---
title: "The Demon-Haunted World"
chunk: 1/3
source: "https://en.wikipedia.org/wiki/The_Demon-Haunted_World"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T03:31:38.450954+00:00"
instance: "kb-cron"
---

The Demon-Haunted World: Science as a Candle in the Dark is a 1995 book by the astronomer and science communicator Carl Sagan. (Four of the 25 chapters were written with Ann Druyan.) In it, Sagan aims to explain the scientific method to laypeople and to encourage people to learn critical and skeptical thinking. He explains methods to help distinguish between ideas that are considered valid science and those that can be considered pseudoscience. Sagan states that when new ideas are offered for consideration, they should be tested by means of skeptical thinking and should stand up to rigorous questioning.

== Themes ==
Sagan explains that science is not just a body of knowledge, but is a way of thinking. Sagan shows how scientific thinking is both imaginative and disciplined, bringing humans to an understanding of how the universe is, rather than how they wish to perceive it. He says that science works much better than any other system because it has a "built-in error-correcting machine". Superstition and pseudoscience get in the way of the ability of many laypersons to appreciate the beauty and benefits of science. Skeptical thinking allows people to construct, understand, reason, and recognize valid and invalid arguments. Wherever possible, there must be independent validation of the concepts whose truth should be proved. He states that reason and logic would succeed once the truth was known. Conclusions emerge from premises, and the acceptability of the premises should not be discounted or accepted because of bias.

=== Dragon in my garage ===

As an example of skeptical thinking, Sagan offers a story concerning a fire-breathing dragon who lives in his garage. When he persuades a rational, open-minded visitor to meet the dragon, the visitor remarks that they are unable to see the creature. Sagan replies that he "neglected to mention that she's an invisible dragon". The visitor suggests spreading flour on the floor so that the creature's footprints might be seen, which Sagan says is a good idea, "but this dragon floats in the air". When the visitor considers using an infrared camera to view the creature's invisible fire, Sagan explains that her fire is heatless. He continues to counter every proposed physical test with a reason why the test will not work.
Sagan concludes by asking: "Now what's the difference between an invisible, incorporeal, floating dragon who spits heatless fire and no dragon at all? If there's no way to disprove my contention, no conceivable experiment that would count against it, what does it mean to say that my dragon exists? Your inability to invalidate my hypothesis is not at all the same thing as proving it true."
Continuing with concepts relevant to the 'dragon in my garage' story, Sagan writes about a patient of John Mack who claimed to have scars on her body which were from encounters with aliens. Sagan writes that if the patient is asked what her scars look like, she is unable to show them because, unfortunately, they are located in the private areas of her body.
 

=== Baloney detection kit ===
Sagan presents a set of tools for skeptical thinking that he calls the "baloney detection kit". Skeptical thinking consists both of constructing a reasoned argument and recognizing a fallacious or fraudulent one. In order to identify a fallacious argument, Sagan suggests employing such tools as independent confirmation of facts, debate, development of different hypotheses, quantification, the use of Occam's razor, and the possibility of falsification. Sagan's "baloney detection kit" also provides tools for detecting "the most common fallacies of logic and rhetoric", such as argument from authority and statistics of small numbers. Through these tools, Sagan argues the benefits of a critical mind and the self-correcting nature of science can take place.
Sagan provides nine tools as the first part of this kit.

There must be independent confirmation of the facts given when possible.
Encourage debate on the evidence from all points of view.
Realize that an argument from authority is not always reliable. Sagan supports this by telling us that "authorities" have made mistakes in the past and they will again in the future.
Consider more than one hypothesis. Sagan adds to this by telling us that we must think of the argument from all angles and think all the ways it can be explained or disproved. The hypothesis that then still hasn't been disproved has a much higher chance of being correct.
Try to avoid clinging obdurately to your own hypothesis and so become biased. Sagan tells us to compare our own hypothesis with others to see if we can find reasons to reject our own hypothesis.
Quantify. Sagan tells us that if whatever we are trying to explain has numerical value or quantitative data related to it, then we'll be much more able to compete against other hypotheses.
If there is a chain of argument, every link in that chain must be correct.
The use of Occam's razor, which says to choose the hypothesis that is simpler and requires the fewest assumptions.
Ask if a given hypothesis can be falsified. Sagan tells us that if a hypothesis cannot be tested or falsified then it is not worth considering.
Sagan suggests that with the use of this "baloney detection kit" it is easier to critically think and find the truth.

==== Logical fallacies ====
There is a second part to the kit. This consists of twenty logical fallacies that one must not commit when offering up a new claim.