The Greeks had two words for «life»: bios and zoe. Bios represents the biological and individual sense of life, the life that pulsates within any one organism. This is the only notion of life that is to be found in the philosophy of Ayn Rand. Zoe, on the other hand, is shared life, life that transcends the individual and allows participation in a broader, higher, and richer life.
In Mere Christianity, C. S. Lewis remarks that mere bios is always tending to run down and decay. It needs incessant subsidies from nature in the form of air, water, and food, in order to continue. As bios and nothing more, man can never achieve his destiny. Zoe, he goes on to explain, is an enriching spiritual life which is in God from all eternity. Man needs Zoe in order to become truly himself. Man is not simply man; he is a composite of bios and zoe.
Bios has, to be sure, a certain shadowy or symbolic resemblance to Zoe: but only the sort of resemblance there is between a photo and a place, or a statue and a man. A man who changed from having Bios to having Zoe would have gone through as big a change as a statue which changed from being a carved stone to being a real man.
The transition, then, from bios to zoe (individual life to personal, spiritualized life; selfishness to love of neighbor) is also the transition from a Culture of Death to a Culture of Life.