A quality is therefore a power which adds (essential) characteristics
to already existing beings. These characteristics which differentiate
beings can therefore be called qualities only figuratively. Qualities
are, rather, actualizations and reasons, or parts of reasons, which
proclaim the "whatness," though the latter seem to qualify being.
As to the qualities which really deserve this name, which "qualify"
things, which we generally call "potentialities," they are the
reasons and shapes, either of the soul or the body, such as beauty or
ugliness.[264]