Before Nicolaus Copernicus realised that the Earth was not at the centre of the universe, the accepted wisdom was that this was the case. Millions of people believed that the Earth was at the centre as it is self evident – from an observer stationed on the Earth, everything else in the universe seems to revolve around us. It is self evident and it is utterly wrong.
In 1796, a Frenchman by the name of Georges Cuvier, wrote a book called, “Notes on the Species of Living and Fossil Elephants”. In this book, for the first time ever, was the theory of animal extinctions put forward. Prior to this scholarly work, it was almost universally believed that no animal species ever entirely died out. The rationale behind this thinking was: to what end would God create a species only to wipe them out later? It was uncomfortable for religious minds to contemplate a capricious God who could arbitrarily extinguish one of His creations. We now know that species do indeed become extinct.
The number of people who believe in an idea has no bearing on the validity of that idea. When someone says, “Well, millions of people can't be wrong”, the correct response should be, “Yes they can. They have been before, are today and will be in the future.”.