Science, as always, is trying to catch up with curiosity, and explain why our bodies are so uniquely affected by marijuana. The more we learn, it seems as though our bodies were made for marijuana or vice versa.
The theories around why human bodies have adapted to the active chemical in cannabis range from the biological to the spiritual. In Food of the Gods by Terrence McKenna, McKenna raises the point that marijuana might even be the original tree of knowledge. The truth may not be so glamorous, but whatever it is it ties the human body and the cannabis plant together through millions of years.