After today I promise to move on to other topics. But for today, some final thoughts on the Kennedy assassination and conspiracy theories.

Prolific commenter Richard Greene points out that immediately after issuance of findings by the Warren Commission, something like 87% of Americans accepted those findings. Today, it is more like 30%. What happened?

Put aside for the moment the “anomalies” that I have identified in this series. They are significant, but they are not the most important reason for the change. The most important reason for the change is that we have learned from bitter experience that the criminal justice and national security agencies of our country are only too willing to use their powers to seek to control who runs the government.

From reading the comments on this series, it appears that several people are eagerly awaiting my pronouncement of which theory of the Kennedy assassination I think is correct.

Unfortunately for those commenters, as I said back in Part I, “I don’t have any clear belief as to whether the official version of the events is correct or whether there was a conspiracy.” That remains the case. I have not intended this series as the way to advocate for my own preferred theory, although perhaps inevitably it would be perceived that way. Instead I have intended this series to use the Kennedy assassination as a vehicle to explore the question of how we know what we think we know.

The Kennedy assassination provides an excellent illustration of the proposition that, in considering the truth of a hypothesis, the accumulation of facts consistent with the hypothesis is not nearly as important as those facts, even if few in number, that are at least arguably inconsistent with the hypothesis.

These Kennedy assassination posts have generated large numbers of comments. Most of the commenters, and certainly the prolific ones, have studied up on the issue and have formed firm opinions of their view of the facts. But then there is a large gulf of disagreement between those who have accepted the “Oswald acted alone” theory and those who have rejected it.

The smallest camp is those who admit they don’t know the answer. That’s my camp. Many people understandably do not feel comfortable with ambiguity in situations like this.

Back in Part II of this series, I expressed the view that biggest problem for those who support the official narrative of “Oswald acted alone” is that there are multiple factual anomalies that are at least potentially inconsistent with that theory.

As mentioned in Part I of this series, I don’t have a firm view on whether there was or was not a conspiracy to assassinate President John F. Kennedy. However, if there was such a conspiracy, then clearly that is something that would be significant, and that all Americans would have a big interest in knowing about.

The reason a conspiracy would be so significant is that its very existence would imply that its members foresaw important consequences from the assassination. If the assassination was just the work of a lone gunman, presumably Oswald, then there need be nothing more to it than the mania of one crazy guy. The lone assassin would not need to have any motive beyond the satisfaction of taking out his target, or perhaps the perceived public glory and notoriety of being recognized as the successful killer.

If there is a conspiracy, that completely changes.

In the Kennedy assassination, a problem for conspiracy theorists is coming up with a theory that is plausible.

“Conspiracy theory” — the label evokes connotations of something so preposterous that it couldn’t possibly be true.

With an obvious simple explanation for some incident easily at hand, generally involving a single perpetrator or a natural cause, the alternative “conspiracy theory” posits that a large group of people plotted to bring the incident about. The very size of the posited group alone makes the conspiracy theory seem unlikely, because such a large group could never hope to keep the secret.

And then, in the classic conspiracy theory, the large group of conspirators consists mostly or entirely of agents of the government, who have allegedly acted in nefarious and illegal ways against the interests of the people they are sworn to serve, and have then also covered up their illegal conduct. Our government employees and officials may not be perfect, but surely they would not carry out, and then cover up, massive illegal conspiracies against the interests of the people.

Put these factors together, and you can see why sticking the label “conspiracy theory” on a hypothesis has long been an effective way to dismiss that hypothesis out of hand.