[Spinoza] — the deepest, most original thinker to emerge from our people from the end of the Bible to the birth of Einstein.

Spinoza (1634-77) is the noblest and most lovable of the great philosophers. Intellectually, some others have surpassed him, but ethically he is supreme.

The Ethics is a book of concepts (the second kind of knowledge), but also of affects (the first kind) and percepts (the third kind) too. Thus the paradox in Spinoza is that he's the most philosophical of philosophers, the purest in some sense, but also the one who more than any other addresses non-philosophers and calls forth the most intense non-philosophical understanding. That is why absolutely anyone can read Spinoza, and be very moved, or see things quite differently afterward, even if they can hardly understand Spinoza's concepts. Conversely, a historian of philosophy who understands only Spinoza's concepts doesn't fully understand him.

I read Spinoza's Ethics for the first time when I was thirteen years old. Of course at school we studied the Bible – which for me is the ultimate philosophical work. However, reading Spinoza opened up a new dimension for me, which is the reason for my continuing dedication to his works. Spinoza's simple principle 'man thinks' has become an existential mindset for me; my copy of his Ethics has become dog-eared and torn. For years I took it with me on my travels and in hotel rooms or intervals in concerts became absorbed by many of its principles. Spinoza's Ethics is the best training ground for the intellect, above all because Spinoza teaches the radical freedom of thought more completely than any other philosopher. This Spinozan brand of freedom is not a release from discipline into arbitrariness of thought, but an active process. The more one is able to determine one's own thoughts – in fact, causing one's own thoughts, thereby creating one's own experience of reality – the more it is possible to become self-determined, to be truly free.

...Spinoza was the philosopher who knew full well that immanence was only immanent to itself and therefore that it was a plane traversed by movements of the infinite, filled with intensive ordinates. He is therefore the prince of philosophers. Perhaps he is the only philosopher never to have compromised with transcendence and to have hunted it down everywhere. In the last book of the Ethics he produced the movement of the infinite and gave infinite speeds to thought in the third kind of knowledge. There he attains incredible speeds, with such lightning compressions that one can only speak of music, of tornadoes, of wind and strings. He discovered that freedom exists only within immanence. He fulfilled philosophy because he satisfied its prephilosophical presupposition. [...] Spinoza is the vertigo of immanence from which so many philosophers try in vain to escape. Will we ever be mature enough for a Spinozist inspiration?

There is no other philosophy than that of Spinoza.

It is true that God is necessity, or, as we may also put it, that he is the absolute Thing: he is however no less the absolute Person. That he is the absolute Person however is a point which the philosophy of Spinoza never reached: and on that side it falls short of the true notion of God which forms the content of religious consciousness in Christianity. Spinoza was by descent a Jew; and it is upon the whole the Oriental way of seeing things, according to which the nature of the finite world seems frail and transient, that has found its intellectual expression in his system. This Oriental view of the unity of substance certainly gives the basis for all real further development. Still it is not the final idea. It is marked by the absence of the principle of the Western world, the principle of individuality, which first appeared under a philosophic shape, contemporaneously with Spinoza, in the Monadology of Leibnitz.

As regards the philosophy of Spinoza, it is very simple, and on the whole easy to comprehend; the difficulty which it presents is due partly to the limitations of the method in which Spinoza presents his thoughts, and partly to his narrow range of ideas, which causes him in an unsatisfactory way to pass over important points of view and cardinal questions. Spinoza's system is that of Descartes made objective in the form of absolute truth. The simple thought of Spinoza's idealism is this: The true is simply and solely the one substance, whose attributes are thought and extension or nature: and only this absolute unity is reality, it alone is God. It is, as with Descartes, the unity of thought and Being, or that which contains the Notion of its existence in itself. The Cartesian substance, as Idea, has certainly Being included in its Notion; but it is only Being as abstract, not as real Being or as extension (supra, p. 241). With Descartes corporeality and the thinking 'I' are altogether independent Beings; this independence of the two extremes is done away with in Spinozism by their becoming moments of the one absolute Being. This expression signifies that Being must be grasped as the unity of opposites; the chief consideration is not to let slip the opposition and set it aside, but to reconcile and resolve it. Since then it is thought and Being, and no longer the abstractions of the finite and infinite, or of limit and the unlimited, that form the opposition (supra, p. 161), Being is here more definitely regarded as extension; for in its abstraction it would be really only that return into itself, that simple equality with itself, which constitutes thought (supra, p. 229). The pure thought of Spinoza is therefore not the simple universal of Plato, for it has likewise come to know the absolute opposition of Notion and Being.

Spinoza is the clear and luminous side of Modern philosophy. He is the negation of bourgeois mediation and of all the logical, metaphysical, and juridical fictions that organize its expansion. He is the attempt to determine the continuity of the revolutionary project of humanism. With Spinoza, philosophy succeeds for the first time in negating itself as a science of mediation. In Spinoza there is the sense of a great anticipation of the future centuries; there is the intuition of such a radical truth of future philosophy that it not only keeps him from being flattened onto seventeenth-century thought but also, it often seems, denies any confrontation, any comparison. Really, none of his contemporaries understands him or refutes him.

