[yters]

That makes the term 'physical' vacuous.

Technically, we already recognize the world is non-physical. Materialists defined materialism to things bumping into each other. Now we know there are things like field effects, attraction, and action at a distance. So there is a non-bumping substrate that the bumping things exist within. Thus, strict physicalism is already known to be false.

[adrianN]

No it doesn't. It just implies that everything that causally interacts with the observable reality is physical. It leaves open the door for an immortal soul, it's just that the existence or nonexistence of the soul has absolutely no effect on the observable universe.

The term physicalism was introduced a few decades after we figured out Maxwell's equations. If the philosophers defined it to mean things bumping into other things they were frankly poorly informed about the world we live in.

[yters]

What if the immortal soul causally interacts with the observable reality? You cannot define away that possibility.

[adrianN]

If it's a proper interaction and not just a one-way influence from reality->soul, then the soul subject to the study of physics.

[yters]

Sure, but that doesn't imply the soul is physical. I am interacting with you through HTTP, but that doesn't make me or you HTTP.