=Three Central Problems in Spinoza’s Teaching.= We have already noted that Spinoza was the chief exponent of “clearness and distinctness” in this epoch when all mysteries were to be revealed. He sought to articulate a metaphysics that would spread out the plan of the world like a demonstration in geometry. His definition of substance is perfectly intelligible; he accepted the mathematical analysis of the material world into a world of extension, and that of the world of conscious states into one of thought――all this for the sake of simplification and clearness. How simple such a philosophy at the first blush appears――the world is God and his modifications. As a matter of fact it is one of the many examples of the irony of history that the philosophy of Spinoza is one of the most difficult to interpret. Its difficulties do not arise from its having a novel point of view, for on the contrary it is one that appeals strongly to the popular imagination. Its difficulties arise from its very simplicity, for, after all, human life is so rich and varied that a simple formula will hardly express it. From beginning to end Spinoza’s thought has a vagueness for which the beginner in vain strives to find the cause. The cause lies in the seemingly simple principle that God is all that really exists, and yet the world consists of God and other things. From Spinoza’s effort to simplify matters emerged three central problems: (1) The problem of the all-inclusiveness of God――the problem of pantheism; (2) The problem of the unity of God――the problem of mysticism; (3) The problem of the salvation of man――an ethical problem. We shall now consider these problems in order. =The Pantheism of Spinoza――The All-Inclusiveness of God.= That Spinoza’s philosophy is a pantheism appears at the outset in his conception of substance; for the substance is all that really is. Descartes had conceived of three substances,――God as the absolute substance, and mind and matter as the two relative substances. But to Spinoza there can be only one substance; for if there were two or more, no one would be substance, since each would be conceived through the others. If we think at all, we must think of substance as all-inclusive. One might suppose that this preliminary statement would be all that Spinoza could say about life: all that really is, is substance; other things do not exist. But that would be a misinterpretation of Spinoza. He does not mean that finite things are mere nothings. They exist as unrealities; they exist as negations of the substance. If you prick into the finite world, it does not collapse, like a balloon. It still exists as an unreality.