Enjolras can't understand what Prouvaire felt, being a phoenix, or giving it up afterward; perhaps he wouldn't be able to even if he'd done the same. Prouvaire sees the world through different eyes than he does.

"Give up? Perhaps -- you'd know, I don't. But I would say you've always had something of the phoenix in your soul, my friend. You see both the fire and the future that arises from its ashes; you rejoice in transformation. None of that is lost."