The abundance of conspiracy theories is visible and their growing influence on political lives in numerous countries is evident. The Qanon cult, which suggests the existence of an international peadophile ring involving politicians and celebrities, is growing even outside the USA, while its political connection to President Donald Trump and possible implications for the US 2020 presidential elections are undeniable [1, 2]. In Poland, in a vote from 21.08.2020, the Council of Solina Municipality voted against the introduction of 5G technology [3]. Europe has witnessed numerous protests against the social and medical approaches to the SARS-CoV-2 pandemic, with high numbers of participants carrying virus denying slogans [4]. The protestors were, customarily, supported by right-wing and anti-vaccination movements [5].

The purpose of this article is not to ask why people believe in conspiracies or how many do. It is also not to convince conspiracy followers their claims are unfounded – this task proves to be rather unattainable considering human nature and the ever growing reluctance to admit erroneous thinking. The goal is rather to provide the reader with proper philosophical tools for identifying unfounded ideas. The simple notion discussed in this article is as follows: the burden of proof lies on the party proposing the claim.

The notion has been restated in numerous forms by numerous philosophers, scientists and authors, including Bertrand Russell, Carl Sagan, and Christopher Hitchens (for biographical information please see [6], [7], [8]). However, as it is pointed out by Damion Reinhardt, the principle can be found in writing as early as in 1704, while the Latin phrase of equivalent meaning (Quod gratis asseritur, gratis negatur – What is asserted gratuitously may be denied gratuitously [9]) was widely in use in the early 19th century [10].

In Bertrand Russell’s version it takes the shape of a teapot. Russell stated that if there was a small teapot orbiting the Sun between Earth and Mars, there would be no way of disproving it. It is therefore the person claiming the teapot really exists who should prove the claim.

Carl Sagan stated a similar notion with the aphorism “Extraordinary claims require extraordinary evidence,” which was popularized in his 1980 TV show “Cosmos” [11]. Later, it appeared in his book on scientific method and skeptical thinking, “The Demon-Haunted World. Science as a Candle in the Dark” [12]. Sagan employed the rule in his effort to show how a skeptical approach can be used to confront superstition, charlatanism and pseudoscience.

In the words of Christopher Hitchens, “What can be asserted without evidence can also be dismissed without evidence.” In other words, the burden of proof lies with the one who makes the claim. The phrase was greatly popularized by Hitchens through his active career as a public speaker and through the success of his book on religion [13], hence its own name – Hitchens’s razor.

The reader will notice that the above-mentioned names include well-known atheists and agnostics. This is due to the fact that, as with many philosophical principles and ways of scientific thinking, the Burden of proof can be easily and successfully applied to disprove any supernatural claims.

Needless to say, scientists apply the rule in their research on a daily basis. Any properly published scientific paper begins with a question or a thesis and then proceeds to presenting suitable evidence for or against the claim. It is a routinely applied aspect of scientific methodology. Similarly, the principle is, to various extent, also applied in law, where it is usually established that the burden of proof is on the claimant.

The principle can be just as efficiently applied to everyday life. In fact, it is knowingly and unknowingly applied by people every day. We can easily imagine a person claiming they can fly. Most people would then ask for a demonstration. If a boss hears an employee’s promise to outperform everyone else by 500%, they will probably want to know how this feat can be achieved before allocating resources to it. If an alchemist told us to invest in their efforts, we would also want to see a sample of their skills. Finally, if told that their spouse is cheating on them, most people would ask for proof of the condemnable deed.

Coming back to conspiracy theories, the application of the rule is identical. When confronted with a claim such as “the world is ruled by a species of reptilians”, a skeptic would simply ask for evidence. It is highly doubtful any proof exists for such a dictum, especially since there are no discovered living or dead bodies of such extraordinary organisms. What properly validated evidence is there for the harmfulness of 5G technology? What facts corroborate that polio or measles vaccines caused more harm than good, when the illnesses have been virtually eradicated? What proof supports the idea that the pandemic is a broadly organized catastrophe event controlled by a secretive ruling caste instead of a regular pandemic of a new disease?

Asking questions is an important step on the road to freedom from unfounded beliefs. Our modern world bombards us with new theories, shocking news, extraordinary ideas, unimaginable innovations and, last but not least, fake information. Unfortunately, much of the information is simply opinion and lacks any foundations in reality. In worse cases, the supposed news are products of failed deductive processes or propaganda. This labyrinth of data is not easy to navigate, but certain tools may help lead us to the clear skeptical path.