I think thought would be best defined as the change in the organization of
matter and energy over time. Although this statement needs some more
qualifiers; it allows to many things to be considered thought. Probably a
requirement that the organization moves in the opposite direction of
entropy (at least on the average) would probably be a good idea. This is
still to open, but getting closer. Does anyone else have any refinements
that might help? Or possibly this definition could stay almost as broad,
and be allowed to consider the possibility of thought by "non-living"
systems. e.x. The organization of the universe following the big bang
into planets, solar systems, clusters, galaxies, etc.