A Beginner's History of Philosophy, Vol. 2: Modern Philosophy

by Herbert Ernest Cushman

(1) His Early Classical Studies. The father of Leibnitz, who was a professor of moral philosophy at Leipsic, died when his son was young. Left much to himself, the boy spent his time in his father’s library. At eight years he had acquired Latin; at twelve he had read Seneca, Pliny, Quintilian, Herodotus, Xenophon, Cicero, Plato, the Roman historians, the Greek and Latin fathers. He became so absorbed in scholastic studies that his friends feared that he would not leave them, “not knowing that my mind could not be satisfied with only one kind of thing.” There can be noquestion that this scholastic training gave him a first hand and sympathetic appreciation of scholastic philosophy. The Aristotelian conception of cosmic purpose, which he got at this time, never left him. Among the writers of the Natural Science Period he alone returned to Aristotle. He made Aristotle’s teleological cause an integral part of his doctrine. His motto finally became, in his Theodicy, “Everything is best in this best of possible worlds.” While for a time he turned from Aristotle to Descartes, in his final construction of his theory he borrowed more from Aristotle.

(2) The New Science and His Own Discoveries. Leibnitz was more fortunate than many of his contemporaries in that his university had already included in its curriculum the study of mathematics. At the age of fifteen he was devoting himself to mathematics at Jena, and he said that the study of Kepler, Galileo, and Descartes made him feel as though “transported into a different world.” Later in life he said of himself, that at fifteen he had decided to give up the scholastic theory of Forms for the mathematical explanation of the world. He became acquainted with the theories of Hobbes and Gassendi in 1670, when he was at Mainz. In 1672, at the age of twenty-six, when he was in Paris, he made himself possessor of all that the celebrated circle of Parisian scientists had to teach. He had gone to Paris a dualist; he returned to his native land with the Aristotelian teleology side by side in his mind with the Spinozistic conception of identity and necessity, the Spinozistic method, and the mathematical theory of the significance of infinitely small particles. The next ten years (1676–1686) were spent in overcoming his own dualism by systematizing these new theories acquiredfrom so many sources. In 1680 he had universalized the concept of force so as to apply it to both souls and bodies. In 1684 he published his discovery of the differential calculus, in which he has had to share honors with Newton. In 1685 he asserted that the centres of force have individuality. He was led to this conclusion on account of the discovery of small organisms by the microscopes of Swammerdam and Leeuwenhoek. In 1686 he successfully organized his collected material into his final system, although it was not until eleven years later (1697) that he called these centres “monads.” Probably he got the term “monad” not from Bruno, but from the mystic chemist, Van Helmont.

Not only the content, but the form of his philosophy was determined by his mathematical studies. His philosophical diction is remarkably lucid. Mathematics reinforced his early resolve “in words to attain clearness and in matter usefulness.” His later discussions contain many terms that he had borrowed directly from mathematics.

(3) Political Pressure for Religious Reconciliation. When Frederick the Wise of Saxony in 1519 refused the crown of Emperor, Germany was thrown into internal strife that in one hundred and thirty years destroyed all its material wealth and depopulated the country. This terminated in the Thirty Years’ War (1618–1648) and the Peace of Westphalia. Leibnitz was born two years before peace was declared. He was the first German scientist in two hundred years. Both Catholics and Protestants were weary of strife, and there was a general movement toward religious reconciliation. Thus religious amity was the most urgent public question.

Pietism had been one of the movements in Germany during the recovery of the country from the Thirty Years’ War, and it represented the best side of German civilization at that time. It was a reaction on the one side against the mechanical theory of the scientists, and on the other against the destructive strife of the old and new confessions. The mother of Leibnitz was not only a Protestant, but also a Pietist, so that the subject of religion early formed an important part of her son’s training. When he entered the diplomatic service of the Elector of Mainz the question of religious reconciliation took practical form for him. No doubt his philosophy as a theory of reconciliation grew out of such practical issues, as they were presented to him at Mainz. Leibnitz had, therefore, a part in the religious reaction in Germany in the last of the seventeenth century, which aimed to reconcile the divergent interests of religion and science. He tried to effect this in no external way, by patching together irreconcilable elements, but in an internal way, by an examination of fundamental principles. With his early training, his theological reading, and his wide public experience, Leibnitz was fitted to take a prominent part in the movement for reconciliation.

