[fabfoe]

It’s actually the Jevons paradox, non possessive, named for William Stanley Jevons. I thought it was possessive too because many people write it that way.

[hombre_fatal]

I don't see why it can't be written possessively since he stipulated it. It makes more sense.

You would write it Jevons' paradox. Six sources on its wiki page write it as such in their title.