has been convinced that man needs knowledge more than anything else in the world, that knowledge is the only source of truth, and especially—I emphasize this particularly and insist upon it—that knowledge furnishes us with universal and necessary truths which embrace all being, truths from which man cannot escape and from which there is consequently no need to escape. Leibniz said that the “eternal truths” are not content to constrain but do something still more important: they “persuade.” And it is not, of course, only Leibniz personally whom they persuade but all men; Leibniz would not have ascribed any value to truths capable of persuading him but incapable of persuading others or even of constraining them.
In this respect there is hardly any difference between Leibniz and Kant. The latter has told us that reason avidly aspires to necessary and universal judgments. It is true that, in the case of Kant, the element of constraint seems to play a decisive and definitive role: even if there should be men whom the truths do not persuade, whom they irritate as experience irritates Kant, this would be no great misfortune; the truths would nevertheless constrain them and thus fully succeed in justifying themselves. And, in the last analysis, does not constraint persuade? In other words, truth is truth so long as it has demonstrative proofs at its disposal. As for indemonstrable truths, no one has any need of them and they appear to be incapable of persuading even a Leibniz.
It is this that determines Kant’s attitude towards metaphysics. It is known that according to Kant, who speaks of this more than once in his Critique of Reason, metaphysics has as its object three problems—God, the immortality of the soul, and freedom. But suddenly it appears that the final result of the Kantian critique is that none of these three metaphysical truths is demonstrable and that there can be no scientific metaphysics. One would have thought that such a discovery would have shaken Kant’s soul to its deepest foundations. But it did nothing of the sort. In his Preface to the Second Edition of The Critique of Pure Reason, Kant declares calmly, almost solemnly: “I had to renounce knowledge (Wissen) in order to make room for faith (Glauben).” So Kant speaks in this same Preface, where we read the following lines: “It will always be a scandal for philosophy and human reason in general that we must accept the existence of things outside ourselves merely on faith3 and that, if someone should take it into his head to doubt it, we would be incapable of setting before him any sufficient proof.” It is impossible to prove the existence of God, the immortality of the soul, or free will, but there is nothing offensive or disturbing in this either for philosophy or for human reason; all these will get along without proof and will content themselves with faith, with what Kant and everyone call faith. But when it is a question of the existence of objects outside ourselves, then faith does not suffice, then it is absolutely necessary to have proof. And yet, if one admits Kant’s point of departure, the existence of objects outside ourselves is hardly in a more enviable situation, as far as proof is concerned, than God, the immortality of the soul, or free will. At best, the existence of objects outside ourselves can be postulated or be an object of faith. But it is this that Kant cannot endure, just as Leibniz could not endure Descartes’ mountain without a valley. And Kant, not having at his disposal any convincing demonstration, just like Leibniz, did not recoil before the use of an argumentum ad hominem, before indignation: if we do not succeed in knowing that things exist outside ourselves, then philosophy and reason are forever covered with shame; it is a “scandal! . . .”
Why did Leibniz so passionately defend his eternal truths, and why was be so horrified at the idea of subordinating them to the Creator? Why did Kant take to heart the fate of objects outside ourselves, while the fate of God, of the soul and of freedom left him untouched? Is it not just the opposite which should have happened? The “scandal” of philosophy, one would think, consists in the impossibility of proving the existence of God. One would also think that the dependence of God on the truths would poison man’s mind and fill it with horror. So one would think; but in reality it was the contrary of this that occurred. Reason, which aspires eagerly to necessity and universality, has obtained all that it wished and the greatest representatives of modern philosophy have expelled everything which could irritate reason to the region of the “supra-sensible” from which no echo comes to us and where being is confounded with non-being in a dull and dreary indifference.
Even before The Critique of Pure Reason Kant wrote to Marcus Herz that “in the determination of the origin and validity of our knowledge the deus ex machina is the greatest absurdity that one could choose.” Then, as if he were translating Leibniz’s objections to Descartes: “To say that a supreme being has wisely introduced into us such ideas and principles (i.e., the eternal truths) is completely to destroy all philosophy.” It is on this that all of the critical philosophy, just like the pre-critical philosophy, is built. Reason does not tolerate the idea of what Kant calls a deus ex machina4 or “a supreme being”; this idea marks the end of all philosophy for reason. Kant could not forgive Leibniz for his modest “pre-established harmony” because it conceals a deus ex machina. For once one accepts the existence of a deus ex machina—this is to say, a God who, even though from afar and only from time to time, intervenes in the affairs of the world—reason would be obliged to renounce forever the idea that what is is necessarily just as it is, or, to use Spinoza’s language, that “things could not have been produced by God in any other way or order than that in which they were produced.”
Kant (in this, also, agreeing with Leibniz) was very unhappy when he was compared with Spinoza. He, like Leibniz, wanted people to consider him (and they did indeed consider him) a Christian philosopher. But for all his piety, he could not accept the idea that God can and must be placed above the truths, that God can be sought and found in our world. Why was this idea unacceptable to him? And why, when he spoke of the “dogmatic slumber” from which his “critiques” had permitted him to escape, did it not occur to him to ask whether the certitude with which he affirmed the autonomy of the truth, as well as his hatred for “experience,” did not flow from the “dogma” of the sovereignty of reason, a dogma devoid of all foundation and one which is an indication not of slumber but of profound sleep, or even—perhaps—the death of the human spirit? It is a terrible thing to fall into the hands of the living God. But to submit to impersonal Necessity which (no one knows how) has been introduced into being—this is not at all terrible, this calms and even rejoices! But then, why did Kant need to distinguish himself from Leibniz, and why did both Kant and Leibniz need to distinguish themselves from Spinoza? And why, I ask once more, do the historians of philosophy—one might almost say, does the history of philosophy—continue up to our own day to guard so carefully that boundary which Kant drew between himself and his immediate predecessors, between his philosophy, on the one hand, and the medieval and ancient philosophy, on the other hand? His “critiques,” in fact, have not at all shaken the foundations on which the investigative thought of European man has rested. After Kant, as before Kant, the eternal truths continue to shine above our heads like fixed stars; and it is through these that weak mortals, thrown into the infinity of time and space, always orient themselves. Their immutability confers upon them the power of constraint, and also—if Leibniz is to be believed—the power of persuading, of seducing, of attracting us to themselves, no matter what they bring us or what they demand of us, while the truths of experience, whatever they may bring, always irritate us, just as does the “supreme being” (that is to say, deus ex machina) even when he wisely introduces into us eternal truths concerning what exists and what does not exist.
II
The critical philosophy did not overthrow the fundamental ideas of Spinoza; on the contrary, it accepted and assimilated them. The Ethics and the Tractatus Theologico-Politicus remain alive, though implicitly, in the thought of German idealism quite as much as in the thought of Leibniz: the Necessity which determines the structure and order of being, the ordo et connexio rerum, does not constrain us but persuades us, draws us along, seduces us, rejoices us, and bestows upon us that final contentment and that peace of soul which at all times have been considered in philosophy as the supreme good. “Contentment with one’s self can spring from reason, and that contentment which springs from reason is the highest possible.”5 Men have imagined,
