There is an old tradition that it is the faculty of thought which separates men from beasts; and to this tradition we shall adhere. In accordance with this, what man has, as being nobler than a beast, he has through thinking. Everything which is human, however it may appear, is so only because the thought contained in it works and has worked. But thought, although it is thus the essential, substantial, and effectual, has many other elements. We must, however, consider it best when Thought does not pursue anything else, but is occupied only with itself - with what is noblest -when it has sought and found itself. The history which we have before us is the history of Thought finding itself, and it is the case with Thought that it only finds itself in producing itself; indeed, that it only exists and is actual in finding itself. These productions are the philosophic systems; and the series of discoveries on which Thought sets out in order to discover itself, forms a work which has lasted twenty-five hundred years.
If the Thought which is essentially Thought, is in and for itself and eternal, and that which is true is contained in Thought alone, how, then, does this intellectual world come to have a history? In history what appears is transient, has disappeared in the night of the past and is no more. But true, necessary thought - and it is only with such that we have to do - is capable of no change. The question here raised constitutes one of those matters first to be brought under our consideration.
But in the second place, there are also many most important things outside of Philosophy, which are yet the work of Thought, and which are left unconsidered. Such are Religion, Political History, forms of Government, and the Arts and Sciences. The question arises as to how these operations differ from the subject of consideration, and how they are related in history? As regards these two points of view, it is desirable to show in what sense the history of Philosophy is here taken, in order to see clearly what we are about. Moreover, in the third place, we must first take a general survey before we descend to particulars, else the whole is not seen for the mere details-the wood is not seen for the trees, nor Philosophy for mere philosophies. We require to have a general idea of the nature and aim of the whole in order to know what to look for. Just as we first desire to obtain a general idea of a country, which we should no longer see in going into detail, so we desire to see the relation which single philosophies bear to the whole; for in reality, the high value of the detail lies in its relation to the whole. This is nowhere more the case than with Philosophy, and also with its history. In the case of a history, indeed, the establishment of the Universal seems to be less needful than in that of one of the sciences proper. For history seems at first to be a succession of chance events, in which each fact stands isolated by itself, which has Time alone as a connecting-link. But even in political history we are not satisfied with this. We see, or at least divine in it, that essential connection in which the individual events have their place and relation to an end or aim, and in this way obtain significance. For the significant in history is such only through its relation to and connection with a Universal. To perceive this Universal is thus to apprehend the significance.
There are, therefore, the following points with which I wish to deal in this introduction.
The first of these will be to investigate the character of the history of Philosophy, its significance, its nature, and its aim, from which will follow inferences as to its treatment. In particular, we shall get an insight into the relation of the history of Philosophy to the science of Philosophy, and this will be the most interesting point of all. That is to say, this history represents, not merely the external, accidental, events contained within it, but it shows how the content, or that which appears to belong to mere history, really belongs to the science of Philosophy. The history of Philosophy is itself scientific, and thus essentially becomes the science of Philosophy.
In the second place, the Notion of Philosophy must be more adequately determined, and from it must be deduced what should be excluded from the history of Philosophy out of the infinite material and the manifold aspects of the intellectual culture of the nations. Religion, certainly, and the thoughts contained in and regarding it, particularly when these are in the form of mythology, are, on account of their matter, and the sciences with their ideas on the state, duties and laws, on account of their form, so near Philosophy that the history of the science of Philosophy threatens to become quite indefinite in extent. It might be supposed that the history of Philosophy should take account of all these ideas. Has not everything been called Philosophy and philosophising? On the one hand, the close connection has to be further considered in which Philosophy stands with its allied subjects, religion, art, the other sciences, and likewise with political history. On the other hand, when the province of Philosophy has been correctly defined, we reach, with the determination of what Philosophy is and what pertains to it, the starting-point of its history, which must be distinguished from the commencements of religious ideas and mere thoughtful conjectures.
