Our starting-point, therefore, for the consideration of matter is the statement that it is receptivity, the capacity for being affected, which always constitutes matter. But what is meant by "receptivity"? To answer this question we must return to what was said about the two activities of the monad,--representation, or perception, and appetition,--and to the difference between confused and distinct ideas. The monad has appetition so far as it determines itself from within to change, so far as it follows an internal principle of energy. It is representative so far as it is determined from without, so far as it receives impressions from the universe. Yet we have learned to know that in one sense everything occurs from the spontaneity of the monad itself; it receives no influence or influxus from without; everything comes from its own depths, or is appetition. But, on the other hand, all that which so comes forth is only a mirroring or copying of the universe. The whole content of the appetition is representation. Although the monad works spontaneously, it is none the less determined in its activities to produce only reflections or images of the world. In this way appetition and representation appear to be identical. The monad is determined from within, indeed, but it is determined to exactly the same results as if wholly determined from without. What light, then, can be thrown from this distinction upon the nature of matter? None, unless we follow Leibniz somewhat farther. If we do, we shall see that the soul is regarded as appetitive, or self-active, so far as it has clear and distinct ideas. If the monad reaches distinct consciousness, it has knowledge of self,--that is, of the nature of pure spirit,--or, what again is equivalent to this, of the nature of reality as it universally is. Such knowledge is knowledge of God, of substance, of unity, of pure activity, and of all the innate ideas which elevate the confused perceptions of sense into science. Distinct consciousness is therefore equivalent to self-activity, and this to recognition of God and the universal. But if knowledge is confused, it is not possible to see it in its relations to self; it cannot be analyzed; the rational or ideal element in it is concealed from view. In confused ideas, therefore, the soul appears to be passive; being passive, to be determined from without. This determination from without is equivalent to that which is opposed to spirit or reason, and hence appears as matter. Such is in outline the Leibnizian philosophy.