Immanuel Kant's Critique of Pure Reason — trans. F. Max Müller

We have declared ourselves from the very beginning in favour of this transcendental idealism. In our system, therefore, we need not .hesitate to admit the existence of matter on the testimony of mere self-consciousness, and to consider it as established by it (sc. the testimony), in the same manner as the existence of myself, as a thinking being. I am conscious of my representations, and hence they exist as well as I myself, who has these representations. External objects, however (bodies), are phenomena only, therefore nothing but a class of my representations, the objects of which are something by means of these representations only, and apart from them nothing, [p. 371] External things, therefore, exist by the same right as I myself, both on the immediate testimony of my self-consciousness, with this difference only, that the representation of myself, as a thinking subject, is referred to the internal sense only, while the representations which indicate extended beings are referred to the external sense also. With reference to the reality of external objects, I need as little trust to inference, as with reference to the reality of the object of my internal sense (my thoughts), both being nothing but representations, the immediate perception (consciousness) of which is at the same time a sufficient proof of their reality.

The transcendental idealist is, therefore, an empirical realist, and allows to matter, as a phenomenon, a reality which need not be inferred, but may be immediately perceived. The transcendental realism, on the contrary, is necessarily left in doubt, and obliged to give way to

302 Transcendental Dialectic 3empirical idealism, because it considers the objects of the external senses as something different from the senses themselves, taking mere phenomena as independent beings, existing outside us. And while with the very best consciousness of our representation of these things, it is far from certain that, if a representation exists, its corresponding object must exist also, it is clear that in our system external things, that is, matter in all its shapes and changes, are nothing but mere phenomena, [p. 372] that is, representations within us, of the reality of which we are immediately conscious.

As, so far as I know, all psychologists who believe in empirical idealism are transcendental realists, they have acted no doubt quite consistently, in ascribing great importance to empirical idealism, as one of the problems from which human reason could hardly extricate itself. For indeed, if we consider external phenomena as representations produced inside us by their objects, as existing as things by themselves outside us, it is difficult to see how their existence could be known otherwise but through a syllogism from effect to cause, where it must always remain doubtful, whether the cause be within or without us. Now we may well admit that something which, taken transcendentally, is outside us, may be the cause of our external intuitions, but this can never be the object which we mean by the representations of matter and material things ; for these are phenomena only, that is, certain kinds of representations existing always within us, and the reality of which depends on our immediate consciousness, quite as much as the consciousness of my own thoughts. The transcendental object is unknown equally in regard to internal and external intuition.