Another consequence of Leibniz's treatment of the negative as merely limitative is that he can find no distinction, excepting of degree, between nature and spirit. Such a conception is undoubtedly in advance of the Cartesian dualism, which regards them as opposed realms _without_ any relation; but it may be questioned whether it is as adequate a view as that which regards them as distinct realms _on account_ of relation. At all events, it leads to confusion in Leibniz's treatment of both material objects and self-conscious personalities. In the former case his method of escape is a metaphor,--that objects apparently material are full of souls, or spirits. This may mean that the material is _merely_ material only when considered in implicit abstraction from the intelligence which conditions it, that the material, in truth, is constituted by some of the relations which in their completeness make up intelligence. This at least bears a consistent meaning. But it is not monadism; it is not the doctrine that matter differs from spirit only in degree: it is the doctrine that they differ in kind, as the conditioned from the conditioning. At times, however, Leibniz attempts to carry out his monadism literally, and the result is that he conceives matter as being itself endowed, in some unexplained way, with souls, or since this implies a dualism between matter and soul, of being made up, composed, of souls. But as he is obliged to explain that this composition is not spatial, or physical, but only ideal, this doctrine tends to resolve itself into the former. And thus we end where we began,--with a metaphor.