[split] t-shirt to soul topic

[Tiberius]

I'm the one claiming that something doesn't exist physically = I am the one making the negative claim

"in most cases the burden of proof rests on those who claim something exists"

Actually, the burden of proof rests on the one making any claim. You are not claiming that thought doesn't exist physically, you are claiming that thought exists non-physically.

Physical existence is the default position given it is the observable and testable position. To say something exists but non-physically is to make the positive claim, since non-physical things are not observable / testable.