If artificial selection can make such major changes in so short a period of time, what must natural selection, working over billions of years, be cap… - Carl Sagan

Who are we? Where do we come from? Why are we this way and not some other? What does it mean to be human? Are we capable, if need be, of fundamental change, or do the dead hands of forgotten ancestors impel us in some direction, indiscriminately for good or ill, and beyond our control? Can we alter our character? Can we improve our societies? Can we leave our children a world better than the one that was left to us? Can we free them from the demons that torment us and haunt our civilization? In the long run, are we wise enough to know what changes to make? Can we be trusted with our own future?

Science invites us to let the facts in, even when they don’t conform to our preconceptions. It counsels us to carry alternative hypotheses in our heads and see which best fit the facts. It urges on us a delicate balance between no-holds-barred openness to new ideas, however heretical, and the most rigorous skeptical scrutiny of everything — new ideas and established wisdom. This kind of thinking is also an essential tool for a democracy in an age of change.

I had become friendly with a group of people who occasionally smoked cannabis, irregularly, but with evident pleasure. Initially I was unwilling to partake, but the apparent euphoria that cannabis produced and the fact that there was no physiological addiction to the plant eventually persuaded me to try. My initial experiences were entirely disappointing; there was no effect at all, and I began to entertain a variety of hypotheses about cannabis being a placebo which worked by expectation and hyperventilation rather than by chemistry. After about five or six unsuccessful attempts, however, it happened.