Ask Dr. SETI ®

William (via email)

The Doctor Responds:
One does not gauge scientific credibility by short-term success in validating a particular hypothesis -- after all, it took more than half a century to produce compelling evidence to support some of Einstein's theories. What marks a field of study as scientific (or not) is the testability (or, more properly, falsifiability) of its underlying hypotheses, and the level of rigor brought to the related experimental design. When we demand the highest possible standard of proof before accepting proffered evidence, we are applying the scientific method -- hence, are practicing science. This is, I believe, what differentiates SETI science from UFO pseudoscience.

The accusation that SETI is based upon a non-falsifiable hypothesis is valid only if one believes that the objective of SETI research is to prove the existence of extraterrestrial intelligence. Any experiment which adopts that goal is poorly designed, because it becomes open-ended. Better to establish a null hypothesis, which it takes only one counter-example to disprove. For example: I would hypothesize that there are no extraterrestrial civilizations that emit artificial electromagnetic radiation which can be detected on Earth, at our current level of technology. Presently (and for more than 40 years), our research supports this hypothesis. But a single confirmed detection would falsify the null hypothesis, thus lending credence to an alternative hypothesis (that we are not alone).

Because we are in our technological infancy, with the power of both our instrumentation and analysis techniques increasing exponentially with time, I would be hard-pressed to advocate termination of any experiment on the basis of null results alone. One can argue that would be equivalent to abandoning space exploration prior to 4 October 1957, on the basis of humanity's inability to achieve orbital velocity.

When Icarus fell into the sea, did humans give up their dream of flight? It took centuries for us to develop the technologies necessary to conquer the sky. SETI science today is probably still trying to soar on wax-and-feather wings. It may be centuries before our technology advances to the level of likely success. Or maybe next year -- we can't know. But, as Phil Morrison said in his seminal SETI article in 1959, if we dont' try, the chances of success are zero.

Other, more poetic analogies have been suggested -- at The SETI Institute, Seth Shostak equates abandoning SETI research to Queen Isabella ordering Columbus to turn back, just three weeks out of port, on the grounds that he had not yet reached India. Which brings up an even more compelling reason for continuing SETI research: the prospect of positive, though altogether unintended, consequences. After all, Columbus never reached India, so his expeditions must be judged a failure!

Similarly, SETI research may never detect extraterrestrial intelligence. However, along the way to failure, these observations have already significantly expanded our knowledge of the Universe. From detection of supernova remnants to the discovery of countless organic molecules in space, SETI radio telescopes are constantly generating new knowledge. The technology we develop for the SETI endeavor has been applied with great success in the telecommunications and biomedical research arenas. Long-duration cosmic observations hold great potential for further serendipitous discoveries, even if we never reach India.

There is one good time to abandon the SETI enterprise -- when it is no longer producing unexpected results. If we understand everything we detect, and are not seeing anything that we cannot explain -- in short, if we are stagnating -- then the search no longer serves a useful purpose. That's not the case now. There's lots we don't understand, and can't begin to explain. This is a good place to be, if our intention is to learn more.

I have heard SETI called a religion. Although I don't see it as such, there are certainly parallels, with which I for one am entirely comfortable. Many people of religious faith see SETI science as compatible with their beliefs -- for example, Father Theodore Hesburgh (president emeritus of Notre Dame Univ.) has long said that a search for extraterrestrial intelligence is an attempt better to understand God and His creations.