If Canada’s not real, are Canadians real? Asking for the sake of my own existence

I'm thinking in particular of this footnote in Kant's Idea for a Universal History:

If you become a Thomist, you'll have to deal with something comparably annoying: sedevacantism and the SSPX.

Sadly I'll only be there for the Sunday, and there are other talks that I think I need to go to - but I hope your panels all go well!

That's a good point. I think I struggle with this idea in history of philosophy classes - it's easy to imagine cutting some material, and receiving the response, 'you didn't assign such-and-such crucial passage? Utter heresy!'

I suspect one reason is that a concern with what reading is and ought to be looks to a lot of philosophers like something belonging to the continental tradition, so it gets passively sorted away with Derrida and psychoanalysis

I know someone who thinks that the first non-Medieval philosopher was Kant