THE PHILOSOPHY OF SPINOZA AND LEIBNIZ. 349 explicitly recognised by Leibniz, without being thoroughly thought out. His " system " is not all-inclusive. The world is not the one system of reality, but "the best of all pos- sible worlds ". The elements of which it is composed are essentially " possibles," in their own nature completely independent. Thus the world is the system of the " corn- possible," resting on the chaos of the " possible ". The results of this general argument cannot be worked out within the limits of this paper, but I may take up one or two special points. (1) In the first place, as most closely con- nected with the general line of thought we have been following, let us consider the views of Descartes, Spinoza and Leibniz regarding extension and motion. According to Descartes, extension and motion are absolutely given. Ex- tension is a created substance, in the sense that its existence presupposes nothing else except the concours ordinaire of God. Motion is also a direct creation of " God Himself, who in the beginning created matter along with motion and rest and now, by His concours ordinaire alone, preserves in the whole the same amount of motion and rest that He then placed in it ". 1 From the combination of these two absolutely given elements given in separation from one another Descartes in his Principia, part iii., tries to show that the whole material world in its endless variety comes into being. Ultimately, then, all matter is space of three dimensions plus motion. Spinoza, excluding the idea of creation, reduces the independ- ence of extension, treating it not as substance but as an attribute of substance, i.e., as something which on the one hand is not relative to anything else except understanding, while on the other hand, being relative to understanding, it is not substance itself. This attribute of extension, however, is not what we call space of three dimensions, for it is one and indivisible. 2 In short, extension, for Spinoza, is that which is presupposed in extended things, that which remains when all the limits (the finitude) of extended things are thought away. And thus, of course, Spinoza rejects the view of Descartes that the essence of matter or corporeal substance can be an extension that is divisible. Divisible extension is extension conceived " abstractly or superficially, as by means of the senses we have it in the imagination ". 3 1 Principia, ii., 36. 2 Extended substance, according to Spinoza, can have no parts ; for if it had parts, each of them would be a substance and would be finite, which is a contradiction of the nature of substance as that which is infinite inasmuch as the conception of it requires the conception of nothing else ; cf. Ep. 12, Van Vloten (29 Bruder).
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