 Others have provided interpretations according to which Aristotle does not maintain all of (i)–(iii), and there is a considerable variety of such interpretations, too many to be canvassed here. But there are two main, and opposed, lines of interpretation. According to one, Aristotle’s substantial forms are not universals after all, but each belongs exclusively to the particular whose form it is, and there are therefore as many substantial forms of a given kind as there are particulars of that kind. According to the other, Aristotle’s arguments in Ζ.13 are not intended to show that no universal is a substance, tout court, but some weaker thesis that is compatible with there being only one substantial form for all of the particulars belonging to the same species. Proponents of particular forms (or essences) include Sellars 1957, Harter 1975, Hartman 1977, Irwin 1988, and Witt 1989b. Opponents include Woods 1967, Owen 1978, Code 1986, Loux 1991, and Lewis 1991.