The causal interpretation of the object is, however, the more important, and is that which is chiefly emphasised by Kant. It is, indeed, simply a further and more adequate mode of expressing the substantial unity of the object. All the qualities must be causally bound up with one another in such a way that the nature of each is determined by the nature of all the others, and that if any one quality be changed all the others must undergo corresponding alterations. Viewed in this manner, in terms of the category of causality, an object signifies a necessitated combination of interconnected qualities or effects. But since no such form of _necessitation_ can be revealed in the manifold of sense, our _consciousness_ of compulsion cannot originate from without, and must be due to those _a priori_ forms which, though having their source within, control and direct our interpretation of the given. Though the objective compulsion is not itself due to the mind, our _consciousness_ of it has this mental _a priori_ source. The concept of an object consists in the thought of a manifold so determined in its specific order and groupings as to be interpretable in terms of the categories of substance and causality. But the problem of the deduction proper is not yet raised. On the one hand, Kant has defined what the concept of the objective must be taken as involving, and on the other, has pointed out that since the given as given is an unconnected manifold, any categories through which it may be interpreted must be of independent origin; but it still remains to be proved that the above is a valid as well as a possible mode of construing the given appearances. The categories, as _a priori_ concepts, originate from within. By what right may we assert that they not only relate to an object, but even constitute the very concept of it? Are appearances legitimately interpretable in any such manner? It was, we may believe, in the process of answering this question that Kant came to realise that the objects of our representations must no longer be regarded as things in themselves. For, as he finds, a solution is possible only on the further assumption that the mind is legislating merely for the world of sense-experience, and is making no assertion in regard to the absolutely and independently real. Kant’s method of proof is the transcendental, _i.e._ he seeks to demonstrate that this interpretation of the given is indispensably necessary as being a _sine qua non_ of its possible apprehension. This is achieved by means of the conclusion already established through the preliminary steps of the subjective deduction, namely, that all consciousness involves self-consciousness. Kant’s proof of the objective validity of the categories consists in showing that only by means of the interpretation of appearances as _empirically_ objective is self-consciousness possible at all.