To be honest, I had difficulty writing my previous post because I do think a more detailed definition of "structural limits" is required.  Given that I've expressed my belief that all things necessarily share a fundamental characteristic of identity -- and that observable differences must arise out of similarity -- I could have just gone ahead and jumped down the rabbit hole as far as I possibly could and asserted that something moving at the farthest reaches of observable space must be the direct result of mental processes since the two must share a common identity and to that extent are the same (i.e. if mental processes occurring 'here' share a fundamental identity with physical phenomena occurring 'there', then changes in mental process 'here' must directly effect changes in physical phenomena 'there').  However, I wanted to leave the "differences" still in tact, for practical reasons.  Someone like Rassah would claim that just asserting that everything is fundamentally the same and thus everything directly effects everything doesn't lend itself to much practical utility, and generally I would agree.  I was trying to stay consistent within a particular context.

But, with specific regards to your post, and staying within the context I've chosen, I'm not sure everyone would agree that saying the "brain" produces a magnetic field affecting physical phenomena beyond the body is the same as saying "mental processes" produce a magnetic field affecting physical phenomena.