People have speculated about the existence of intelligent extraterrestrials for millennia. Basalla provides an overview of attitudes to the subject from the earliest times to our own day, and comes to fairly negative conclusions. There has always been, he thinks, a considerable element of wishful thinking in our attitudes to the possibility of alien civilizations.
The early chapters move fairly rapidly from the mediaeval cosmos, via Kepler and Galileo, into more modern times. By the nineteenth century it was obvious that there could not be life on the Moon, and interest shifted to Mars, which seemed a better bet. Schiaperelli believed that canals were visible on Mars and this idea was taken up and strongly advocated by Percival Lowell in the early twentieth century. By the time that space travel to Mars became feasible the existence of the Martian canals was already long disproved, but arguments about the existence of microscopic life forms on Mars continued and is still going on today.
For much of the twentieth century the dominant scientist active in the search for extraterrestrial life was Carl Sagan, whom Basalla regards as Lowell's successor. This is a somewhat damning comparison, although Basalla does acknowledge that Sagan was the better scientist and was less dogmatic than Lowell. He finds that there were two sides to Sagan, who was simultaneously a sceptic, debunking frauds and loose thinking, while indulging in wild speculations of his own.
If there is no advanced civilization, past or present, to be found on Mars, what about on planets outside the solar system? The obvious way to test this seems to be to search for radio signals from outer space. Not everyone agrees about the usefulness of this exercise or about the justification for providing funding for it. Basalla gives a useful account of the politics that have attended the various attempts to conduct searches of this kind, culminating for the moment in SETI.
One of the most respected evolutionists of modern times, Ernst Mayr, was unpersuaded by arguments for the existence of intelligence outside Earth. He pointed out that the great majority of species on Earth have got on perfectly well without acquiring superior intelligence and the possession of a large brain comes with a large biological price. There is therefore no necessary trend in evolution towards the development of intelligence. Other prominent evolutionists, however, have been more supportive.
Even if intelligent aliens do exist, what would they be like? Basalla detects a constant trend towards picturing them as more or less like ourselves, mentally if not physically. (And some scientists, such as the evolutionist Simon Conway Morris, do think that they would probably be more or less humanoid even physically.) Anthropomorphism, Basalla thinks, has been the dominant characteristic of nearly all scientific thinking about aliens.
Basalla show, fairly convincingly I think, that there has often been a religious element in the quest for alien life; indeed, some of the scientists involved have acknowledged this explicitly. There is a sense in which the aliens could be seen as gods; they are often expected to be able to provide us with advanced scientific knowledge and they could even have a salvific role by teaching us how to avoid destroying our own civilization.
Rather disconcertingly, perhaps, the same idea appears in claims by UFO contactees to have been given messages by aliens in space crafts. Could this be seen as a parodic form of the "respectable" scientific search for alien life?
Although he does not say so explicitly, I am left with the impression that Basalla thinks that the whole enterprise is a waste of time. Nevertheless I shall continue to run the SETI programme on my computer, because the possibility that alien intelligence does exist cannot be confidently dismissed and unless we look for it we have no chance of finding it. And perhaps Basalla is not a wholly dispassionate commentator. He fails to mention that the much-maligned Sagan did on one occasion, with a colleague, pick up signals that appeared to come from outer space, though unfortunately they were never repeated.
15 May 2006