On Sense And The Sensible   

too, that the sound contained in a quarter-tone escapes notice, and

yet one hears the whole strain, inasmuch as it is a continuum; but the

interval between the extreme sounds [that bound the quarter-tone]

escapes the ear [being only potentially audible, not actually]. So, in

the case of other objects of sense, extremely small constituents are

unnoticed; because they are only potentially not actually [perceptible

e.g.] visible, unless when they have been parted from the wholes. So

the footlength too exists potentially in the two-foot length, but

actually only when it has been separated from the whole. But objective

increments so small as those above might well, if separated from their

totals, [instead of achieving 'actual' exisistence] be dissolved in

their environments, like a drop of sapid moisture poured out into

the sea. But even if this were not so [sc. with the objective

magnitude], still, since the [subjective] of sense-perception is not

perceptible in itself, nor capable of separate existence (since it

exists only potentially in the more distinctly perceivable whole of

sense-perception), so neither will it be possible to perceive

[actually] its correlatively small object [sc. its quantum of

pathema or sensible quality] when separated from the object-total. But

yet this [small object] is to be considered as perceptible: for it

is both potentially so already [i.e. even when alone], and destined to

be actually so when it has become part of an aggregate. Thus,

therefore, we have shown that some magnitudes and their sensible

qualities escape notice, and the reason why they do so, as well as the

manner in which they are still perceptible or not perceptible in

such cases. Accordingly then when these [minutely subdivided]

sensibles have once again become aggregated in a whole in such a

manner, relatively to one another, as to be perceptible actually,

and not merely because they are in the whole, but even apart from

it, it follows necessarily [from what has been already stated] that

their sensible qualities, whether colours or tastes or sounds, are

limited in number.