Wikipedia says "Even restricting the discussion to physics, scientists do not have a unique definition of what matter is." (in the sense of contrasting with ant

Wikipedia says "Even restricting the discussion to physics, scientists do not have a unique definition of what matter is." (in the sense of contrasting with antimatter), and then later says "In a wider sense, one can use the word matter simply to refer to fermions.". (Presumably this means, fermions and things comprised of fermions. One would not say that Helium-4 is not matter just because it is a boson (and is comprised of an even number of fermions).) Electrons are fermions. I am therefore comfortable saying that electrons are matter. I don't know why you say that electrons are "not particles" in QFT. Sure, there's an electron field, and electrons are just, like, excitations in that field. There's also a quark field. What of it? If you are saying "because everything is fields, there are therefore no particles, and therefore no matter", you are using the word "matter" in a silly way. Also, isn't a "particle" just a representation of a compact Lie group? What's the problem? (edit : though, I admit that I'd be a little hesitant about calling a massless fermion "matter". But, seeing as there are no known massless fermions, meh.)