The Method of Leibnitz. Although the philosophers who immediately followed Spinoza did not dare to accept his philosophical conclusions, they adopted his method. They united it with the syllogistic processes of formal logic for the deduction of all knowledge. This method became very prevalent, as is seen in the practices of the German Cartesians and in the preparation of academic text-books. Examples of this are Jung, Weigel, who was Leibnitz’s teacher, and Puffendorf,who tried to deduce by the geometrical method the entire system of natural right from a single principle of human need. In the next century Wolff used this method in writing his Latin text-books.

When this aspect of Spinoza’s teaching was gaining a foothold in Germany, Leibnitz came into sympathy with it through his teacher, Weigel, and at first was one of its most ardent supporters. In jest he showed by this geometrical, syllogistic method in sixty propositions that the Count Palatine of Neuberg must be elected King of the Poles. In seriousness he believed that all philosophical controversies would cease when philosophy should be stated like a mathematical calculation.

Hobbes’s theory of words as counters to be used in conceptual reckoning, the universal formulas of the Art of Lull and the pains which Bruno had taken for its improvement, the Cartesian belief that the geometrical method would prove to be an art of invention—all these were influences upon Leibnitz, that committed him to the method of Spinoza and made him pursue that method energetically. Leibnitz was part of the widespread movement of the time to form a Lingua Adamica—a universal language, which should discover fundamental philosophical conceptions and the logical operations of their combinations. In brief, Leibnitz hoped to form a philosophical calculus.

What, asked Leibnitz, are the highest truths which in their combination yield all knowledge? What are the truths, so immediately and intuitively certain, that they force themselves upon the mind as self-evident and thereby form the ground for the deduction of all knowledge? They are of two classes: (1) The universaltruths of the reason, and (2) The facts of experience. The truths of the reason are forever true; the facts of experience have a truth for that single instance. But both are true in themselves and not from deduction from anything else. They are “first truths,” for a thing is true if it can be deduced from the reason or tested as an experienced fact. The two kinds of truth are the rational or a priori, and the empirical or a posteriori. The difference between the starting point of the Rationalism of Leibnitz and the Enlightenment of Locke appears here. Locke said, “There is nothing in the mind that does not come from the senses.” “Except the mind itself and its operations,” added Leibnitz in comment.

But there is a difference between these two kinds of truth. The truths of the reason are clear and distinct; the truths of experience are clear but not distinct. Leibnitz is, be it observed, making a distinction between the two terms of the pet phrase of the Rationalists—“clear and distinct ideas.” He means that rational truth is so transparent that it is impossible to conceive its opposite; that empirical truth is only clear, and its opposite is thinkable. It is impossible to think that the three angles of a triangle equal anything but two right angles, but it is possible to think that its side, which is now two inches, may be four inches. Thus emerge the two logical principles upon which Leibnitz founded his philosophy: rational truths depend upon the Principle of Contradiction; empirical truths depend upon the Principle of Sufficient Reason. At first Leibnitz conceived that this distinction between truths did not apply to God, but only to man. Man must rejoice in the few rational truths in his possession andbe content with merely establishing the actuality of his experiences. The divine reason can, however, see the impossibility of the opposite both in rational and in empirical truth. Later on Leibnitz conceived the distinction between the two kinds of truth to be absolute. That is, in the nature of things the two truths differ. The rational truth has no opposite, but is a necessary truth; the empirical truth has an opposite, and is a contingent truth.