Matter is a very poor choice of words. Energy is not matter and it is visible in in daily life. Space exists but it is not matter. It is basically the absence of matter. Scientists believe several particles which are not technically "matter" in neutrinos, tachyons, gravitons. Is Dark Matter, matter? Certainly "Dark energy" is not.

That is the American Atheist definition used to argue the position of that organization to the Supreme Court of the United States. IMHO the word "matter" is confusing and should be deleted.

It is probable that that definition was written by a layperson, not a scientist, Possibly a lawyer.


http://atheists.org/atheism