As the 10th anniversary of the assassination of Yitzhak Rabin and its commemorative events approached, a slew of unsolicited emails began turning up in my mailbox. The work of conspiracy buffs stirred into action by the occasion, all proposed fantastical accounts, most of which have circulated for years, about the “true” story of Rabin’s death.

There is no single conspiracy theory of Rabin’s assassination, just as there is none of the assassination of John F. Kennedy. There is rather a hodgepodge of hypotheses, some conflicting and some overlapping. They fall into three categories:

1. Yitzhak Rabin was the victim of a right-wing plot to kill him. Those who believe this argue that Rabin’s convicted assassin, Yigal Amir, was not acting alone as he claimed, but was part of a plot hatched in anti-Oslo agreement circles in Israel’s secret service or Shin Bet, the purpose of which was to cripple the “peace process” by removing the prime minister behind it.

2. Rabin was the victim of a left-wing plot to kill him. According to this theory, the plotters, their ranks alleged by some to have included then foreign minister Shimon Peres, were in favor of the “peace process” and assassinated the prime minister because he was disillusioned with it and wished to renege on it.

3. Rabin was the victim of a double plot – a left-wing one to boost him and a right-wing one that subverted it. In this version, the assassination was planned, with the prime minister’s knowledge, as a staged event from which he was meant to emerge alive, thus winning him public sympathy while discrediting the Right from whose ranks the would-be assassin came from. At the last minute, however, real bullets were substituted for the blanks that were supposed to be fired.

None of these scenarios, it must be said, makes much sense. Theory 1, for instance, overlooks the fact that right-wing plotters in the Shin Bet would have had to know that Rabin would be succeeded by Shimon Peres, who was even more pro-Oslo than the prime minister. To suppose that these plotters foresaw that Mr. Peres would then call early elections, blow a huge early campaign lead, and be defeated by Benjamin Netanyahu is a stretch even for conspiracy buffs.

Theory 2, even if one is willing to believe that a politician with a long and distinguished record of public service like Shimon Peres would lead a gang of assassins, cannot produce a shred of evidence that Yitzhak Rabin was in fact preparing to renege on Oslo. No known act or remark of his in the months before the assassination bears this out.

Theory 3 is also illogical. How could Mr. Amir, who had a long record of extreme right-wing activism, have agreed to fire blanks as part of a left-wing plot? And if he thought he was firing real bullets, where are the two mysterious persons – the left-winger who, unbeknownst to Amir, replaced those bullets with blanks at the last moment, and the right-winger who, at the last, last moment, switched them back again – that this theory calls for?

And yet, although logic rarely gets in the way of anyone wanting to believe in conspiracies, there are undeniably some real things about the Rabin assassination that give the conspiracy buffs encouragement.

There is the fact, for example, that right-wing extremist Avishai Raviv, who was working as a Shin Bet provocateur in the months before the assassination, was Yigal Amir’s friend. There are the documented shouts, by someone on the murder scene, of “Blanks! Blanks!” as the fatal shots rang out. There are the contradictions between the medical report of the doctors who treated Rabin and the findings of the official autopsy.

It is of course possible to explain these and other oddities in perfectly innocent ways. Avishai Raviv (as a court that tried and acquitted him ruled in 2003) may have known nothing about Amir’s intentions. Amir himself may have shouted “Blanks!” in the hope of creating a moment of uncertainty in which he could make his getaway. The doctors may have written their report hurriedly and erred. Such things happen. In the case of the Rabin assassination, they probably did.

Ultimately, as with Lee Harvey Oswald and Kennedy, there are less problems in assuming that Amir was acting alone than in assuming that he wasn’t. And yet the conspiracy theories will continue to multiply not only because, on the far Right and far Left, there are those who take ideological pleasure in them, but because there is at bottom a conspiracy buff in everyone, even in the most rational mind.

In fact, conspiracy theories and rational thought are two closely related activities that spring from the same human need to explain and understand. Behind all science, after all, is the belief that nothing “just happens” in isolation, that everything has a cause, and that the most apparently remote things – the phases of the moon and the movements of the tides, for example – may turn out to be closely connected. It is the scientist’s job to find out by logic and experiment exactly what these connections are.

Conspiracy theories are in this sense a kind of primitive attempt to think “scientifically.” They too refuse to concede that anything could have “just happened” and they too insist on finding grander patterns of meaning in things. The conspiracy buff feels that his intelligence is insulted when he is told that Yigal Amir or Lee Harvey Oswald acted all by themselves; to his mind it is like being told that the tides rise and fall at their own whim. Surely great historic events cannot be just a matter of one man’s caprice! The human mind instinctively sees “conspiracies” everywhere. That is why conspiracy theories will always be with us.

Mr. Halkin is a contributing editor of The New York Sun.