Qualities, therefore, are everything that, instead of being
actualizations and forms of beings, are only its accidents, and only
reveal its shapes. We will therefore call qualities the habituations
and the dispositions which are not essential to substances. The
archetypes (or models) of qualities are the actualizations of the
beings, which are the principles of these qualities. It is impossible
for the same thing at one time to be, and at another not to be a
quality. What can be separated from being is quality; what remains
united to being is being, form, and actualization. In fact, nothing can
be the same in itself, and in some other condition where it has ceased
to be form and an actualization. What, instead of being the form of a
being, is always its accident, is purely and exclusively a quality.