Editor's Note: What follows is an excerpt from a more substantial presentation by Dr. Tough at the International Academy of Astronautics "SETI Science and Technology" session in Amsterdam, October 1999. The full paper may be found online at <http://members.aol.com/AllenTough/strategies.html>.
SETI -- the scientific search for extraterrestrial intelligence -- has reached an interesting stage. Having relied primarily on a single strategy for 40 years, the field is now actively considering a wider array of promising options. This is a highly appropriate change. There are at least seven reasons why it is appropriate for the SETI field to widen the array of search strategies that it encourages and supports.
First, the history of scientific discoveries teaches us the value of widening the array of research methods. It is quite common for a breakthrough to result from a new, fresh, unorthodox strategy or research method.
Second, the SETI field is trying to detect something that is totally unknown and presumably deeply alien. We do not even know whether we are searching for artificial machine intelligence, biological intelligence based on flesh-and-blood brains, or some advanced integration of the two. We have no idea of the origins, history, thought patterns, emotions, ethics, core values, purposes, technological capacities, or other major characteristics of extraterrestrial intelligence. It is likely that ETI will turn out to be surprisingly different from what we expected--deeply alien, puzzling, unlike anything we have ever encountered before. It has, after all, likely advanced to a level of knowledge and technology that is thousands or millions of years beyond our current human level. Faced with such a profound unknown, an attitude of humility and scientific open mindedness seems appropriate. The pursuit of a somewhat diverse array of search strategies seems wiser than keeping the methodology too narrow.
Third, we must remember the likelihood that more than one extraterrestrial civilization is available to be detected. It is all too easy to think only about the first detection, ignoring the likelihood of multiple detections over time. The start of a new millennium is a good opportunity to look ahead at the likely pattern of detections over the next thousand years. If several civilizations exist in our galaxy, as most SETI scientists hypothesize, then we may detect several of them during the next millennium. For example, we may detect an artificial radio signal and an encyclopedic laser message and a large probe parked in the asteroid belt and a tiny probe near the Earth's surface.
Fourth, widening the assumptions and strategies of the SETI field may reinvigorate the people, conferences, and writing in the field. Fresh ideas and bold conceptualization, some attention to long-term visions, and a wider variety in conference papers can retain the field's intellectual excitement and avoid a feeling of boredom, fatigue, and disappointment.
Fifth, science and technology have changed greatly in the 40 years since the SETI field chose radio telescopes as its key strategy. That was a logical choice 40 years ago. Radio telescopes were just becoming popular among astronomers, two eminent scientists wrote a paper urging their use for SETI, and a distinguished engineer wrote a paper claiming that interstellar propulsion is impossibly slow and expensive. But our scientific and engineering knowledge today is dramatically different from what it was 40 years ago. Today's decisions about appropriate strategies should be based on the science and technology that we can confidently anticipate today, not on 1959 science. Today's choices have to take into account our recent advances in such fields as computer science, artificial intelligence, robotics, surveillance methods, molecular manufacturing (nanotechnology), propulsion, space exploration, lasers, and fiber optics.
Sixth, although the SETI field is 40 years old, it has not yet produced any confirmed evidence of ETI. That fact points up the need to expand the array of search strategies. Fortunately, several fairly new and highly promising strategies are readily available.
Seventh, there is no need to let the reputation of the UFO field frighten us into unduly restricting our own strategies. All of us in the SETI field worry about being confused with the UFO field. We encounter this confusion in our classrooms, at the faculty club, at social gatherings, in legislatures, and in donors' offices. But there is no need to let our fear and anger lure us into poor decisions about our own scientific strategies. If our sober assessment concludes that smart probes could have readily reached our solar system, for instance, then we should have the courage to search for them. To reduce confusion, we should frequently point out that our scientific approach differs from the UFO field in three key ways: (a) we are deeply committed to skepticism, verification, peer review, and the scientific method, (b) we build in strict safeguards against hoaxes, self-delusion, and erroneous data, and (c) we adopt protocols to avoid premature and immodest claims.
All in all, a reasonably wide array of search strategies seems likelier to lead to success than reliance on just one or two. The phenomenon we are trying to detect is so unknown, so old, so advanced, that we cannot be sure which of our strategies is most likely to succeed. Faced with this situation, we should proceed vigorously with all promising strategies in order to enhance our chances of achieving contact.
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