By whether or not you feel. :-)
This is very interesting, and in fact is something that is not only in research as we "speak," but this very communication is a component or facet or aspect, if you will, of that research. Otherwise, I just rely on my felt-sense. Most people have their felt-sense shut down, and that's the affliction that gives rise to ULs like "you're only using 10% of your brain." Pfaugh! You might be using 100% of your _brain_, but you haven't even _ACKNOWLEDGED THE EXISTENCE_ of your
---- ---- Whoops! I almost had a "Norman: Coordinate" there! %-\
- Does it matter?
This is also a very cool question. I'm going to have some more drugs now.