On Generation and corruption   

exhibits this character. But at present we are to state the material

cause-the cause classed under the head of matter-to which it is due

that passing-away and coming-to-be never fail to occur in Nature.

For perhaps, if we succeed in clearing up this question, it will

simultaneously become clear what account we ought to give of that

which perplexed us just now, i.e. of unqualified passingaway and

coming-to-be.

Our new question too-viz. 'what is the cause of the unbroken

continuity of coming-to-be?'-is sufficiently perplexing, if in fact

what passes-away vanishes into 'what is not' and 'what is not' is

nothing (since 'what is not' is neither a thing, nor possessed of a

quality or quantity, nor in any place). If, then, some one of the

things 'which are' constantly disappearing, why has not the whole of

'what is' been used up long ago and vanished away assuming of course

that the material of all the several comings-to-be was finite? For,

presumably, the unfailing continuity of coming-to-be cannot be

attributed to the infinity of the material. That is impossible, for

nothing is actually infinite. A thing is infinite only potentially,

i.e. the dividing of it can continue indefinitely: so that we should

have to suppose there is only one kind of coming-to-be in the

world-viz. one which never fails, because it is such that what

comes-to-be is on each successive occasion smaller than before. But in

fact this is not what we see occurring.

Why, then, is this form of change necessarily ceaseless? Is it

because the passing-away of this is a coming-to-be of something

else, and the coming-to-be of this a passing-away of something else?

The cause implied in this solution must no doubt be considered

adequate to account for coming-to-be and passing-away in their general

character as they occur in all existing things alike. Yet, if the same

process is a coming to-be of this but a passing-away of that, and a

passing-away of this but a coming-to-be of that, why are some things

said to come-to-be and pass-away without qualification, but others