I do not have the professional knowledge to write a scholarly article about Spinoza. But what I think about this man I can express in a few words. Spinoza was the first to apply with strict consistency the idea of an all-pervasive determinism to human thought, feeling, and action. In my opinion, his point of view has not gained general acceptance by all those striving for clarity and logical rigor only because it requires not only consistency of thought, but also unusual integrity, magnamity, and — modesty.

Spinoza used the terminology of Descartes, and also published an account of his system. For we find the first of Spinoza's works entitled “An Exposition according to the geometrical method of the principles of the Cartesian philosophy.” Some time after this he wrote his Tractatus theologico-politicus, and by it gained considerable reputation. Great as was the hatred which Spinoza roused amongst his Rabbis, it was more than equalled by the odium which he brought upon himself amongst Christian, and especially amongst Protestant theologians — chiefly through the medium of this essay. It contains his views on inspiration, a critical treatment of the books of Moses and the like chiefly from the point of view that the laws therein contained are limited in their application to the Jews. Later Christian theologians have written critically on this subject, usually making it their object to show that these books were compiled at a later time, and that they date in part from a period subsequent to the Babylonian captivity; this has become a crucial point with Protestant theologians, and one by which the modern school distinguishes itself from the older, greatly pluming itself thereon. All this, however, is already to be found in the above-mentioned work of Spinoza. But Spinoza drew the greatest odium upon himself by his philosophy proper, which we must now consider as it is given to us in his Ethics. While Descartes published no writings on this subject, the Ethics of Spinoza is undoubtedly his greatest work; it was published after his death by Ludwig Mayer, a physician, who had been Spinoza's most intimate friend. It consists of five parts; the first deals with God (De Deo). General metaphysical ideas are contained in it, which include the knowledge of God and nature. The second part deals with the nature and origin of mind (De natura et origine mentis). We see thus that Spinoza does not treat of the subject of natural philosophy, extension and motion at all, for he passes immediately from God to the philosophy of mind, to the ethical point of view; and what refers to knowledge, intelligent mind, is brought forward in the first part, under the head of the principles of human knowledge. The third book of the Ethics deals with the origin and nature of the passions (De oriqine et natura affectuum); the fourth with the powers of the same, or human slavery (De servitute humana seu de affectuum viribus); the fifth, lastly, with the power of the understanding, with thought, or with human liberty (De potentia intellectus seu de libertate humana). Kirchenrath Professor Paulus published Spinoza's works in Jena; I had a share in the bringing out of this edition, having been entrusted with the collation of French translations.

Schelling calls Spinoza "the first philosopher who found the concepts whereby all the following centuries have grasped and fixed the two extremities of our knowing mind." For Lessing and Herder philosophy and Spinozism were identical; and the same statement was also made by Hegel, the most comprehensive and systematic, as well as the most independent and firm, among the German philosophers, who did not attempt, like Leibnitz, Fichte or Schelling, to reshape again and again his original-philosophy. And Hegel also said, "either you have Spinozism or you have no philosophy!"

Spinoza's ethical views are inextricably intertwined with his metaphysics, and it may be doubted whether his metaphysics is as good as is supposed by followers of Hegel. But the general attitude towards life and the world which he inculcates does not depend for its validity upon a system of metaphysics. He believes that all human ills are to be cured by knowledge and understanding; that only ignorance of what is best makes men think their interests conflicting, since the highest good is knowledge, which can be shared by all. But knowledge, as he conceives it, is not mere knowledge as it comes to most people; it is “intellectual love,” something coloured by emotion through and through. This conception is the key to all his valuations.

...Now Spinoza, my master and model in respect to the first point [the natural basis of morality], does not satisfy me on the second [the humane possibilities, the "types of excellence towards which life may be directed"]; and I will take this opportunity, since I may not have any other, of clearing my conscience of ambiguity in that respect. The complete moralist must not only be sound in physics, but must be inwardly inspired by a normal human soul and an adequate human tradition; he must be a complete humanist in a complete naturalist. Spinoza was not only a complete naturalist but, by a rare combination, also a spiritual man, seeing and accepting the place of the human heart in the universe; accepting it not grudgingly or viciously or frivolously, as your worldling does, but humbly and joyously: humbly in that he asked to be nothing more than he was, and joyously because what he was allowed him, in spirit, to salute and to worship every form of the good. Nevertheless, Spinoza was not a complete humanist. He had no idea of human greatness and no sympathy with human sorrow. His notion of the soul was too plebeian and too quietistic. He was a Jew not of Exodus or Kings but of Amsterdam. He was too Dutch, too much the merchant and artisan, with nothing of the soldier, the poet, the prince, or the lover. [...] He was virtuous but not normal. [...] He was a genius; but as a guide in the spiritual life, he was narrow and inadequate.