With rare exceptions, scientific journals do not publish reports of UFO observations. The decision not to publish is made by the editor acting on the advice of reviewers. This process is self-reinforcing: the apparent lack of data confirms the view that there is nothing to the UFO phenomenon, and this view works against the presentation of relevant data. If a bizarre phenomenon is reported–sometimes in colorful and emotional terms–in the popular press, and if sober accounts of the same phenomenon are never documented in scientific journals, scientists may understandably come to believe that the reports are spurious: at best, misperceptions of familiar objects and phenomena, and at worst deliberate hoaxes perpetrated on an uncritical public.

Any scientist who spends a small amount of time investigating the subject will soon realize that many of the simpler and more credible reports can, indeed, be interpreted as mirages, weather balloons, and other familiar natural phenomena and technological devices. Further study may turn up dramatic reports that, if they are to be believed, indicate that the earth is being visitedby members of a very advanced civilization, which is therefore presumed to be alien and extraterrestrial, traveling in craft that behave in a fantastic manner. When faced with such a possibility, the scientist tends to look at the implications of such a hypothesis. In making his deductions, he has available a great store of information concerning the solar system, the universe, laws of physics, and conditions in which living organisms can survive. Using this information, the scientist may well conclude that the hypothesis must be rejected.

An example of this type of argument is advanced by Condon himself (Condon & Gillmor, 1968, p. 28). Starting from the assertion that an alien civilization must originate on a planet of the sun or some other star, Condon argues that a civilization based on a planet attached to a nearby star would not set out on a journey to earth until the civilization knows that an advanced technology has been established here. From this consideration he estimates that there is no possibility of such a civilization visiting earth in the next 10,000 years. Concerning the solar system, Condon takes the view that only Venus and Mars might provide possible abodes for life and argues that our knowledge of these planets provides no evidence for the existence of advanced civilizations on these planets.

It appears, therefore, that the difference in attitude toward the UFO phenomenon on the part of scientists and members of the public may to some extent be understood in terms of the stricter demands of evidence and proof required by the former, and in part by the large amount of information available to the former that tends to argue for interpretation in familiar terms and against explanation in terms of alien civilizations. However, there may well be other factors influencing scientists’ attitudes, such as the fear of ridicule. Further comments may be advanced concerning the attitudes of particular groups of scientists. For instance, physicists appear to attach importance to single conclusive cases: the evolution of physics is marked by such milestones as Thomson’s demonstration of the particle nature of cathode rays, Davisson and Germer’s demonstration of the wave nature of the electron, etc. This