Using the Merriam-Webster definition, you'll find something that meshes well with Eric's stated position.
1: a person who holds the view that any ultimate reality (as God) is unknown and probably unknowable; broadly : one who is not committed to believing in either the existence or the nonexistence of God or a god
Notice the second part, the broader definition. Using that definition (which I think a reading of Eric's post supports) you can, I think, see where he gets his three broad brush positions. Problem seems to be that from his grouping of Atheist, you get two different species. The philosophical atheist and the faith based atheist. The philosophical atheist overlaps position-wise with the agnostic and the faith based atheist, and I'm not sure it really deserves its own category. Problem is, there is no compelling reason to lump it with one side or the other. (So yeah, I'm wrong, we need 4 legs. Actually we need a fifth leg for the folks who aren't theists but who believe in the supernatural (and not just the unexplained natural) and probably a sixth grouping for folks who believe in some sort of theistic entities who work within the rules, naturalistic deities (I'd say arguably the later Norse, Greek, and Roman gods probably would fit there, and there are at least some Oden and Thor followers knocking about.)
Re: a late arrival
1: a person who holds the view that any ultimate reality (as God) is unknown and probably unknowable; broadly : one who is not committed to believing in either the existence or the nonexistence of God or a god
Notice the second part, the broader definition. Using that definition (which I think a reading of Eric's post supports) you can, I think, see where he gets his three broad brush positions. Problem seems to be that from his grouping of Atheist, you get two different species. The philosophical atheist and the faith based atheist. The philosophical atheist overlaps position-wise with the agnostic and the faith based atheist, and I'm not sure it really deserves its own category. Problem is, there is no compelling reason to lump it with one side or the other. (So yeah, I'm wrong, we need 4 legs. Actually we need a fifth leg for the folks who aren't theists but who believe in the supernatural (and not just the unexplained natural) and probably a sixth grouping for folks who believe in some sort of theistic entities who work within the rules, naturalistic deities (I'd say arguably the later Norse, Greek, and Roman gods probably would fit there, and there are at least some Oden and Thor followers knocking about.)