We make our purpose. - Carl Sagan

You'd be surprised how rarely something like that happens. In the long run, the aggressive civilizations destroy themselves, almost always. It's their nature. They can't help it. In such a case, our job would be to leave them alone. To make sure that no one bothers them. To let them work out their destiny.

Because science carries us toward an understanding of how the world is, rather than how we would wish it to be, its findings may not in all cases be immediately comprehensible or satisfying. It may take a little work to restructure our mindsets. Some of science is very simple. When it gets complicated, that’s usually because the world is complicated — or because we’re complicated.

For thousands of years humans were oppressed — as some of us still are — by the notion that the universe is a marionette whose strings are pulled by a god or gods, unseen and inscrutable. Then, 2,500 years ago, there was a glorious awakening in Ionia: on Samos and the other nearby Greek colonies that grew up among the islands and inlets of the busy eastern Aegean Sea. Suddenly there were people who believed that everything was made of atoms; that human beings and other animals had sprung from simpler forms; that diseases were not caused by demons or the gods; that the Earth was only a planet going around the Sun. And that the stars were very far away.