The Dark Ages
In order for an environment to be established where this theory could be taught, the world had to first begin to wake up from a thousand years of darkness. A policy of free thinking had to first be established. A government that protected that thinking had to first be established. We now live in a world where that freedom is spreading across the globe while at the same time, being viciously attacked by those that live in fear of it. The United States of America is a country that despite all of its flaws, still protects and defends these rights.