All consciousness must in the first instance present itself as a relation between two constituent parts, the person who is conscious, and the thing, whatever it may be, of which he is conscious. This contrast has been indicated, directly or indirectly, by various names--mind and matter; person and thing; subject and object; or, lastly, in the distinction, most convenient for philosophy, however uncouth in sound, between self and not self--the _ego_ and the _non-ego_. In order to be conscious at all, I must be conscious of something: consciousness thus presents itself as the product of two factors, _I_ and _something_. The problem of the unconditioned is, briefly stated, to reduce these two factors to one. For it is manifest that, so long as they remain two, we have no unconditioned, but a pair of conditioned existences. If the _something_ of which I am conscious is a separate reality, having qualities and modes of action of its own, and thereby determining, or contributing to determine, the form which my consciousness of it shall take, my consciousness is thereby conditioned, or partly dependent on something beyond itself. It is no matter, in this respect, whether the influence is direct or indirect--whether, for instance, I see a material tree, or only the mental image of a tree. If the nature of the thing in any degree determines the character of the image--if the visible form of a tree is different from that of a house because the tree itself is different from the house, my consciousness is, however remotely, influenced by something different from itself, the _ego_ by the _non-ego_. And on the other hand, if I, who am conscious, am a real being, distinct from the things of which I am conscious--if the conscious mind has a constitution and laws of its own by which it acts, and if the mode of its consciousness is in any degree determined by those laws, the _non-ego_ is so far conditioned by the _ego_; the thing which I see is not seen absolutely and _per se_, but in a form partly dependent upon the laws of my vision.