From early times — in Plato's system the thought is already foreshadowed, if not expressed — the shadowy realm of concepts and the world of reality have been counterposed to one another as timeless being and temporal being. This introduces a determination of such universal and profound significance that it is neither possible nor necessary to alter or improve it. No one disputes that whatever is real for us is in time, and that concepts are timeless. Here we may rely on the consensus omnium and go on to the next step without fear of contradiction. On this point, no explicit justification or demonstration is required, only elucidation and clarification.