Our different conception of the infinity of number, duration, and expansion.§ 10. It will, perhaps, give us a little farther 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, he 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.
§ 11. The same happens also in space, wherein conceiving ourselves to be as it were in the centre, we do
