I think he's quoting a scientific philosophical conundrum which is that life is a PROCESS not a actual substance.
Like fire.
Fire is a reaction and when it stops, it's still made of the same materials.
Doctor Manhatten mentions this on national TV in Watchmen in what I THINK was supposed to be a joke but everyone assumed he was being serious about.
"Well, a dead body is made up of as many atoms as a living one so nuclear war doesn't really matter if you think about it."