Further, in the case of things in which the distinction of prior and posterior is present, that which is predicable of these things cannot be something apart from them; eg if two is the first of numbers, there will not be a number apart from the kinds of numbers; and similarly there will not be a figure apart from the kinds of figures; and if the genera of these things do not exist apart from the species, the genera of other things will scarcely do so; for genera of these things are thought to exist if any do.