Dr. Sagan’s other academic achievements included twenty-two honorary degrees and the Public Welfare Medal, the highest award of the National Academy of Sciences. One of his numerous books, “Cosmos”, which explained complex scientific concepts and corresponded to a TV series with the same title, became the most widely read science book ever published in the English language [1, 3]. His role as a science communicator wasn’t limited to his work as an author. The acclaimed television series “Cosmos” became the most widely watched series on American public television [2, 3] and held the record for ten years, until 1990.

Carl Sagan’s achievements are too numerous to name in a short article. His work on promoting science can also be appreciated in science fiction books such as “Contact” (and a film based thereupon).

In his book on rationality and skepticism, “The Demon-Haunted World: Science as a Candle in the Dark”, Carl Sagan discusses myths, pseudoscience, New Age thinking, etc., with reference to our increasingly technology-driven world. The author debunks various superstitious beliefs, such as psychic powers or witchcraft, and provides a clear conclusion on how dangerous it may be when societies wander off from the path of science and rationality and risk going back to wishful thinking and magical perception of the world. 

Chapter 10 of the book, entitled “The Dragon in my Garage”, starts off with an interesting example of how an unfalsifiable claim (one which cannot be proven false) is actually a weak one. The author does so by provoking the reader with the following statement: “A fire-breathing dragon lives in my garage.”

The readers are invited to ponder their reaction to such a claim. What follows is a series of tests which could be conducted to verify such an extraordinary claim. We ask the claimant to show us the dragon and he leads us to an empty garage where the dragon is nowhere to be seen. “It’s an invisible dragon,” says the author. We then want to spread flour on the floor to see the footprints of the mythical beast. “The dragon floats in the air,” is the response. Next, we propose using infra-red or thermal imaging to detect the dragon. Unfortunately, the beast is heatless, says the garage owner. It occurs to us to spray-paint the floating dragon and thus make it visible. To which follows the response that the dragon is actually incorporeal and the paint won’t stick to it.

The tests can be invented further, of course. However, the author warns us in advance that every single one will be countered with a “special explanation of why it won’t work.” This is when the conclusive question is delivered – “What’s the difference between an invisible, incorporeal, floating dragon who spits heatless fire and no dragon at all?” 

In other words, if there is no way to disprove a claim, if there is no experiment which could test a hypothesis, then how strong is the claim in the first place? If “an assertion is immune to disproof”, it is also reduced to belief and, consequently, irrationality.  For further reading on unfalsifiable claims, please see our previous article on “How do scientists learn new things about the world?”.

This series of articles couldn’t have had any other scientist as the focus of its first part. Carl Sagan’s contribution to popularizing scientific and rational thinking is unmatched, not only because his books and TV shows reached such a big audience, but also because he actively participated in changing the world for the better by advocating, for example, the reduction of nuclear arsenal or an active stance against global warming [5]. The dragon exemplifying unfalsifiable claims is just a sample of the skeptical approach presented in “The Demon-Haunted World”, and the curious reader will certainly want to explore the subject more.