Except perhaps for critical intelligence, nothing stands out from the rest of nature more impressively than the life-world. And nothing provides more occasion for wonder. Especially interesting is the question of how life began. In fact, the question of life's origin is still one of the most challenging and exciting in all of natural science. Proposals about how life emerged from non-living physical antecedents are as abundant as they are unconfirmed. Did life begin, for example, with cycles of self-replicating RNA? Or from a prebiotic protein matrix? Did it emerge in direct continuity with the self-organizing tendencies of physical processes? Is the origin of life perhaps just one step in a whole series of emergent stages in cosmic process?

Whatever the chemistry, physics and mathematical principles that underlie the origin of life may be, it still remains puzzling that in the arrival of living beings the universe made an abrupt and radical departure from the inanimate physical routines that had prevailed beforehand. Life is so unlike nonliving states of being that our religious ancestors spontaneously attributed its existence to a mysterious divine agency. Quite understandably pre-scientific humanity interpreted life as a perpetual miracle.