In chapter 10 of The Demon-Haunted World Carl Sagan talks about invisible dragons. Suppose a friend told you there was a dragon living in his garage. When you stop by to check it out, you learn that it is not only invisible, but it floats in the air, spouts invisible and heatless flames, and has no physical body. It is totally non-detectable, yet your friend assures you he is certain it exists. You would doubtless conclude that in the absence of any evidence whatsoever for its reality that this dragon exists only in your friend’s mind. Sagan talks about other possibilities – what if many otherwise reasonable people also claim to be hosting invisible dragons? What if there is some sort of evidence, a careless claw print or a burnt finger from momentarily hot dragon breath?
Of course the invisible dragon is just a silly example of a belief held in the absence of evidence (though I’m sure that somewhere out there you’ll find at least a few invisible dragon believers). Sagan discusses under what circumstances you might accept your friend’s contention, and how you might otherwise interpret the situation, but he is never harsh or cruel in talking about such people. The same is true of the many real-life examples of pseudoscience and myths, and even of hoaxes and of what I would call pure bunk. Sagan applies the warm light of reason, while recognizing that for many reasons, people often do wish for and believe in things for which there is no objective evidence. He does not ridicule believers, but he argues compellingly for the greater utility of the evidence-based approach we have come to call science (the book’s subtitle is “science as a candle in the dark”).
Carl Sagan died eleven years ago today. He was a scientist, an atheist, a humanist, a fine writer, and a great popularizer of science. Although some fellow scientists may have dismissed him as a relative light weight, as a mere popularizer (in spite of significant research results and many scientific publications throughout his career), I believe he was one of the most important scientists of the twentieth century because he was one of the few who made an effort to communicate science to everyone, and to do it so well and so entertainingly. The universe is tough to understand, and technology can be even harder, but we need to try to understand what is really going on – every one of us. We live in a world of physical laws, surrounded by a growing array of technology and its many side effects. We don’t all need to be scientists, but we all need to be able to evaluate evidence to form opinions and make all sorts of decisions that affect our own lives and contribute their effects to the world around us, to separate the pseudo from the science.
Sagan himself was not totally immune from belief and wishful thinking – for example, he wanted very much to believe that the universe is teeming with life. Maybe it is – but the evidence is just not in yet. We are still looking for it, with rovers rolling around on Mars and with arrays of radio antennas listening for signals from the stars. I’m sure Sagan would be happy about all that, anxious to hear some good news, to see real evidence of life beyond the Earth. But Carl Sagan was satisfied with the universe as it really was and is, with the natural richness of its physics and biology, and with the human-made richness of our cultures, societies, and relationships. Within those realms I know I too can find all the spirituality I will ever need, and I’m grateful that Carl Sagan was here to help me (and so many others) to see and appreciate the wonder of all that really is.
This blog post is one of many written today in memory of Carl Sagan on the eleventh anniversary of his death. Many of these posts are really wonderful and well worth reading, including a warm message from Carl Sagan's wife, Ann Druyan.