On Sense And The Sensible   

why, to persons at a distance from the juxtaposed blacks and whites,

some one colour should not appear to present itself as a blend of

both. [But it would not be so on a nearer view], for it will be shown,

in a discussion to be undertaken later on, that there is no

magnitude absolutely invisible.

(3) There is a mixture of bodies, however, not merely such as some

suppose, i.e. by juxtaposition of their minimal parts, which, owing to

[the weakness of our] sense, are imperceptible by us, but a mixture by

which they [i.e. the 'matter' of which they consist] are wholly

blent together by interpenetration, as we have described it in the

treatise on Mixture, where we dealt with this subject generally in its

most comprehensive aspect. For, on the supposition we are criticizing,

the only totals capable of being mixed are those which are divisible

into minimal parts, [e.g. genera into individuals] as men, horses,

or the [various kinds of] seeds. For of mankind as a whole the

individual man is such a least part; of horses [as an aggregate] the

individual horse. Hence by the juxtaposition of these we obtain a

mixed total, consisting [like a troop of cavalry] of both together;

but we do not say that by such a process any individual man has been

mixed with any individual horse. Not in this way, but by complete

interpenetration [of their matter], must we conceive those things to

be mixed which are not divisible into minima; and it is in the case of

these that natural mixture exhibits itself in its most perfect form.

We have explained already in our discourse 'On Mixture' how such

mixture is possible. This being the true nature of mixture, it is

plain that when bodies are mixed their colours also are necessarily

mixed at the same time; and [it is no less plain] that this is the

real cause determining the existence of a plurality of colours- not

superposition or juxtaposition. For when bodies are thus mixed,

their resultant colour presents itself as one and the same at all

distances alike; not varying as it is seen nearer or farther away.

Colours will thus, too [as well as on the former hypotheses], be