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Book Review:
Are We Alone?

reviewed by Alex Antonites
email marie @

Philosophical Implications of the Discovery of Extraterrestrial Life

by Paul Davies (1995)
Davies argues that SETI is challenging a longstanding view that the universe is dying -- a view influenced by the degenerative effects generated by the 2nd law of thermodynamics.

In the chapter A Brief History of SETI , Davies pays attention not only to contemporary SETI projects like that of the Planetary Society, the SETI Institute and others, but shows that among the Greek and Roman philosophers we already had the first rational attempts to justify the existence of ETI. His discussion of the Roman philospher Lucretius and the Greek atomist philosopher Epicurus in this respect, is quite well done. When he comes to the 20th Century he concludes that it is especially the post war spurt of technology and science which rekindled interest in SETI, after the first part of the 20th Century when ETI was found mostly in fictional literature. He singles out the advances in the understanding of the chemical basis of life, the discovery of the structure of DNA and the subsequent cracking of the genetic code.

The origin of life became a serious subject of scientific inquiry, and so by implication did SETI. Given the right conditions and appropriate chemicals, life could emerge not only spontaneously on Earth, but other planets as well. After referring to Frank Drake's Project Ozma and others, Davies emphasizes that the discovery of even a single example of extraterrestrial life would be immensely significant to the theory a of chemical and inevitable consequence of the outworking of the laws of chemistry and physics , given the right conditions. Such a discovery could be life in extraterrestrial rocks : "Undoubtedly the definite discovery of say, a non-contaminant living bacterium inside a meteorite would be immensely exciting and important."

Just after the publication of this book in 1995, Goldin and McKay of NASA and Stanford University announced their findings on rock ALH84001 from Mars! Debate on possible contamination continues to this day.

When one reads this book and compares it to others written on extraterrestrial life, I think what makes this book so much interesting is that it justifies SETI from a new scientific paradigm, and that is chaos/complexity theory. This appears in almost all chapters of this book. Coherent with this, Davies philosophically criticizes classical-causal determinism which led to a mechanist paradigm in science. Here the reader must not deduce that Davies rejects the pinciple of causality in science -- far from it. What he states is that the causal principle (which -- in my view -- is the basic mechanism of natural selection) is incomplete. It is to be completed by the principles of spontaneous self-organization. This rather supports a progressive self-organizing universe (not a dying one) celebrated in the works of the Nobel Prize winner Ilya Prirogine and Ernst Janisch. This makes it understandable why Davies has a much more optimistic approach to SETI than, e.g., Dawkins and Gould.

One can discern this line of his thinking in the chapter Extraterrestrial Microbes. Here Davies discusses three philosophical positions concerning the origin of life:

  1. miracles. He explains why he rejects this
  2. improbable accident which he also rejects.
  3. inevitable outcome of the working of laws of physics and chemistry which he supports in conjunction with chaos/complexity theory.
The third position is what most SETI scientists support and this in turn depends on three philosophical pillars: a) Principle of the uniformity of nature: Laws thoughout the universe are the same; b) Principle of plenitude: that which is possible in nature tends to become realized (this has already been invoked by Lucretius in his argument for other inhabited worlds!); c) The Copernican principle of mediocrity: The Earth is not special in position or status in the universe; it rather is a typical planet aroused a typical sun in a typical galaxy.

If life was to be the outcome of a complete random accident of infinitesimal probabilities as Position #1 maintains, then it is almost certain that there is no other life within our horizon. As opposed to this, Davies then joins with Carl Sagan and Stuart Kaufmann. Sagan defends the thesis of the abundance of life in the universe; Kaufmann works out the thesis of self-organization which Davies then argues will support the widespread occurrence of life in the universe.

Life is much more probable than the simple solutions of random molecular shifts would indicate. Matter evolves naturally along certain pathways of evolution leading to states of ever greater complexity:

"When complexity crosses a certain threshold a system may said to be living. There are many ways that chemical (and maybe non-chemical) processes can self-organize to the point at which life emerges, so we should not expect extraterrestrial life to resemble our own in its basic chemistry. If this so it is likely that life can evolve in a wide range of environments. There is no need, for example, to demand liquid water or carbon."
Thus Davies is not what Carl Sagan called himself, a carbon chauvinist.

In Alien Message Davies explores the consequences of the detection of an alien signal. Like Carl Sagan, Davies is also interested in the relationship between science and religion/theology. There are no conclusive theological reasons against SETI, and a signal would support the view that humans are not the pinnacle of evolutionary advance in the universe . Such a detection would discredit the hypothesis that life is the result of a highly improbable random accident.

In Against Aliens Davies examines the arguments of certain philosophers and other scientists against SETI. They are these three:

  1. the anthropic principle
  2. the Fermi's 'where are they?'
  3. the Neo-Darwinian argument of contingency.
He argues in order to demolish all three.

Brandon Carter and Frank Tipler's arguments depends on the formation of life as an exceedinly improbable event. In this respect Davies refers to the lively correspondence between Carl Sagan and Tipler. The Neo-Darwinist contingency argument assumes with many biologists that the course of evolution does not follow any law like trend , but is purely random -- indeed a blind watchmaker, a thesis defended by Richard Dawkins and Stephen Jay Gould. Intelligence is a purely chance phenomenon, exceedingly unlikely to arise elsewhere independently. The contingency thesis strongly depends upon certain philosophical presuppositions.

I think what Davies is trying to say here is that both Dawkins and Gould are over reacting against the Argument by Design. Of course design cannot be a scientific principle, but saying that, it does not follow that there is nothing progressive in evolution, that everything is pure chance -- even if interpreting it as accumulation as Dawkins does. Over against Dawkins, Gould and in a sense also Tipler and Carter, Davies enlarges causality with self-organization and spontaneous origins of life and order. The key property of self-organization lies at the edge of chaos, where systems can suddenly and spontaneously create organized complexity with surprising efficiency. Davies thus rejects both explanation by miracles and stupendously improbable molecular accidents. Self-organization can do the trick!

"None of this is to say that Darwin is wrong: merely incomplete. Nor does it claim that evolution is directed towards some pre-ordained goal ." Contingency for Davies does indeed play a large part in the details of evolution. But the same general trend that can lead to the emergence of life and mind on Earth, also can take place elsewhere in the universe. Evolution is surely not haphazard, accidental, but biological convergence (e.g., the eye) and physical - chemical laws plays a large ordering role.

In The Nature of Consciousness Davies points out that we humans are made of star stuff. He then defends what can be called a Platonic grounding of mathematics. Like Marvin Minsky (of MIT), although not with exactly the same arguments, Davies by implication (Minsky is more explicit and direct on this ) explains why extraterrestrial would do basically the same mathematics as us. It has to do with an underlying order in the universe -- a cosmic connection as he calls it. The ability to do mathematics is not a mere accidental trivial detail.

In Alien Contact and Religious Experience Davies pays attention to the UFO phenomenon. He states that observers of UFO's are mostly genuine honest people of integrity. However he sees this as a deep seated religious need behind the experiences which he think is subjectivistic and not objective. It is a modern variant of a complex of experiences that infuse the folk memories of all cultures through many ages.

I think this book is highly recommendable, especially for members of the SETI League. It will most surely stimulate further discussion and thinking and rethinking. Some chapters are better than others ( I think he could have made much more on the implications in event of the detection of an extraterrestrial signal--this would give his kicking off with the Greek philosophers a good round off), but in the main a well-argued book -- from a philosophical perspective.

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