One of the problems is we do have massive gaps. Mainly because we have no written records from the Stone Age, and barely anything from certain other cultures. Von Däniken exploits that.

Conspiracies are wonderfully self-reinforcing: anything that doesn’t support the conspiracy is clearly the work of the conspirators hiding their existence.

The problem is that does happen in real life. Intelligence services and organised crime work actively to hide their tracks. As do corrupt officials and some of the military.

We live in a society where corruption is rife and ordinary people are largely excluded from most major institutions ... That is the atmosphere that breeds these things.

My favorite way to cut apart those two is to ask: How many people need to keep a secret, how long and how perfectly would they need to succeed, and what motive do they have to do a good job?

That's a fair question, but we do live in a surprisingly secretive society. I think that shifted over a lot during the Cold War period. It became acceptable to hide large sections of public spending from the public.

We also live in a corrupt society and occasionally that emerges as a scandal.

Certain secrets are kept better than others. Now and then real conspiracies do become public knowledge like the Tuskegee Experiment or Scientology's infiltration of parts of the US government.