§ 2.

That which knows all things and is known by none is the subject. It is accordingly the supporter of the world, the universal condition of all that appears, of all objects, and it is always presupposed; for whatever exists, exists only for the subject. Everyone finds himself as this subject, yet only in so far as he knows, not in so far as he is object of knowledge. But his body is already object, and therefore from this point of view we call it representation. For the body is object among objects and is subordinated to the laws of objects, although it is immediate object.12 Like all objects of perception, it lies within the forms of all knowledge, in time and space through which there is plurality. But the subject, the knower never the known, does not lie within these forms; on the contrary, it is always presupposed by those forms themselves, and hence neither plurality nor its opposite, namely unity, belongs to it. We never know it, but it is precisely that which knows wherever there is knowledge.

Therefore the world as representation, in which aspect alone we are here considering it, has two essential, necessary, and inseparable halves. The one half is the object, whose forms are space and time, and through these plurality. But the other half, the subject, does not lie in space and time, for it is whole and undivided in every representing being. Hence a single one of these beings with the object completes the world as representation just as fully as do the millions that exist. And if that single one were to disappear, then the world as representation would no longer exist. Therefore these halves are inseparable even in thought, for each of the two has meaning and existence only through and for the other; each exists with the other and vanishes with it. They limit each other immediately; where the object begins, the subject ceases. The common or reciprocal nature of this limitation is seen in the very fact that the essential, and hence universal, forms of every object, namely space, time, and causality, can be found and fully known, starting from the subject, even without the knowledge of the object itself, that is to say, in Kant’s language, they reside a priori in our consciousness. To have discovered this is one of Kant’s chief merits, and it is a very great one. Now in addition to this, I maintain that the principle of sufficient reason is the common expression of all these forms of the object of which we are a priori conscious, and that therefore all that we know purely a priori is nothing but the content of that principle and what follows therefrom; hence in it is really expressed the whole of our a priori certain knowledge. In my essay On the Principle of Sufficient Reason I have shown in detail how every possible object is subordinate to it, that is to say, stands in a necessary relation to other objects, on the one hand as determined, on the other as determining. This extends so far that the entire existence of all objects, in so far as they are objects, representations, and nothing else, is traced back completely to this necessary relation of theirs to one another, consists only in that relation, and hence is entirely relative; but more of this later. I have further shown that this necessary relation, expressed in general by the principle of sufficient reason, appears in other forms corresponding to the classes into which objects are divided according to their possibility; and again that the correct division of those classes is verified by these forms. Here I constantly assume that what was said in that essay is known and present to the reader, for had it not already been said there, it would have its necessary place here.