Thou dost well to refrain from contesting my existence on the ground that it is linked to individuals; for, as inseparably as I am joined to them, thou art joined to thy sister, Form, and hast never appeared without her. No eye hath yet seen either thee or me naked and isolated; for we are both mere abstractions. It is in reality _one_ being that perceives itself and is perceived by itself, but whose real being cannot consist either in perceiving or in being perceived, since these are divided between us two. _Both._ We are, then, inseparably joined together as necessary parts of one whole, which includes us both and exists through us. Only a misunderstanding can oppose us two hostilely to each other, and hence draw the false conclusion that the one contests the existence of the other, with which its own existence stands or falls. ‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ This whole, which comprehends both, is the world as idea, or the world of phenomena. When this is taken away there remains only what is purely metaphysical, the thing in itself, which in the second book we shall recognise as the will. Chapter II. The Doctrine of Perception or Knowledge Of The Understanding. With all _transcendental_ ideality the objective world retains _empirical_ reality; the object is indeed not the thing in itself, but as an empirical object it is real. It is true that space is only in my head; but empirically my head is in space. The law of causality can certainly never enable us to get quit of idealism by building a bridge between things in themselves and our knowledge of them, and thus certifying the absolute reality of the world, which exhibits itself in consequence of its application; but this by no means does away with the causal relation of objects to each other, thus it does not abolish the causal relation which unquestionably exists between the body of each knowing person and all other material objects. But the law of causality binds together only phenomena, and does not lead beyond them. With that law we are and remain in the world of objects, _i.e._, the world of phenomena, or more properly the world of ideas. Yet the whole of such a world of experience is primarily conditioned by the knowledge of a subject in general as its necessary presupposition, and then by the special forms of our perception and apprehension, thus necessarily belongs to the merely _phenomenal_, and has no claim to pass for the world of things in themselves. Indeed the subject itself (so far as it is merely the _knowing_ subject) belongs to the merely phenomenal, of which it constitutes the complementary half.