Maybe the most dangerous thing about the “Illuminati” isn’t that such a master cabal has ever existed, but that some people believe it should and wreak havoc under the delusion they run the world.

However intrinsically loony an idea may be, when people believe it, and act on that belief, it attains a power that can shape reality around it. A simple case in point is Nazi anti-Semitism. The fringe and utterly bogus notion that Jews represented a kind of biological contamination that had to be eradicated root and branch became the operative philosophy of a political regime and as a result millions of people died.