"Consider a conspiracy theory like the claim that the Apollo moon landing was a hoax or that 9/11 was secretly planned by President Bush or that the Holocaust never happened. There are such conspiracy theories and they are believed by a reasonable number of people, but all of them require a large number of unproved and individually extremely unlikely assertions to be true simultaneously."

The preceding passage appears on page 105 of a book called, incredibly, Critical+Thinking,+Logic,+and+Argument+by+Eric+Dayton. He's a professor of philosophy.

Making 9/11 skepticism the equivalent of Holocaust denial is a tactic usually reserved for the most pernicious forms of misinformation. This philosophy professor lets the above sentence stand without any explanation.