CAN SETI BE JUSTIFIED?
Is SETI a waste of time and money? I do not think so. SETI does at least two valuable things. First, it provides an extraordinary opportunity for a shortcut in our search for life in the universe. For obviously, if we detect intelligent civilizations we will have settled the issue of the possibility of extraterrestrial life, which otherwise may take hundreds, perhaps thousands, of years to resolve, if it can be resolved at all by space travel.
SETI’s chances of success may be slim, but if we do succeed the results would be of the greatest significance. SETI is like a lottery ticket: As long as the investment is small, we have little to lose and much to gain. That is pretty much the way the matter is being treated at the present time -- a budget in the few million over the next decade is a mere pittance as far as those things go.
Second, SETI provides special motivation and in some cases inspiration for many researchers who work in areas related, however indirectly, to the issue of the origin and the evolution of life. Indeed, to be fair to the SETI enthusiasts, much of their work has concentrated on improving our knowledge of several of the links in the chain between the origin of the galaxy and the origin of life. The misleading use of probabilities comes more in the public relations effort than in the actual science.
Another benefit of SETI is that as part of the task of identifying suitable stars it is necessary to improve our star catalogue for distances at least up to a few hundred light years away, which is the maximum radius of the volume that SETI will comb for intelligence in the near future. As new technology--radiotelescopes in orbit, for example-- increases the radius of the search, the map of our section of the galaxy is also bound to improve. This painstaking but necessary job of astronomical taxonomy has been neglected somewhat because it does not compare in glamour with the investigation of the many exciting phenomena that have come to light in the past three decades. SETI gives it the right spice to make it enticing enough.
Whether SETI succeeds or not, however, I suspect that its main possible contribution lies elsewhere. Just as exobiology can provide a very useful context in which to ask questions about the origin and evolution of life, SETI may become a useful framework to examine the nature of our intelligence and our technological civilization. And here I do not mean merely the determination of whether we should feel unique or ordinary as a species -- important as this matter may be -- but rather the ability to bring together many disciplines to investigate the origins and evolution of scientific culture.