Editing UFOs An International Scientific Problem (section)

== Matters of Definition ==
It would seem logically necessary to frame, early in any discussion of
the "UFO problem" a working definition of what shall be understood by "an
Unidentified Flying Object." The effort quickly entangles one in semantic
difficulties of a more or less obvious nature. Clearly, untrained observers
can report as a UFO a wide range of things seen in the sky or moving near the
earth's surface or even resting on the surface in un-flying manner. Fireballs
(meteors brighter than -5 magnitude by present astronomical definition) consti-
tute a good example; many persons are quite unfamiliar with the phenomenology
of fireballs and bolides, and will turn in sincere and often rather accurate
descriptions of fireballs under the claimed heading of UFOs. Aircraft running
lights, aircraft landing lights, aerial reconnaissance strobe lights, re-enter-
ing satellite debris, bright planets, and a wide miscellany of other sources
of night-luminous objects are reported from time to time as "UFOs". The U.S.
Air Force, and various persons who scoff at the notion that there exists a
scientifically significant UFO problem, are entirely correct in suggesting
that many UFO reports fall into this category. Only a little experience in
querying observers makes clear that, of all reports that temporarily bear the
label "UFO", a substantial fraction are, indeed, misidentified natural or
technological phenomena of such types. There is plenty of noise mixed in with
whatever real signal may exist; that this is so need not surprise any scien-
tist. Noise-filtering is a standard problem in many areas of research.

The "UFO problem" which I have come to regard as so extremely important,
centers around that portion of all reports of initially unidentified objects
which is left as a residuum after the bulk of inadequately reported or
obviously misidentified phenomena is filtered out. Only a little reflection
on the foregoing remarks reveals that it is scarcely a clear-cut definition.
Nevertheless, it may afford an initial basis to begin discussion.
A curiously similar definitional problem arises in dealing with the class
of "ball lightning" reports. In the literature one can find reports of lumi-
nous masses, tagged as "ball lightning", that span so broad a range of phenom-
ena that one must be quite careful that he is not subsuming many diverse phe-
nomena under that single heading. The situation with respect to "ball light-
ning" turns out to be similar to that for "UFOs" in the further significant
sense that the basic nature of each phenomenon is not yet clearly understood,
so that clear-cut working; definitions are simply not yet possible. Such a
situation is really not new in science; think of the semantic ambiguity, in
earlier days of science, centering around such terms as atom, compound, force,
species, e ther, disease, meteor, etc.

In point of fact, the above definitional problems cause rather less
trouble in scientific discourse on the UFO problem than a philosopher might
predict. So let's proceed.