The first principles, therefore, are existence and intelligence,
identity and difference, movement and rest.[230] Rest is the condition
of identity; movement is the condition of thought, since the latter
presupposes the differences of the thinking subject and of the object
thought, and because it is silent if reduced to unity. The elements
of thought (subject and object) must thus stand in the relation
of differences, but also in that of unity, because they form a
consubstantial unity, and because there is a common element in all that
is derived therefrom. Besides, here difference is nothing else than
distinction. The plurality formed by elements of thought constitutes
quantity and number;[231] and the characteristic of every element,
quality.[232] From these first principles (the categories, that are the
genera of being) all things are derived.