How can physical powers form a secondary kind of qualities? If they
be qualities only so far as they are powers, this definition would
not suit all qualities, as has been said above. If boxing ability be
a quality as far as it is a disposition, it is useless to attribute
to it a power, since power is implied in habituation. Further, how
should we distinguish the natural boxing ability from that which is
scientifically acquired? If both be qualities, they do not imply any
difference so far as one is natural, and the other acquired; that is
merely an accident, since the capacity of boxing is the same form in
both cases.