The discovery of life beyond earth would transform not only our science but also our religions, our belief systems and our entire world view. For, in a sense, the search for extra terrestrial life is really a search for ourselves who we are and what our place is in the grand sweep of the cosmos.
        Contrary to popular belief, speculation that we are not alone in the universe is as old as philosophy itself. The essential step in the reasoning was based on the atomic theory of the ancient Greek philosopher Democritus. First, the laws of nature are universal. Second, there is nothing special or privileged about Earth. Finally, if something is possible, nature tends to make it happen.
        Philosophy is one thing, filling in the physical details another. Although astronomers increasingly suspect that bio-friendly planets may be abundant in the universe, the chemical steps leading to life remain largely mysterious.
        Traditionally, biologists believed that life is a freak ? the result of a zillion-to-one accidental concatenation of molecules. It follows that the likelihood of its happening again elsewhere in the cosmos is infinitesimal. This viewpoint derives from the second law of thermodynamics, which predicts that the universe is dying ? slowly and inexorably degenerating toward a state of total chaos.
        According to the orthodox view, Darwinian selection is utterly blind. Any impression that the transition from microbes to man represents progress is pure chauvinism on our part. The path of evolution is merely a random walk through the realm of possibilities.
        There is, however, a contrary view ? one that is gaining strength and directly challenges orthodox biology. It is that complexity can emerge spontaneously through a process of self-organization. If matter and energy have an inbuilt tendency to amplify and channel organized complexity, the odds against the formation of life and the subsequent evolution could be drastically shortened.
        The relevance of self-organization to biology remains hotly debated. It suggests, however, that although the universe as a whole may be ding, an opposite, progressive trend may also exist as a fundamental property of nature. The emergence of extraterrestrial life, particularly intelligent life, is a key test for these rival paradigms.
        These issues cut right across tradition religious dogma. Many people cling to the belief that the origin of life required a unique divine act. But if life on Earth is not unique, the case for a miraculous origin would be undermined. The discovery of even a humble bacterium on Mars, if it could be shown to have arisen independently from Earth life, would support the view that life emerges naturally.