and positive idea of infinity.  In which case, let this line be ten, or ten thousand fathoms long, it equally discovers what is beyond it, and gives only this confused and comparative idea, that this is not all, but one may yet go farther.  So much as the mind comprehends of any space, it has a positive idea of:  but in endeavouring to make it infinite,—­it being always enlarging, always advancing,—­the idea is still imperfect and incomplete.  So much space as the mind takes a view of in its contemplation of greatness, is a clear picture, and positive in the understanding:  but infinite is still greater. 1.  Then the idea of so much is positive and clear. 2.  The idea of greater is also clear; but it is but a comparative idea, the idea of so much greater as cannot be comprehended. 3.  And this is plainly negative:  not positive.  For he has no positive clear idea of the largeness of any extension, (which is that sought for in the idea of infinite), that has not a comprehensive idea of the dimensions of it:  and such, nobody, I think, pretends to in what is infinite.  For to say a man has a positive clear idea of any quantity, without knowing how great it is, is as reasonable as to say, he has the positive clear idea of the number of the sands on the sea-shore, who knows not how many there be, but only that they are more than twenty.  For just such a perfect and positive idea has he of an infinite space or duration, who says it is larger than the extent or duration of ten, one hundred, one thousand, or any other number of miles, or years, whereof he has or can have a positive idea; which is all the idea, I think, we have of infinite.  So that what lies beyond our positive idea towards infinity, lies in obscurity, and has the indeterminate confusion of a negative idea, wherein I know I neither do nor can comprehend all I would, it being too large for a finite and narrow capacity.  And that cannot but be very far from a positive complete idea, wherein the greatest part of what I would comprehend is left out, under the undeterminate intimation of being still greater.  For to say, that, having in any quantity measured so much, or gone so far, you are not yet at the end, is only to say that that quantity is greater.  So that the negation of an end in any quantity is, in other words, only to say that it is bigger; and a total negation of an end is but carrying this bigger still with you, in all the progressions your thoughts shall make in quantity; and adding this idea of still greater to all the ideas you have, or can be supposed to have, of quantity.  Now, whether such an idea as that be positive, I leave any one to consider.

16.  We have no positive Idea of an infinite Duration.