On Generation and corruption   

distance. For the fire heats the air, and the air-being by nature such

as both to act and suffer action-heats the body.) But the

supposition that a body is 'susceptible in some parts, but

insusceptible in others' (is only possible for those who hold an

erroneous view concerning the divisibility of magnitudes. For us)

the following account results from the distinctions we established

at the beginning. For (i) if magnitudes are not divisible through

and through-if, on the contrary, there are indivisible solids or

planes-then indeed no body would be susceptible through and through

:but neither would any be continuous. Since, however, (ii) this is

false, i.e. since every body is divisible, there is no difference

between 'having been divided into parts which remain in contact' and

'being divisible'. For if a body 'can be separated at the contacts'

(as some thinkers express it), then, even though it has not yet been

divided, it will be in a state of dividedness-since, as it can be

divided, nothing inconceivable results. And (iii) the suposition is

open to this general objection-it is a paradox that 'passion' should

occur in this manner only, viz. by the bodies being split. For this

theory abolishes 'alteration': but we see the same body liquid at

one time and solid at another, without losing its continuity. It has

suffered this change not by 'division' and composition', nor yet by

'turning' and 'intercontact' as Democritus asserts; for it has

passed from the liquid to the solid state without any change of

'grouping' or 'position' in the constituents of its substance. Nor are

there contained within it those 'hard' (i.e. congealed) particles

'indivisible in their bulk': on the contrary, it is liquid-and

again, solid and congealed-uniformly all through. This theory, it must

be added, makes growth and diminution impossible also. For if there is

to be opposition (instead of the growing thing having changed as a

whole, either by the admixture of something or by its own

transformation), increase of size will not have resulted in any and

every part.