Conspiracism is a philosophy of the modern age, a way of thinking that explains the frustratingly random world around us with the idea that it's all happening for a reason.
Unlike with religion, in conspiracism intelligence behind all this isn't divine or supernatural, but very human: extremely powerful, secretive people with immense resources, selfish motives and the willingness to manipulate everyone's lives towards an ill-defined goal of world supremacy.
All arguments against the conspiracy theory are used as evidence of the cover-up essential to the conspiracy's existence. The government has photographic proof of the moon landing? It must be planted. The President actually produces the certificate proving his place of birth? It must be a fake. Someone who knows exactly what happened explains it all in detail? They must be lying.
Conspiracy theories are seductive and infectious. They allow the believers to explain all the things wrong with their lives in a way that doesn't put them at fault. It makes them part of a special club of people who know The Truth.
And perhaps above all it gives them a way to make sense of an unfeeling and directionless world, even if it does so in a way that is profoundly terrifying.
10. The Moon Landing Was Faked
One of the most popular conspiracy theories in the Western world is that the 1969 moon landings were faked on a sound stage, possibly being directed by Stanley Kubrick, to give the United States an apparent victory in the Space Race against the Soviet Union.
A significant argument used by the conspiracists was the absence of photographs of the moon's surface showing the Apollo landing modules the astronauts used. This hit a hurdle when high-resolution NASA photographs were released showing the various space doohickies sitting there perfectly happy on the lunar landscape.
The insanity of attempting to fake such an immense event is the main argument against the conspiracy existing. Analyses have determined it would be more difficult to create and, crucially, maintain the fake than it would be to actually send someone up there.
In particular more than 400,000 people would have to be paid off or coerced to stay silent. But conspiracists are logic-proof, and so this conspiracy theory persists.