As a boy and teenager in the 1950s and 1960s Paul Davies was fascinated by science fiction and tales of aliens, and like many such teenage boys turned to ufology for 'the evidence'. For quiet a time, like many of us, he was intrigued by the 'evidence' collected by the likes of J Allen Hynek, whose house he visited on occasion. By this time Davies was a post doctoral researcher in astrophysics and was clearly getting seriously involved in the subject.
Needless to say, exposure to actual ufology on the ground, as opposed to the sanitised material in books and magazines soon began to change his mind. There is a brief description of his investigation of a case from Warminster, which showed that a mysterious light was in fact an army flare, but would the witnesses believe that ... ?
More to the point perhaps was his growing realisation that the aliens in UFO reports and their mysterious craft were just not, well, alien enough, they were obviously the product of the human imagination and human concerns. Whatever puzzling UFO reports represented (and he says he keeps his mind open to the possibility that some might represent novel physical and/or psychological phenomena), they did not represent the visits by extraterrestrial.
Davies moved on from this youthful interest, becoming a lecturer in cosmology at the University of Sussex before moving to Adelaide, and becoming the author of both textbooks and popular science works, several with rather edgy agendas moving close to theology. However his interest in extraterrestrial life has not left him, and he is now involved in the SETI project as well as running something called the Beyond Centre for Fundamental Concepts in Science.
Davies is rather more cautious than many writers in this field and continuously points out that our position is one of almost total ignorance, as we do not really know how life originated or whether it is very widespread or extremely rare, perhaps unique to earth. Until we discover completely alien life forms, we will not be able to answer that question. That is not going to be very easy, even if we found primitive life or its relics on Mars, that life could have had a common origin to earths, as meteorites are transferring material from one to the other.
Obviously waiting until we can explore the oceans of Europa or the methane lakes of Titan for 'life' might take a very long time, but there might be a closer location for exotic life forms, earth itself. All known life on earth has a common genetic origin, shares a common ancestry and is part of the one kindred. Might there be other life on earth though, which evolved separately, for example organisms in which phosphorus is replaced by arsenic? Scientists are not searching remote, isolated and extreme environments for such exotic life. If it could be shown that life evolved on earth more than once, then that might be evidence that life is something which arises easily and may indeed be common.
Finding evidence for 'intelligent', i.e. techno-linguistic life, may be much more difficult. The example of earth suggests that it is rare, only one among the billions of life forms that have existed on earth has developed techno-linguistic ability. Davies suggests that science may be even rarer, a product of very special historical circumstances, in particular the fusion of Greek rationalism with Judaeo-Christian monotheism. Indeed not any old monotheism would seem to do, only one where God like the king was bound by his own laws (e.g. England after the defeat of Charles the First). Nature like the Commonwealth is regarded as being bound by laws, administered by a constitutional God.
While this probably overestimates the particularism, and underplays developments within Greek and other protosciences, it does point to the possibly that science may not be universal. A different ideological background might produce a different science, one in which the 'laws' of physics might be regarded as having altered or evolved for example.
When it comes to accumulating evidence for techno-linguistic ETs, the situation becomes worse, and Davies like most previous authors tends towards rather self contradictory arguments: alien civilisations must be much older than ours and possess all sorts of wonderful knowledge and wisdom, but they are assumed to communicate by means of such 20th century products and discoveries such as radio telescopes, lasers, and neutrino detectors. However wild our imagings, space travel, time travel, 'brane-hopping', building universes in the back garden or emulating them on super-super-computers, nanomachines, organic-machine hybrids or giant quantum computers, are all just that, products of the human imagination in our time and culture. Odds are overwhelming that the products of really alien mental activity wouldn't be like anything that human beings could ever imagine.
Given that, the chances of us ever receiving a message through a radio telescope, or finding an alien artefact we could recognise as an artefact must be exceptionally slim. Even if we did receive a message, the chances of deciphering it would seem to be near zero (best case Virgil trying to decipher a textbook on quantum mechanics, more likely a gerbil trying to decipher it)!, and even if by some miracle we could decipher it, it would be irrelevant to the human condition, you know something like "we have found that the perfect path to global peace is to eat each others detachable and regenerable third tentacles", very useful for us!
Perhaps what books like these really reveal is the imaginations of their authors, and Davies, whose website suggests is a personable enough fellow with an interest in a number of semi-Fortean and quirky topics, such as strange geographical enclaves, lets his imagination go into some very murky places.
There is the notion that human beings should aim to transcend the human condition, at first by means of genetic engineering and chemical coshes, so we all become nice and bland, and loose our fire, passion and rage. Then we turn ourselves over to or into machines which aren't machines because they have organic components (Davies does not give any suggestions as to where these organic components might come from, so why does a little voice in my head whisper aborted foetuses), through to slow and plodding planet-wide or Dyson-sphere sized organo-computers, to the ultimate quantum computers. Quantum computers are tricky things however, too much heat upsets them, they have to exist at near absolute zero, so they would have to be in the cold of interstellar space. There they would live in their own virtual worlds solving ever more abstruse mathematical puzzles.
So the future of intelligence is a self absorbed computer with Asperger's syndrome, 'existing', preferably entombed in a glacier of solid hydrogen, on some wandering world, sling shot out from the warmth of its sun and solar system into the boundless cold, darkness, silence and ineffable loneliness of the "unhallowed spaces between the stars". Surely a vision of Hell for our age, compared with which Budd Hopkins' grey vivisectors, to say nothing of the hot fiery devil of the medieval imagination, seem positively benign.
In which case it is with some relief that we learn than "the scientist" in Davies thinks its not altogether unlikely that we are alone.