The highest species concept may be that of a terrestrial rational being; however, we shall not be able to name its character because we have no knowledge of non-terrestrial rational beings that would enable us to indicate their characteristic property and so to characterize this terrestrial being among rational beings in general. It seems, therefore, that the problem of indicating the character of the human species is absolutely insoluble, because the solution would have to be made through experience by means of the comparison of two species of rational being, but experience does not offer us this. (Kant: Anthropology from a Pragmatic Point of View, 225)

Are there alien philosophers orbiting some faraway star, opining in bursts of symbolically articulated smells, or parsing distinctions-without-differences via the clasp of neural genitalia? What would an alien philosophy look like? Do we have any reason to think we might find some…