Terence McKenna believed that it was because some of the apes discovered and started eating psilocybin mushrooms. It was his theory that as the climate changed, and the rain forest receded into grasslands, some of the apes started eating these mushrooms as a regular part of their diet, and along the way they developed new ways of thinking.
If you’ve ever done mushrooms, then you probably know some of the logic behind his theory.
At low doses, psilocybin actually increases visual acuity, and makes you horny.
An increase in visual acuity would make you a more effective hunter, and the horniness of course would cause you to breed more often.
What these mushrooms do at high doses is that they give you a completely different way of looking at the world. Like a giant pause button that allows you to step out of a scene, and take a fresh look at it, free from the constraints of normal patterns of thinking, and even your own preconceived notions of yourself.
You can achieve some fascinating revelations when you’re on them.
So what you would have if our ancestors started eating these things on a regular basis, is a bunch of really aware, thinking, horny apes that can see really well.
Now, I’m no scientist, but that sounds like a recipe for evolution to me.
Who knows whether he was right with this theory or not, but we do know that the evolution of the human animal is the most puzzling thing in all of nature.
The greatest mystery in the entire fossil record, without question, is the doubling in size of the human brain over a period of 2,000,000 years.