Again, if the causes of substances are causes of everything, still different things have different causes and elements, as was said; the causes of things that are not in the same class, eg of colours, sounds, substances, and quantities, are different except in an analogical sense; and those of things in the same species are different, not in species, but in the sense that the causes of different individuals are different, your matter and form and moving cause being different from mine, while in their universal formula they are the same.