like the brain is literally encased in the body so how can it be separate? like if you go around licking lamp posts you’re going to pick up some germ that’s gonna make you feel like crap and you get insomnia or fever and your brain will definitely be impacted. and so you’ll have short temper and that’ll get you into trouble.
True, and nondual traditions like tantric Buddhism, Advaita Vedanta, and Kashmir Shivism really have a leg up in that regard, but Descartes really cemented it as the supposed “objective” fact (lol) that it is today.
The root problem though is the felt sense of separation the mind creates but that mystical experiences can dissolve.