
To the broad and comprehensive tendency which is characteristic of Leibnitz's thinking, philosophy owes a further series of general laws, which all stand in the closest relation to one another and to his monadological and harmonistic principles, viz., the law of continuity, the law of analogy, the law of the universal dissimilarity of things or of the identity of indiscernibles, and, finally, the law of the conservation of force.
The most fundamental of these laws is the lex continui. On the one hand, it forbids every leap, on the other, all repetition in the series of beings and the series of events. Member must follow member without a break and without superfluous duplication; in the scale of creatures, as in the course of events, absolute continuity is the rule. Just as in the monad one state continually develops from another, the present one giving birth to the future, as it has itself grown out of the past, just as nothing persists, as nothing makes its entrance suddenly or without the way being prepared for it, and as all extremes are bound together by connecting links and gradual transitions,—so the monad itself stands in a continuous gradation of beings, each of which is related to and different from each. Since the beings and events form a single uninterrupted series, there are no distinctions of kind in the world, but only distinctions in degree. Rest and motion are not opposites, for rest may be considered as infinitely minute motion; the ellipse and the parabola are not qualitatively different, for the laws which hold for the one may be applied to the other. Likeness is vanishing unlikeness, passivity arrested activity, evil a lesser good, confused ideas simply less distinct ones, animals men with infinitely little reason, plants animals with vanishing consciousness, fluidity a lower degree of solidity, etc. In the whole world similarity and correspondence rule, and it is everywhere the same as here—between apparent opposites there is a distinction in degree merely, and hence, analogy. In the macrocosm of the universe things go on as in the microcosm of the monad; every later state of the world is prefigured in the earlier, etc. If, on the one side, the law of analogy follows as a consequence from the law of continuity, on the other, we have the principium (identitatis) indiscernibilium. As nature abhors gaps, so also it avoids the superfluous. Every grade in the series must be represented, but none more than once. There are no two things, no two events which are entirely alike. If they were exactly alike they would not be two, but one. The distinction between them is never merely numerical, nor merely local and temporal, but always an intrinsic difference: each thing is distinguished from every other by its peculiar nature. This law holds both for the truly real (the monads) and for the phenomenal world—you will never find two leaves exactly alike. By the law of the conservation of force, Leibnitz corrects the Cartesian doctrine of the conservation of motion, and approaches the point of view of the present day. According to Descartes it is the sum of actual motions, which remains constant; according to Leibnitz, the sum of the active forces; while, according to the modern theory, it is the sum of the active and the latent or potential forces—a distinction, moreover, of which Leibnitz himself made use.
We now turn from the formal framework of general laws, to the actual, to that which, obeying these laws, constitutes the living content of the world.
%2. The Organic World.%
A living being is a machine composed of an infinite number of organs. The natural machines formed by God differ from the artificial machines made by the hand of man, in that, down to their smallest parts, they consist of machines. Organisms are complexes of monads, of which one, the soul, is supreme, while the rest, which serve it, form its body. The dominant monad is distinguished from those which surround it as its body by the greater distinctness of its ideas. The supremacy of the soul-monad consists in this one superior quality, that it is more active and more perfect, and clearly reflects that which the body-monads represent but obscurely. A direct interaction between soul and body does not take place; there is only a complete correspondence, instituted by God. He foresaw that the soul at such and such a moment would have the sensation of warmth, or would wish an arm-motion executed, and has so ordered the development of the body-monads that, at the same instant, they appear to cause this sensation and to obey this impulse to move. Now, since God in this foreknowledge and accommodation naturally paid more regard to the perfect beings, to the more active and more distinctly perceiving monads than to the less perfect ones, and subordinated the latter, as means and conditions, to the former as ends, the soul, prior to creation, actually exercised an ideal influence—through the mind of God—upon its body. Its activity is the reason why in less perfect monads a definite change, a passion takes place, since the action was attainable only in this way, "compossible" with this alone.[1] The monads which constitute the body are the first and direct object of the soul; it perceives them more distinctly than it perceives, through them, the rest of the external world. In view of the close connection of the elements of the organism thus postulated, Leibnitz, in the discussions with Father Des Bosses concerning the compatibility of the Monadology with the doctrine of the Church, especially with the real presence of the body of Christ in the Supper, consented, in favor of the dogma, to depart from the assumption that the simple alone could be substantial and to admit the possibility of composite substances, and of a "substantial bond" connecting the parts of living beings. It appears least in contradiction with the other principles of the philosopher to assign the rôle of this vinculum substantiate to the soul or central monad itself.
[Footnote 1: Cf. Gustav Class, Die metaphysischen Voraussetzungen des
Leibnizischen Determinismus, Tübingen, 1874.]
Everything in nature is organized; there are no soulless bodies, no dead matter. The smallest particle of dust is peopled with a multitude of living beings and the tiniest drop of water swarms with organisms: every portion of matter may be compared to a pond filled with fish or a garden full of plants. This denial of the inorganic does not release our philosopher from the duty of explaining its apparent existence. If we thoughtfully consider bodies, we perceive that there is nothing lifeless and non-representative. But the phenomenon of extended mass arises for our confused sensuous perception, which perceives the monads composing a body together and regards them as a continuous unity. Body exists only as a confused idea in the feeling subject; since, nevertheless, a reality without the mind, namely, an immaterial monad-aggregate, corresponds to it, the phenomenon of body is a well-founded one (phenomenon bene fundatum). As matter is merely something present in sensation or confused representation, so space and time are also nothing real, neither substances nor properties, but only ideal things—the former the order of coexistences, the latter the order of successions.
If there are no soulless bodies, there are also no bodiless souls; the soul is always joined with an aggregate of subordinate monads, though not always with the same ones. Single monads are constantly passing into its body, or into its service, while others are passing out; it is involved in a continuous process of bodily transformation. Usually the change goes on slowly and with a constant replacement of the parts thrown off. If it takes place quickly men call it birth or death. Actual death there is as little as there is an actual genesis; not the soul only, but every living thing is imperishable. Death is decrease and involution, birth increase and evolution. The dying creature loses only a portion of its bodily machine and so returns to the slumberous or germinal condition of "involution", in which it existed before birth, and from which it was aroused through conception to development. Pre-existence as well as post-existence must be conceded both to animals and to men. Leuwenhoek's discovery of the spermatozoa furnished a welcome confirmation for this doctrine, that all individuals have existed since the beginning of the world, at least as preformed germs. The immortality of man, conformably to his superior dignity, differs from the continued existence of all monads, in that after his death he retains memory and the consciousness of his moral personality.
%3. Man: Cognition and Volition.%