"Even Flow, thoughts arrive like butterflies..."

I love Pearl Jam. Anyone who knows me is aware of that. And I would have to say that "Even Flow" is still my favourite Pearl Jam song (heck, it's in my top five of all time) and thus I feel like an idiot for asking this, but my question is this: WHY IS IT CALLED EVEN FLOW??? I know that the song is about an homeless man, but is that the man's name? I mean, it's a cool-sounding song title but I don't understand its significance. If anyone could enlighten me or give me some thoughts, I would appreciate it greatly. Cheers...