From time to time various writers have told us that we cannot reach any conclusions about the origin or development of the universe, since it is (whether by logic or just in fact) a unique object, the only one of its kind, and rational inquiry can only reach the conclusions about objects which belong to kinds, e.g. it can reach a conclusion about what will happen to this bit of iron, because there are other bits of iron, the behaviour of which can be studied. This objection of course has the surprising, and to most of these writers unwelcome, consequence, that physical cosmology cannot reach justified conclusions about such matters as the size, age, rate of expansion, and density of the universe as a whole (because it is a unique object); and also that physical anthropology cannot reach conclusions about the origin and development of the human race (because, as far as our knowledge goes, it is the only one of its kind). The implausibility of these consequences leads us to doubt the original objection, which is indeed misguided.