Origin Essentialism in Biology

Kripke argues for origin essentialism, the view that the same individual cannot have multiple origins. Sober hypothesises that Kripke's origin essentialism applies to biological species. This paper shows that Sober's hypothesis fails. Because Kripke's original argument is invalid, it cannot vindicate Sober's proposal. Salmon offers an influential reformulation of Kripke's argument but his argument fails to extend to species: the notion of an individual's origin is too narrow to apply to species, and Salmon's argument rests on a thought experiment that conflicts with how species evolve. Thus, Sober and others are wrong to think that Kripke's origin essentialism can save species essentialism.