element of a line in consciousness is divisible or not. Any argument from the possibility of dividing its substitutes evidently has nothing to do with this point. It is plain that this doctrine, which makes any particular finite line in consciousness to consist of a limited number of simple parts, is not open to the objection that it necessitates the absurdity of exhausting an endless series. Moving along such a line, Achilles could overtake the tortoise, for the successively diminishing distances between them do not constitute an endless series. The descending series results after a limited number of terms in the simple, and the series is broken, for the simple does not consist of parts. In this there is at least no contradiction. It remains to see what other objections may lie against it. It may be argued, first, as it often is argued, that it is impossible to conceive of any part of a line as not itself extended and having parts. It may be admitted that the small parts arrived at do not seem to have part out of part; that these sub-parts are not observed in them, but still it is said that one who thinks about them cannot but think of them as really having such parts. I ask one who puts forward this objection to look into his own mind and see whether he does not mean by "thinking about them," bringing them in imagination nearer to the eye, or by some means substituting for them what can be seen to have part out of part. That one can do this no one would think of denying, but, as I have said, this does not prove the original parts to be extended. It may be objected again that extension can never be built up out of the non-extended--that if one element of a given kind has, taken alone, no extension at all, two or more such elements together cannot have any extension either. I answer that a straight line has no angularity at all, and yet two straight lines may obviously make an angle; that one man is not in the least a crowd, but that one hundred men may be; that no single tree is a forest, but that many trees together do make a forest; that a uniform expanse of color is in no sense a variegated surface, but that several such together do make a variegated surface. It may be that extension is simply the name we give to several simple sense-elements of a particular kind taken together. One cannot say off-hand that it is not.