William H. Stoddard: The trouble with this sort of argument, though, is that it treats the legal term “animal” as synonymous with the biological term “animal.”

Well, I stipulated that I was considering the term as “used in contemporary English,” by which I mean ordinary English rather than a particular technical argot. If I were a wagering man, I’d wager that in most ordinary contexts of use “animal” is a deferential term in which non-specialists defer to biologists (not lawyers) for the referent-fixing criteria.

William H. Stoddard: Though whether Superman is nonhuman seems debatable. There’s lots of material from DC that suggests that he and human women are interfertile.

But I don’t think that being interfertile with human beings would make Superman human, or a member of the biological species H. sapiens. Species are constituted (among other things) by their common evolutionary heritage, which Superman — who has an unrelated alien lineage — does not share. (You can hybridize peaches, plums, and apricots; but that doesn’t make them all members of the same species.)

Roderick: If Superman doesn’t count as an animal because he’s not biologically related to homo sapiens, then perhaps Lois Lane doesn’t either, because homo sapiens is the name for a species in our universe whereas Lois Lane lives in the DC universe and is not biologically related to anybody in our universe.

Well, if homo sapiens names a natural kind, surely it names the same natural kind in every possible world, and in a given possible world W it is only the case that humans in W have to be related to all the other humans in W, not that they have to be related (how?) to humans in other worlds not actual relative to W. In order to prove that there are at least some humans in the D.C. universe, you just need to find at least one actual human who exists in the D.C. universe as well as in @. Any such must also be human in the D.C. universe as well as in @ (since humans have humanity essentially, not accidentally). There are in fact plenty of cases of transworld identity (e.g. Franklin D. Roosevelt and Adolf Hitler have both appeared). So as long as it’s part of the story that Lois Lane et al. are appropriately related, evolutionarily speaking, to these known humans, Lois Lane et al. will also count as members of the human species.

Black Bloke: Nivens ignored a lot of things for the sake of comedy.

Too bad, I guess, since the essay is not very funny.