The definition of the material is not this

I've heard a number of people on the net, typically those with a scientific background, assert that something is material or physical if it can affect anything else. Or, in other words, if it has causal powers.

This is of course a ridiculous definition. It rules out interactive dualism by definition. If the soul or self can move the body, they assert it is material. That's despite the fact the self/soul might not have any location, isn't made out of atoms or anything else, and indeed doesn't have any physical properties whatsoever.

But it gets even worse. Consider Berkeley's metaphysic (subjective idealism). In his metaphysic the only things that have causal powers are finite spirits (i.e us), and the infinite spirit (God). The "external" world of trees, rocks, and stars, are equated with our sensory perceptions (qualia) and of course this "external world" has no causal powers at all. It is God that does everything.

But this then means that spirits -- whether finite or infinite -- are material, but that what we call the physical world is non-material!

Needless to say this is ludicrous. It might be helpful if these people with a scientific background actually thought a little about this.