PROP. VI.————
instead of any other. Hence this element is contingent throughout all its phases. On the other hand, the universal element is regarded as necessary, not because it alone is essential to the constitution of knowledge, but because it is invariable. On this factor no changes can be rung. Being the common quality of all knowledge, it admits of no variation; being the same in all, it can have no substitute; being uniform, it has no phases. It can never be other than it is. If it could, it would no longer be the common quality. Our cognitions would lose their unity. They would cease to be cognitions, just as they would cease to be cognition by the suppression of the peculiar element which imparts to them their diversity. Hence the common element is necessary with a double necessity. It can neither be abolished nor changed. The particular element is necessary only with a single necessity. It cannot be abolished: some peculiarity must attach to every cognition; but it can be changed; it is changed incessantly. Vicissitude is its very character; and therefore, in all its forms, it is contingent or accidental.
Why this proposition is introduced.3. The truth of this proposition was tacitly assumed in the introduction to this work, and is indeed presupposed by the very nature and terms of the inquiry. For when it is asked, What is the one element common to all knowledge—the constant