But it seemed to him that the universals, the categories, must be considered in themselves and in their relation to each other, and not alone in relation to the concrete facts in which they are realised, if they are to be exhibited not as instruments which the finite mind uses but as moments or phases in a process which in its unity,Mind itself is. Just as the scientist takes a specific fact or set of facts by itself, not in order to find out what it is apart from its relations to other facts or sets of facts but in order to disclose those relations, so Hegel took the various categories— those of Being, Essence, Cause, etc.—each by itself, in order to show that it is not merely capable of being combined with the others, but that there is contained that within it which must of necessity lead on to the others, and develop into them. Any one category, that is to say, when conceived in isolation, reveals inher ent contradiction, passes over into its opposite—an opposition that is only overcome through both evincing themselves as ingre dients in a category higher than either of them. Then this again exhibits a similar logical movement, with the same result as before. And so on, through ever-widening ranges of differentiation and integration, until at length the whole system of thoughts is compassed and seen to constitute an organic unity, or Thought in its entirety.
In laying out what he took to be the intelligible framework of reality Hegel was not attempting to deduce concrete facts from the system of pure thought. He was attempting rather to show what the fundamental nature of reality is and not how every detail of the world exhibits that nature,—a task obviously in capable of fulfilment. But it was his view that could we discover what every detail was we should discern that it was a logical consequence of the ultimate ground. In other words, like Plato and Spinoza, he was identifying truth and real existence; he was saying that although we cannot deduce concrete fact from the universals of thought, yet in the long run it must be deducible therefrom. "In the Absolute truth and existence are one." We come here upon the fundamental problem in the theory of knowledge.
On the one hand, thought has been regarded as a purely sub jective procedure of the finite mind, and whatever contribution it may make towards clearing up and methodising the information we otherwise gather in respect to real existence, it does not in itself constitute the way in which real existence is manifested to us. Only through direct affection of ourselves in the form of
sensations can there be given us indubitable signs of actually existing things. And then the difficulty is that the world of real fact would seem to lie altogether beyond our ken,—at the best knowledge is knowledge of phenomena only, which can never be accurately described as knowledge of the real.
On the other hand, thought and reality are declared by Hegel to be identical, and since the principles involved in thought are the principles inherent in reality itself, the contents of logical thought must be the contents of reality. There can be no inter vening "ideas," in Locke's sense of the term, screening the real from our view. The difficulty here is that, since the contents of thought are characterised throughout by universality, there appear to be no means of retaining as real the concrete particulars of experience. To deduce the particular from the universal would seem to evince itself as a futile undertaking, because from the very nature of the original position assumed, it must be impossible to extract from the universal, that wherein the particular specifi cally differs from it. Something over and above what is contained in the universal must be possessed by the particular; and this residuum can never be accounted for by reference to the universal.
And one aspect of the antithesis is striking. The contents of thought, as universals, would seem to be independent of time and unaffected by change, whereas the realm of perceived fact pre sents itself as essentially temporal in character and as con stantly undergoing change. Certainly, the succession of categories in the Hegelian dialectic was not conceived as a temporal develop ment ; and, since the dialectic was regarded as the key to all reality, it is clear that reality was held to be timeless. Yet, in that case, the appearance of temporal succession and change calls for explanation, and all attempts hitherto made to furnish such explanation seem to be singularly unsuccessful. Naturally, then, in recent epistemological work, the general inquiry as to the rela tion in which the processes or results of thinking stand to the nature and relations of real existence has remained the central problem.