Cosmos: A Personal Voyage

By Carl Sagan (1980)

The ash of stellar alchemy was now emerging into consciousness. At an ever-accelerating pace, it invented writing, cities, art and science, and sent spaceships to the planets and the stars. These are some of the things that hydrogen atoms do, given fifteen billion years of cosmic evolution.

My Notes

Books are like seeds. They can lie dormant for centuries and then flower in the most unpromising soil.

No civilization can possibly survive to an interstellar spacefaring phase unless it limits its numbers. Any society with a marked population explosion will be forced to devote all its energies and technological skills to feeding and caring for the population on its home planet.

Anaximenes (c. 586 – c. 526 BCE),

To what purpose should I trouble myself in searching out the secrets of the stars, having death or slavery continually before my eyes?

Each second a thousand suns are born.

It is not perfect. It can be misused. It is only a tool. But it is by far the best tool we have, self-correcting, ongoing, applicable to everything. It has two rules. First: there are no sacred truths; all assumptions must be critically examined; arguments from authority are worthless. Second: whatever is inconsistent with the facts must be discarded or revised. We must understand the Cosmos as it is and not confuse how it is with how we wish it to be.