I must confess that once upon a time, I was a firm believer in a conspiracy in the assassination of JFK. I was quite skeptical, mind you, of theories implicating the CIA, the FBI, LBJ, or any other notorious set of initials. But I was convinced that Oswald could not have acted alone. Not because I was prone to believe in conspiracy theories in general, but because I just couldn’t get around that seemingly impassable roadblock of the “magic bullet”. Therefore, I concluded that since magic bullets don’t exist, there must have been at least one more shooter. And whenever you have two or more people involved, you have by definition a conspiracy.

I had fallen prey to a type of fallacy that I call the fallacy of single explanations: the rush to a conclusion based on the assumption that just because a particular explanation is the only one you can conceive of under the circumstances, it must be the only explanation possible. You also could call it the fallacy of incomplete data, since these faulty conclusions result from trying to bridge the gap when there is missing information.

The “magic bullet theory”, like many other single explanation fallacies, depends on the presumption that normal conditions apply (when in fact “normal” conditions are largely a myth). But there is one little fact about that fateful day that many people do not consider, a fact involving the seats in the presidential limo ; and it makes all the difference.

The president was seated in the rear on the passenger side. And the seat in front of him was occupied by Texas governor John Connally. The latter stood 6’2″, and would have somewhat blocked the crowd’s view of the president under “normal” circumstances. Fortunately, the governor was seated in a folding jump seat that was offset from the president’s seat and also sat down lower.

Moreover, neither Kennedy nor Connally simply sat staring straight ahead like crash test dummies; both were turned in various directions, waving to the crowd and talking to their wives and each other. (Just before the bullets were fired, Texas First Lady Nellie Connally turned to the president and said, “Mr. President, you can’t say Dallas doesn’t love you”, to which he replied, “No, you certainly can’t” — his final words.) Add up all of this, and we see that it was indeed possible for a single bullet traveling in a straight line to do the damage it did to both men. This, mind you, does not conclusively disprove a conspiracy; but it does mean it’s at least possible that Oswald was the only gunman.

There’s also, as you no doubt are aware, a widespread theory that the moon landing was faked. And one bit of key evidence the theorists often cite is a peculiarity in certain photos taken on the moon. In some of these, the flag appears to be waving in the breeze — and there would be no breeze on the moon. Voila! Clearly a fraudulent landing, right? It never seems to have occurred to the conspiracy theorists that NASA would be bloody well aware there is no wind on the lunar surface. It strains credibility just a bit to think that a large consortium of scientists and technicians who are sharp enough to put men on the moon (or fake it) are also so stupid that they would try to pass off a laughably staged photograph. So there just might be some other explanation for the way the Star-Spangled Banner appears. And indeed there is.

Being aware that there is no wind on the moon, NASA knew that planting a flag there would just cause the flag to hang in a rather limp and uninspiring fashion. So they rigged up a support for it that would make it stand out. When the moonwalkers planted the flag, the brace initially wobbled and jittered before gradually settling down to its final rigid position; by then the astronauts had already snapped photos of it, appearing to flutter in a nonexistent gust of air. (It should be apparent if you look at the photo closely that there is a rod on top of the flag.)

Another photo the conspiracists brandish shows the reflection of one astronaut in the helmet of the other, and neither is holding a camera in his hands. Therefore there must be someone else taking a photo, right? Maybe a guy standing on the grassy knoll. Since the third astronaut stayed inside the capsule, they must not have been on the moon at all. Talk about one giant leap in logic for a man (or woman).

But all you have to do is look at the photo a little more closely. See the camera attached to his chest? That’s where the cameras were positioned — not in the astronauts’ hands.

All kinds of conspiracy theories are spawned from the fallacy of single explanations, including, alas, holocaust denial. One such line of “thinking” is based on some flawed calculations about the land area of Germany, and the number of holocaust victims, and the subsequent conclusion that the nation simply would not be big enough to contain so many graves. Therefore, the holocaust must be a hoax!

This bizarre argument overlooks quite a number of facts. For one thing, not all of the deaths or burials took place in Germany. Some of the major concentration camps, for instance, were located in Poland. Second, the Nazis were not particularly fussy about giving their victims respectable burials in private graves; they instead just dumped a mass of bodies into a pit — sometimes an extremely huge pit. Third, a great many of the victims were later exhumed from their makeshift graves and the bodies were burned and the bones ground up to conceal the evidence of the genocide. Fourth, lest anyone forget, there were the notorious ovens that disposed of many, many, many of the holocaust victims.

Sometimes the fallacy of single explanations is practiced in a different way — not so much in ignoring alternate explanations as in ignoring alternate premises on which the explanation is based. (While it is not the same as the fallacy of the single cause, the two can work together.) The classic example is the “prime mover” argument that’s supposed to “prove” the existence of God. It’s a fallacy that even some of the greatest thinkers have fallen for. It goes something like this: everything that exists or happens must have a cause; therefore there must be something that sets the initial cause into motion. There must be, in other words, a prime mover, or God.

Aside from the fact that this argument is self-contradictory — it declares that everything must have a cause, and therefore, there must be something that doesn’t– it’s based on a premise that is not only unproven but patently false: namely, that everything has only a single cause. In fact, everything has an untold number of causes. Furthermore, as we now know from modern physics, time is not a linear process; it would make just as much sense to say that the “effect” is really the cause of the “cause” as vice versa.

In short, the fallacy of single explanations is what happens when reductionism runs amok. Occam’s Razor is a useful tool, but only if you use it properly — if you flash the razor around willy-nilly, somebody might get hurt. Occam’s Razor, as articulated by William of Occam (or Ockham), states that “pluralities should not be posited without necessity” — in other words, things shouldn’t be made any more complicated than they have to be. (Even Einstein reportedly emphasized this point.) Thus, given two competing theories, the simpler one is generally to be preferred.

This presupposes, however, that all of the relevant facts are available. Occam’s Razor is not a valid excuse to discard information. Furthermore, note that the above examples violate the principle by opting for the more complicated explanations. Positing the existence of a Supreme Being as the explanation for the existence of the universe presents us with the problem of having to explain the existence of the Supreme Being, which is at least as difficult. (It’s ironic that William Of Occam was a champion of the simplicity principle, since he was a theologian, and religion often goes against the grain of such a concept.) And the possibility of a large, well-organized, secretive conspiracy to deceive the public is much trickier than the propositions that NASA landed men on the moon, and a solitary wacko murdered the president. (According to one survey, most of the people who believe the moon landing was faked also believe extraterrestrials have visited earth. Evidently they think it’s easier to travel untold millions or billions of miles than to travel 240 thousand miles.)

Before we jump to a conclusion about the likelihood (or, as is generally the case in today’s world, the absolute infallibility) of a certain explanation, we would do well to make certain we dig for all the relevant facts; and that we aren’t offering an explanation that is needlessly complicated in comparison to the alternative(s).