The wide applicability of pre-established harmony might come home to its inventor as a rich surprise. The reflective historian will find it less surprising, for he will suspect that the applications were in view from the start. What was Leibniz thinking of when the new principle flashed upon him? What was he not thinking of? He had a many-sided mind. If the origins of the principle were complex, little wonder that its applications were manifold. Every expositor of Leibniz who does not wish to be endlessly tedious must concentrate attention on one aspect of Leibniz's principle, and one source of its origin. We will here give an account of the matter which, we trust, will go most directly to the heart of it, but we will make no claims to sufficient interpretation of Leibniz's thought-processes.
Leibniz, then, like all the philosophers of the seventeenth century, was reforming scholasticism in the light of a new physical science. The science was mathematical in its form, mechanistical in its doctrine, and unanswerable in its evidence—it got results. But it was metaphysically intractable, and the doctrines of infinite and finite substance which it generated furnish a gallery of metaphysical grotesques; unless we are to except Leibniz; his system is, if nothing else, a miracle of ingenuity, and there are moments when we are in danger of believing it.
It is a natural mistake for the student of seventeenth-century thought to underestimate the tenacity of scholastic Aristotelianism. Descartes, we all know, was reared in it, but then Descartes overthrew it; and he had done his work and died by the time that Leibniz was of an age to philosophize at all. We expect to see Leibniz starting on his shoulders and climbing on from there. We are disappointed. Leibniz himself tells us that he was raised in the scholastic teaching. His acquaintance with Descartes's opinions was second-hand, and they were retailed to him only that they might be derided. He agreed, like an amiable youth, with his preceptors.
The next phase of his development gave him a direct knowledge of Cartesian writings, and of other modern books beside, such as those of the atomist Gassendi. He was delighted with what he read, because of its fertility in the field of physics and mathematics; and for a short time he was an enthusiastic modern. But presently he became dissatisfied. The new systems did not go far enough, they were still scientifically inadequate. At the same time they went too far, and carried metaphysical paradox beyond the limits of human credulity.
There is no mystery about Leibniz's scientific objections to the new philosophers. If he condemned them here, it was on the basis of scientific thought and observation. Descartes's formulation of the laws of motion could, for example, be refuted by physical experiment; and if his general view of physical nature was bound up with it, then so much the worse for the Cartesian philosophy. But whence came Leibniz's more strictly metaphysical objections? Where had he learned that standard of metaphysical adequacy which showed up the inadequacy of the new metaphysicians? His own disciples might be satisfied to reply, that he learnt it from Reason herself; but the answer will not pass with us. Leibniz reasoned, indeed, but he did not reason from nowhere, nor would he have got anywhere if he had. His conception of metaphysical reason was what his early scholastic training had made it.
There are certain absurd opinions which we are sure we have been taught, although, when put to it, we find it hard to name the teacher. Among them is something of this sort. 'Leibniz was a scholarly and sympathetic thinker. He had more sense of history than his contemporaries, and he was instinctively eclectic. He believed he could learn something from each of his great predecessors. We see him reaching back to cull a notion from Plato or from Aristotle; he even found something of use in the scholastics. In particular, he picked out the Aristotelian "entelechy" to stop a gap in the philosophy of his own age.' What this form of statement ignores is that Leibniz was a scholastic: a scholastic endeavouring, like Descartes before him, to revolutionize scholasticism. The word 'entelechy' was, indeed, a piece of antiquity which Leibniz revived, but the thing for which it stood was the most familiar of current scholastic conceptions. 'Entelechy' means active principle of wholeness or completion in an individual thing. Scholasticism was content to talk about it under the name of 'substantial form' or 'formal cause'. But the scholastic interpretation of the idea was hopelessly discredited by the new science, and the scholastic terms shared the discredit of scholastic doctrine. Leibniz wanted a term with a more general sound. 'There is an X', he wanted to say, 'which scholasticism has defined as substantial form, but I am going to give a new definition of it.' Entelechy was a useful name for X, the more so as it had the authority of Aristotle, the master of scholasticism.
Under the name of entelechy Leibniz was upholding the soul of scholastic doctrine, while retrenching the limbs and outward flourishes. The doctrine of substantial form which he learnt in his youth had had something in it; he could not settle down in the principles of Descartes or of Gassendi, because both ignored this vital something. Since the requirements of a new science would not allow a return to sheer scholasticism, it was necessary to find a fresh philosophy, in which entelechy and mechanism might be accommodated side by side.
If one had asked any 'modern' of the seventeenth century to name the 'ancient' doctrine he most abominated, he would most likely have replied, 'Substantial form'. Let us recall what was rejected under this name, and why.
The medieval account of physical nature had been dominated by what we may call common-sense biology. Biology, indeed, is the science of the living, and the medievals were no more inclined than we are to endow all physical bodies with life. What they did do was to take living bodies as typical, and to treat other bodies as imperfectly analogous to them. Such an approach was a priori reasonable enough. For we may be expected to know best the physical being closest to our own; and we, at any rate, are alive. Why not argue from the better known to the less known, from the nearer to the more remote, interpreting other things by the formula of our own being, and allowing whatever discount is necessary for their degree of unlikeness to us?
Common-sense biology reasons as follows. In a living body there is a certain pattern of organized parts, a certain rhythm of successive motions, and a certain range of characteristic activities. The pattern, the sheer anatomy, is basic; but it cannot long continue to exist (outside a refrigerator) without accompanying vital rhythms in heart, respiration and digestion. Nor do these perform their parts without the intermittent support of variable but still characteristic activities: dogs not only breathe and digest, they run about, hunt their food, look for mates, bark at cats, and so on. The anatomical pattern, the vital rhythm, and the characteristic acts together express dogginess; they reveal the specific form of the dog. They reveal it; exactly what the specific form consisted in was the subject of much medieval speculation. It need not concern us here.
Taking the form of the species for granted, common-sense biology proceeds to ask how it comes to be in a given instance, say in the dog Toby. Before this dog was born or thought of, his form or species was displayed in each of his parents. And now it looks as though the form of dog had detached itself from them through the generative act, and set up anew on its own account. How does it do that? By getting hold of some materials in which to express itself. At first it takes them from the body of the mother, afterwards it collects them from a wider environment, and what the dog eats becomes the dog.
What, then, is the relation of the assimilated materials to the dog-form which assimilates them? Before assimilation, they have their own form. Before the dog eats the leg of mutton, it has the form given to it by its place in the body of a sheep. What happens to the mutton? Is it without remainder transubstantiated from sheep into dog? It loses all its distinctively sheep-like characteristicsm but there may be some more basically material characteristics which it preserves. They underlay the structure of the mutton, and they continue to underlie the structure of the dog's flesh which supplants it. Whatever these characteristics may be, let us call them common material characteristics, and let us say that they belong to or compose a common material nature.
The common material nature has its own way of existing, and perhaps its own principles of physical action. We may suppose that we know much or that we know little about it. This one thing at least we know, that it is capable of becoming alternatively either mutton or dog's flesh. It is not essential to it to be mutton, or mutton it would always be; nor dog's flesh, or it would always be dog's flesh. It is capable of becoming either, according as