On Sense And The Sensible   

sense-perception. On this supposition, every perceptible object should

be regarded as composed not of perceptible [but of imperceptible]

parts. Yet it must [be really composed of perceptible parts], since

assuredly it does not consist of mathematical [and therefore purely

abstract and non-sensible] quantities. Again, by what faculty should

we discern and cognize these [hypothetical real things without

sensible qualities]? Is it by Reason? But they are not objects of

Reason; nor does reason apprehend objects in space, except when it

acts in conjunction with sense-perception. At the same time, if this

be the case [that there are magnitudes, physically real, but without

sensible quality], it seems to tell in favour of the atomistic

hypothesis; for thus, indeed, [by accepting this hypothesis], the

question [with which this chapter begins] might be solved

[negatively]. But it is impossible [to accept this hypothesis]. Our

views on the subject of atoms are to be found in our treatise on

Movement.

The solution of these questions will bring with it also the answer

to the question why the species of Colour, Taste, Sound, and other

sensible qualities are limited. For in all classes of things lying

between extremes the intermediates must be limited. But contraries are

extremes, and every object of sense-perception involves contrariety:

e.g. in Colour, White x Black; in Savour, Sweet x Bitter, and in all

the other sensibles also the contraries are extremes. Now, that

which is continuous is divisible into an infinite number of unequal

parts, but into a finite number of equal parts, while that which is

not per se continuous is divisible into species which are finite in

number. Since then, the several sensible qualities of things are to be

reckoned as species, while continuity always subsists in these, we

must take account of the difference between the Potential and the

Actual. It is owing to this difference that we do not [actually] see

its ten-thousandth part in a grain of millet, although sight has

embraced the whole grain within its scope; and it is owing to this,