Beth, my outsider's understanding was that "dualism" was a philosophical camp or umbrella used to describe a particular philosophical camp. which mostly fell out of favor. So calling someone a duelist in philosophical circles was a way of dismissing them as misguided. And non-dualist was the negation of that camp. e. g. the rejection of a separate spirtual plane, etc. But this monkier was really owned by materialists, reductionists, etc. who were mostly trying to distance themselves entirely from spiritual interpretations of things.

the way you are using the term seems different than my understanding of how Philosophers typically use the term.

am I off base here?

--dan