On the Fourfold Root of the Principle of Sufficient...

Space and Time are so constituted, that all their parts stand in mutual relation, so that each of them conditions and is conditioned by another. We call this relation in Space, position; in Time, succession. These relations are peculiar ones, differing entirely from all other possible relations of our representations; neither the Understanding nor the Reason are therefore able to grasp them by means of mere conceptions, and pure intuition à priori alone makes them intelligible to us; for it is impossible by mere conceptions to explain clearly what is meant by above and below, right and left, behind and before, before and after. Kant rightly confirms this by the assertion, that the distinction between our right and left glove cannot be made intelligible in any other way than by intuition. Now, the law by which the divisions of Space and of Time determine one another reciprocally with reference to these relations (position and succession) is what I call the Principle of the Sufficient Reason of Being, principium rationis sufficientis essendi. I have already given an example of this relation in § 15, by which I have shown, through the connection between the sides and angles of a triangle, that this relation is not only quite different from that between cause and effect, but also from that between reason of knowledge and consequent; wherefore here the condition may be called Reason of Being, ratio essendi.

The insight into such a reason of being can, of course, become a reason of knowing: just as the insight into the law of causality and its application to a particular case is the reason of knowledge of the effect; but this in no way annuls the complete distinction between Reason of Being, Reason of Becoming, and Reason of Knowing. It often happens, that what according to one form of our principle is consequence, is, according to another, reason. The rising of the quicksilver in a thermometer, for instance, is the consequence of increased heat according to the law of causality, while according to the principle of the sufficient reason of knowing it is the reason, the ground of knowledge, of the increased heat and also of the judgment by which this is asserted.