Excerpt from Complexity by M. Mitchell Waldrop

Indeed, said Langton, by taking this bottom-up idea to its logical conclusion, you could see it as a new and thoroughly scientific version of vitalism: the ancient idea that life involves some kind of energy, or force, or spirit that transcends mere matter. The fact is that life does transcend mere matter, he said - not because living systems are animated by some vital essence operating outside the laws of physics and chemistry, but because a population of simple things following simple rules of interaction can behave in eternally surprising ways. Life may indeed be a kind of biochemical machine, he said. But to animate such a machine "is not to bring life to a machine; rather, it is to organize a population of machines in such a way that their interacting dynamics are 'alive.'