Evolution drug

Drug abuse of celebrities are making sensational headlines. When I wondered why it was so hard for people to stop using drugs, I remembered a book I read many years ago. The book was titled "Food of the Gods", written by Terence Mckenna, a writer who had deep interest in psychedelic phenomena.
In this book he posed an ambitious (perhaps too ambitious) hypothesis that insists upon the relationship between human evolution and a drug substance.
When the most recent ice age was ending, the jungles in North Africa was receding, giving away to green savannas. With shrinking jungles, a certain group of primates, our ancestors, that had dwelled on trees in the jungle, were forced out to live in the open areas of the forest. The first thing they had to do was to find their food. It is not hard to imagine they experimented with new variety of foods, perhaps thousands of them, as they adapted to their new environment.
Among those foods they tried were a strange mushroom growing from the dung^^ of cows. When they ate it, they felt as if their eyesight became clearer. Actually a substance called psilocybin contained in those mushrooms proved to enhance your vision and you can see things with acuity if you take it. It perhaps helped them hunt better, resulting in their more chance to survive than other group of primates who might have been too hygiene conscious to eat anything growing from cows' feces. With a little more of this mushroom, you would feel sexually aroused, which in turn gave them more breeding chances. With further more of it, you would see ecstatic hallucinations. This might have fused their audio and visual senses together, which led to the development of spoken language: ability to evoke pictures in another person's mind through the use of vocal sounds. All these pushed the tribe of mushroom eaters up in the front line of genetic evolution.
If we believe his hypothesis, the drugs like psilocybin are deeply related to our existence. We are basically a brain creature. Our brain are always trying to protect us, make us live longer and happier. Occasionally but rather fundamentally, it works wrong, too. We often become too protective, creating many layers of hard shells, social, personal, whatever, around us to hide inside. Something inside us can't stand the smallness of the world protected in the shell. We begin to wonder what the world outside is like. A substance like psilocybin will melt the hard shell away. Once we peek out the world we get addicted to the openness of the outer world. In fact, LSD was used as an effective remedy for depression maniac. We, especially modern people, may need something that makes us jump just as psilocybin once made our ancestors do. As long as we have desire to break out the shell we cannot abolish these drugs. As a matter of fact, alcohol is a kind of drug of the same effect with less addictiveness. Danger and effectiveness always live side by side. Drugs can be good or bad depending on who and how to use it. Perhaps we had better solve our own problem of our rigid shells before blaming drug users.