ROFL.... I fergit if it was Azimov or Arthur C. Clark, but it's an amazing quote: "
Technology, sufficiently advanced, is indistinguishable from magic."
We don't think about the current our houses are attached to, the enormous infrastructure that makes it all possible (until some yahoo hits a pole and brings it all crashing down, anyway), we just flip a switch... MAGIC! We have light/sound/whatever we want, at the touch of a button or toggle-switch. Something you can't see or otherwise perceive is very much like a magical force -- it's certainly not tactile, because touching electricity is a REALLY bad idea...
So it's a theoretical measurement of a non-tactile force. Far more than THIS brain can deal with.
Andria