Michel Morange

Life Explained? 50 Years After the Double Helix Publication date : April 1, 2003

Fifty years ago, Francis Crick and James D. Watson proposed the double-helix model for the DNA molecule, the structure responsible for heredity. They believed they had, as Crick put it, discovered “the secret of life”. He was so widely believed that until recently hardly anyone bothered to ask, “What is life?”, and even fewer considered replying. The question had become not only unfashionable but also taboo. Such is no longer the case. “What is life?” has become all the rage.

The primary goal of this book is to account for the revival of a question that had been left by the wayside during the recent period of upheaval in biology. Many of the changes remained unnoticed by the general public, as if molecular biology was frozen around the idea of the double helix. But the revival of the question “What is life?” is also the result of events that are extraneous to biology, such as the development of astrobiology, i.e. the search for life on other planets.

Today’s answers are to be placed in the context of a rich philosophic and scientific tradition, of which we briefly remind the reader. Even more interesting are the answers implicitly provided by the work of contemporary biologists.

From the range of both explicit and implicit replies to the question “What is life?”, there arises a powerful consensus about the basic characteristics shared by all living creatures, and which underlie the very foundations of life. But this consensus quickly evaporates when the various characteristics in a hierarchy must be classified and organised, i.e. when one characteristic must be placed on top and thus regarded as consubstantially linked to life. We show that life cannot be reduced to any one of its isolated characteristics, but that, nonetheless, the solution to the enigma of life should not be looked for in the “beyond”.

Our main goal has been to further thinking about a question which is seldom tackled directly in scientific literature. We hope to help re-establish the link between scientific and general culture.