Are We Alone?
Paul Davies
Reviewed by David Bailey
After discussing at some length the history of debates on the existence of extra-terrestrial life, Davies discusses in detail the philosophical and religious implications of this question. Typical of many theologians is E.A. Milne, who asks: "Is it irreverent to suggest that an infinite God could scarcely find the opportunities to enjoy Himself, to exercise His godhead, if a single planet were the sole seat of His activities?" In any event, it is clear that the discovery of extra-terrestrial intelligent life would have incalculable impact on world religious thought.
There are of course detractors who claim that there are no extra-terrestrials -- we are alone. Among these are Brandon Carter, who notes that it has evidently required about 4 billion years, a large fraction of the estimated lifetime of the sun, for intelligent life to arise here on earth. He concludes that the emergence of intelligent life is exceedingly improbable -- we are an accident that barely sneaked in under the wire. Another argument often used by detractors is Fermi's rhetorical question, "Where are they?" In other words, if any other civilization existed, at least within the confines of the Milky Way galaxy, it seems inevitable that it would have long ago expanded its dominion to encompass our solar system and the inviting third planet. Yet there is every evidence that we are the product of evolution on this earth, not the descendants of extra-terrestrial colonists. Thus no other civilization exists -- we are alone in the Milky Way.
Interestingly enough, some of the most vocal detractors of extra-terrestrial intelligent life are found among the ranks of modern biologists, including Mayr, Dawkins and Gould. They insist that evolution is a random walk, stumbling around in every direction, and not in any sense favoring intelligent life. Thus if we humans manage to destroy our species, it is exceedingly unlikely that intelligent life will ever emerge here again. Underlying such arguments is a knee-jerk distaste for the "ladder of progress" or other form of teleology in evolution. Typical of this philosophy is Dawkins assertion, "There is nothing inherently progressive about evolution", and Gould's emphatic statement, "Progress is a noxious, culturally embedded, untestable, nonoperational, intractable idea that must be replaced if we wish to understand the patterns of history."
Countering such cold denials is Kauffman's theory of self-organizing systems, in particular his theory of linked autocatalytic chemical reactions, which he claims are inevitable in any sufficiently complex chemical soup. He concludes that there are many possible routes to life, so that intelligent life must pervade the universe. Kauffman's ideas about self-organizing systems effectively introduce into biology a law of increasing complexity that is remarkably like the "ladder of progress" thought by many to be passe and mistaken. In any event, Davies notes that the discovery of extraterrestrial life would provide powerful support for Kauffman's thesis.
Davies most interesting discussion is on the nature of consciousness. Far from the curious accident of nature that some consider it to be, he believes that consciousness is a fundamental emergent property of nature, a natural and inexorable consequence of the operation of the laws of physics. Along this line, Davies asserts that we cannot ignore the profound fact that the existence of a conscious observer seems to be of fundamental importance in quantum mechanics. Davies goes on to mention some of the "cosmic coincidences" of our universe, which have led physicists such as Hoyle to quip that the universe is a "set-up job", remarkably contrived for the existence of atoms, stars and us. The most common explanation proposed to explain such coincidences is some variation of the "many-universe" theory. But this violates Occam's razor is the most extreme manner imaginable.
Davies also contemplates the mystery of why our minds are able to discover the laws of nature, when such a capacity obviously conveys no evolutionary advantage. Evidently our capacity for advanced mathematical reasoning, and applying such reasoning to understand the basic laws of physics, has lain dormant for hundreds of thousands of years. For that matter, why is the universe so mathematical? -- as Jeans quipped, "God is a pure mathematician". Summarizing this discussion, Davies quotes Freeman Dyson: "The more I examine the universe and study the details of its architecture, the more evidence I find that the universe in some sense must have known we were coming."
The search for extra-terrestrial intelligence can thus be seen as a test of the profound principle that the universe is inexorably progressive, and that the development of consciousness is its evident goal.