PROP. VI.————
Explanation of words."necessary" (or essential), "universal" (or common or general), as here employed, are nearly or altogether synonymous. The unchangeable is that which cannot be changed in cognition, and is therefore equivalent to the necessary and universal. The necessary is that which cannot be dispensed with, or got rid of in cognition, and is therefore equivalent to the unchangeable and universal. The universal is that which is everywhere and always present in cognition, and is therefore equivalent to the unchangeable and necessary. In contrast to these terms stand the words "changeable" (or fluctuating), contingent" (or accidental), "particular" (or peculiar). These, too, are mere varieties of the same expression. The changeable is that which can be changed in cognition, and is therefore equivalent to the contingent and particular. The contingent is that which may be otherwise in cognition, and is therefore equivalent to the changeable and particular. The particular is that which may be displaced in cognition, and replaced by some other particular, and is therefore equivalent to the changeable and contingent
In what sense the contingent element is necessary, and in what sense it is contingent.2. This proposition declares that every cognition must contain a particular and contingent, as well as a universal and necessary element. Hence it may be concluded that the contingent element is as necessary to the constitution of knowledge as the