even of himself only by the inner sense, and consequently only through the appearances of his nature and the way in which his consciousness is affected.  At the same time beyond these characteristics of his own subject, made up of mere appearances, he must necessarily suppose something else as their basis, namely, his ego, whatever its characteristics in itself may be.  Thus in respect to mere perception and receptivity of sensations he must reckon himself as belonging to the world of sense, but in respect of whatever there may be of pure activity in him (that which reaches consciousness immediately and not through affecting the senses) he must reckon himself as belonging to the intellectual world, of which, however, he has no further knowledge.  To such a conclusion the reflecting man must come with respect ito all the things which can be presented to him:  it is probably to be met with even in persons of the commonest understanding, who, as is well known, are very much inclined to suppose behind the objects of the senses something else invisible and acting of itself.  They spoil it, however, by presently sensualizing this invisible again; that is to say, wanting to make it an object of intuition, so that they do not become a whit the wiser.

Now man really finds in himself a faculty by which he distinguishes himself from everything else, even from himself as affected by objects, and that is Reason.  This being pure spontaneity is even elevated above the understanding.  For although the latter is a spontaneity and does not, like sense, merely contain intuitions that arise when we are affected by things (and are therefore passive), yet it cannot produce from its activity any other conceptions than those which merely serve to bring the intuitions of sense under rulesf and thereby to unite them in one consciousness, and without this use of the sensibility it could not think at all; whereas, on the contrary, Reason shows so pure a spontaneity in the case of what I call Ideas [Ideal Conceptions] that it thereby far transcends everything that the sensibility can give it, and exhibits its most important function in distinguishing the world of sense from that of understanding, and thereby prescribing the limits of the understanding itself.

For this reason a rational being must regard himself qua intelligence (not from the side of his lower faculties) as belonging not to the world of sense, but to that of understanding; hence he has two points of view from which he can regard himself, and recognise laws of the exercise of his faculties, and consequently of all his actions:  first, so far as he belongs to the world of sense, he finds himself subject to laws of nature (heteronomy); secondly, as belonging to the intelligible world, under laws which being independent on nature have their foundation not in experience but in reason alone.