But Spinoza does not demonstrate how these two are evolved from the one substance, nor does he prove why there can only be two of them. Neither are extension and thought anything to him in themselves, or in truth, but only externally; for their difference is a mere matter of the understanding, which is ranked by Spinoza only among affections (Eth. P. I. Prop. XXXI. Demonst. p. 62), and as such has no truth. This has in recent times been served up again by Schelling in the following form: In themselves, the intelligent world and the corporeal world are the same, only under different forms; so that the intelligent universe is in itself the whole absolute divine totality, and the corporeal universe is equally this same totality. The differences are not in themselves, but the different aspects from which the Absolute is regarded are matters external to it. We take a higher tone in saying that nature and mind are rational; but reason is for us no empty word, for it means the totality which develops itself within itself. Again, it is the standpoint of reflection to regard aspects only, and nothing in itself. This defect appears in Spinoza and Schelling in the fact that they see no necessity why the Notion, as the implicit negative of its unity, should make a separation of itself into different parts; so that out of the simple universal the real, the opposed, itself becomes known. Absolute substance, attribute and mode, Spinoza allows to follow one another as definitions, he adopts them ready-made, without the attributes being developed from the substance, or the modes from the attributes. And more especially in regard to the attributes, there is no necessity evident, why these are thought and extension in particular.