I thought the original question was postulating something like organized
neutrino-like matter -- material and present, but barely interacting
with us.  I don't think this would raise fundamental philosophical
questions, but it would still be damn important.
Merry part,
 -xx- Damien R. Sullivan X-) <*> http://www.ugcs.caltech.edu/~phoenix
For no cage was ever made to hold a creature such as he,
No chain was ever forged to bind the wind.
And when I think upon all the scars he left on me,
The cruelest are the ones I bear within.