10. Our different conceptions of the infinity of number contrasted with those of duration and expansion.
It will,
perhaps, give us a little further light into the idea we have of infinity, and discover to us, that it is nothing but the
infinity of number applied to determinate parts, of which we have in our minds the distinct ideas, if we consider
that number is not generally thought by us infinite, whereas duration and extension are apt to be so; which arises
from hence,--that in number we are at one end, as it were: for there being in number nothing less than an unit, we
there stop, and are at an end; but in addition, or increase of number, we can set no bounds: and so it is like a line,
whereof one end terminating with us, the other is extended still forwards, beyond all that we can conceive. But in
space and duration it is otherwise. For in duration we consider it as if this line of number were extended both
ways--to an unconceivable, undeterminate, and infinite length; which is evident to any one that will but reflect on
what consideration he hath of Eternity; which, I suppose, will find to be nothing else but the turning this infinity
of number both ways, à parte ante, and à parte post, as they speak. For, when we would consider eternity, à parte
ante, what do we but, beginning from ourselves and the present time we are in, repeat in our minds the ideas of
years, or ages, or any other assignable portion of duration past, with a prospect of proceeding in such addition
with all the infinity of number: and when we would consider eternity, à parte post, we just after the same rate
begin from ourselves, and reckon by multiplied periods yet to come, still extending that line of number as before.
And these two being put together, are that infinite duration we call Eternity: which, as we turn our view either
way, forwards or backwards, appears infinite, because we still turn that way the infinite end of number, i.e., the
power still of adding more.
