On The Soul
disappear from existence at one and the same moment, and so actual
savour and actual tasting, &c., while as potentialities one of them
may exist without the other. The earlier students of nature were
mistaken in their view that without sight there was no white or black,
without taste no savour. This statement of theirs is partly true,
partly false: 'sense' and 'the sensible object' are ambiguous terms,
i.e. may denote either potentialities or actualities: the statement is
true of the latter, false of the former. This ambiguity they wholly
failed to notice.
If voice always implies a concord, and if the voice and the
hearing of it are in one sense one and the same, and if concord always
implies a ratio, hearing as well as what is heard must be a ratio.
That is why the excess of either the sharp or the flat destroys the
hearing. (So also in the case of savours excess destroys the sense
of taste, and in the case of colours excessive brightness or
darkness destroys the sight, and in the case of smell excess of
strength whether in the direction of sweetness or bitterness is
destructive.) This shows that the sense is a ratio.
That is also why the objects of sense are (1) pleasant when the
sensible extremes such as acid or sweet or salt being pure and unmixed
are brought into the proper ratio; then they are pleasant: and in
general what is blended is more pleasant than the sharp or the flat
alone; or, to touch, that which is capable of being either warmed or
chilled: the sense and the ratio are identical: while (2) in excess
the sensible extremes are painful or destructive.
Each sense then is relative to its particular group of sensible
qualities: it is found in a sense-organ as such and discriminates
the differences which exist within that group; e.g. sight
discriminates white and black, taste sweet and bitter, and so in all
cases. Since we also discriminate white from sweet, and indeed each
sensible quality from every other, with what do we perceive that
they are different? It must be by sense; for what is before us is