This caught my eye, too.
By "ultimate grounds" I think CarrotTop meant "definitive ones" (or "final", that everybody agrees upon - if only as, say, a "basis").
But we'll see his/her reply... ;)
(Christian here. Just lurking on atheists' thoughts once in a while. 'Hope they don't mind. :)
"Cyril" pronounced "see real". I code stuff.
"To study and not think is a waste. To think and not study is dangerous." -- Confucius