Habe den Mut, dich deines eigenen Verstandes zu bedienen. - Immanuel Kant

As the analysis of a substantial composite terminates only in a part which is not a whole, that is, in a simple part, so synthesis terminates only in a whole which is not a part, that is, the world.

Space is employed as the type even of the concept of time itself, representing it by a line, and its limits — moments — by points. Time, on the other had, approaches more to a universal and rational concept, comprising under its relations all things whatsoever, to wit, space itself, and besides, those accidents which are not comprehended in the relations of space, such as the thoughts of the soul. Again, time, besides this, though it certainly does not dictate the laws of reason, yet constitutes the principal conditions tinder favor of which the mind compares its notions according to the laws of reason. Thus, I cannot judge what is impossible except by predicating a and not-a of the same subject at the same time.

I ought never to act except in such a way that I could also will that my maxim should become a universal law.