Conspiracy theories surround us. Witness the reactions on the Internet to the tragic and mysterious disappearance of Malaysia Airlines Flight 370. Perhaps North Korea hijacked the plane. Perhaps the Chinese are responsible. Maybe aliens did it.

Or, as an influential legislator in Iran contended to the New York Times, perhaps the U.S. "kidnapped" the lost plane in an effort to "sabotage the relationship between Iran and China and South East Asia."

Pick your topic: Ukraine, the National Security Agency, assassinations of national leaders, recent economic crises, the authorship of Shakespeare's plays — it's child's play to assemble a host of apparent clues, and to connect a bunch of dots, to support a relevant conspiracy theory. In recent years, for example, many Americans have become convinced that the United States (or Israel) was responsible for the attacks of Sept. 11, 2001, that the U.S. government concocted HIV/AIDS, and that federal agencies have conspired to hide the association between vaccines and autism.