 However, since the common nature is not a species in its absolute consideration, but only insofar as it is in the mind, the conclusion does not follow. Indeed, this reasoning would be just as invalid as the one trying to prove that this book, pointing to the second edition which is actually 100 pages, is 200 pages, because the same book was 200 hundred pages in its first edition. For just as its being 200 pages belongs to the same book only in its first edition, so its being a species belongs to human nature only as it exists in the mind.