The Demon-Haunted World: Science as a Candle in the Dark is a book by Carl Sagan intended to explain the scientific method to laypersons, and to encourage people to learn critical or skeptical thinking. It explains methods to help distinguish between ideas that are considered valid science, and ideas 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.




Sagan said if a new idea continues in existence after an examination of the propositions, it should then be acknowledged as a supposition. Skeptical thinking essentially is a means 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 believed that reason and logic would succeed once the truth is known. Conclusions emerging from a premise, and the acceptability of the premise should not be discounted or accepted because of bias.

Sagan presents a set of tools for skeptical thinking which 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 the employment of such tools as independent confirmation of facts, quantification and the use of Occam's razor. Sagan's "baloney detection kit" also provided tools for detecting "the most common fallacies of logic and rhetoric", such as argument from authority and statistics of small numbers.

Through these tools, the benefits of a critical mind and the self-correcting nature of science can take place. Sagan provides a skeptical analysis of several kinds of superstition, fraud, pseudoscience and religious beliefs, such as gods, witches, UFOs, ESP and faith healing.

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# "Science is more than a body of knowledge; it is a way of thinking. I have a foreboding of an America in my children's or grand children's time ... when awesome technological powers are in the hands of a very few, and no one representing the public interest can even grasp the issues; when the people have lost the ability to set their own agendas or knowledgeably question those in authority; when clutching our crystals and nervously consulting our horoscopes, our critical faculties in decline, unable to distinguish between what feels good and what's true, we slide, almost without noticing, back into superstitions and darkness."

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# "Is it fair to be suspicious of an entire profession because of a few bad apples? There are at least two important differences, it seems to me. First, no one doubts that science actually works, whatever mistaken and fraudulent claim may from time to time be offered. But whether there are *any* "miraculous" cures from faith-healing, beyond the body's own ability to cure itself, is very much at issue. Secondly, the expose' of fraud and error in science is made almost exclusively by science. But the exposure of fraud and error in faith-healing is almost never done by other faith-healers."
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"Carl Sagan's message will not be congenial to many in today's society.

An ethic of superstition and refusal to consider evidence as relevant is growing. Some profit from this state of affairs, and seek to foster it. Many others have absorbed part of that ethic. All the more reason to pick up Sagan's readable, enjoyable, compellingly-argued, and very human book."