Francis Bacon’s 4 Idols of the Mind and How to Overcome Irrationality

Francis Bacon


The primary impediments to the advancement of knowledge in humanity generally and in yourself specifically are the universal biases Francis Bacon identified as idols of the mind. Learning to identify and overcome these idols is the key to overcoming your innate irrational tendencies. Idols of the tribe convince you there is more order in the world than there really is; idols of the cave assure you that your beliefs are more certain than they really are; idols of the market fool you with the ambiguities of language; and idols of the theater compel you to proportion your beliefs according to popularity rather than truth. Counter these idols by actively trying to disprove your beliefs, remaining skeptical of your most passionately-held beliefs, avoiding the trappings of language and thought-terminating cliches, and proportioning your beliefs to the evidence.


Francis Bacon, often referred to as the father of empiricism, was an English philosopher, scientist, and early proponent of the scientific method, arguing for the advancement of scientific knowledge based on inductive reasoning and careful observation.

In the preface to his 1620 masterwork, the Novum Organon, Bacon wrote:

“Those who have taken upon them to lay down the law of nature as a thing already searched out and understood, whether they have spoken in simple assurance or professional affectation, have therein done philosophy and the sciences great injury. For as they have been successful in inducing belief, so they have been effective in quenching and stopping inquiry; and have done more harm by spoiling and putting an end to other men’s efforts than good by their own.”

According to Bacon, those who claim to have infallible knowledge of the world inflict great harm upon humanity by stifling curiosity, blocking further inquiry, and preying on natural human gullibility and the desire for easy or comforting explanations.

The goal of the Novum Organon, then, was to set humanity upon a different course. Bacon wrote, “I open and lay out a new and certain path for the mind to proceed in, starting directly from the simple sensuous perception.”

Bacon’s vision was an early form of the scientific method, based on careful observation, rational calculation, and checks against innate irrationality, which was (and is) the primary obstacle to the advancement of knowledge. Bacon, anticipating modern cognitive psychology by several centuries, identified four universal biases built into the human psyche. Bacon labeled these biases idols of the mind:

“Four species of idols beset the human mind, to which (for distinction’s sake) we have assigned names, calling the first Idols of the Tribe, the second Idols of the Cave, the third Idols of the Market, the fourth Idols of the Theatre.”

Bacon’s intention was to create a scientific method that could overcome these biases, setting humanity on the path of progress. But for our purposes, we can think of the idols as personal traps, or systematic generators of error and bias. To conquer these idols is to conquer our own irrationality, to open the door to new experiences and perspectives and to get closer to the truth. Bacon knew that before one can truly learn, one must clear away the impediments to learning.

Let’s take a closer look at the four idols and how they can be overcome.

Idols of the Tribe

“The idols of the tribe are inherent in human nature and the very tribe or race of man; for man’s sense is falsely asserted to be the standard of things; on the contrary, all the perceptions both of the senses and the mind bear reference to man and not to the universe, and the human mind resembles those uneven mirrors which impart their own properties to different objects, from which rays are emitted and distort and disfigure them.” – Francis Bacon

Idols of the tribe are the first group of biases identified by Bacon. These idols are universal and innate, and, unlike the other three, do not have to be learned. Idols of the tribe are based on (at least) four psychological tendencies:

  1. Anthropomorphism – the imposing of human characteristics on non-human things, as when one hears voices in the wind or attributes malicious intent to a computer.
  2. Psychological projection – attributing one’s own qualities, interests, or perspectives onto someone or something else.
  3. Hyperactive agency detection – the tendency to attribute agency and intention to any event, as when someone assumes that the rustling in the bush is the result of someone of something’s presence, rather than the wind. (Some suggest that this evolutionary adaptation, conducive to survival, is the origin of religious belief, or the finding of agency in all things.)
  4. Hyperactive pattern recognition – the tendency to find patterns in random data, as is found in most outlandish conspiracy theories.

What all four tendencies have in common is the inclination to delusion—to read something into a situation that isn’t there. This can lead to a host of faulty beliefs, including the perception of faces in clouds or in NASA’s photos of Mars, the belief in ghosts and spirits, or the belief that the moon landing was faked, which proponents “confirm” by searching for “evidence” that corroborates the belief while disregarding the improbability of a cover-up on that scale.

As Bacon wrote, “The human understanding is of its own nature prone to suppose the existence of more order and regularity in the world than it finds.”

And once someone adopts a belief, they will actively seek to confirm this belief by searching for confirmatory evidence and ignoring contrary evidence (known as the confirmation bias). As Bacon wrote, “The human understanding when it has once adopted an opinion (either as being the received opinion or as being agreeable to itself) draws all things else to support and agree with it.”

How to overcome idols of the tribe: To counter these tendencies, actively seek to refute your own theories and search for contrary evidence. Rather than succumbing to the confirmation bias, find the strongest argument against your position and seriously consider the prospect that you are wrong. This is the spirit of science, where any given theory is made stronger through attempts to refute it.

Idols of the Cave

“The idols of the cave are those of each individual; for everybody (in addition to the errors common to the race of man) has his own individual den or cavern, which intercepts and corrupts the light of nature, either from his own peculiar and singular disposition, or from his education and intercourse with others, or from his reading, and the authority acquired by those whom he reverences and admires, or from the different impressions produced on the mind, as it happens to be preoccupied and predisposed…so that the spirit of man (according to its several dispositions), is variable, confused, and as it were actuated by chance; and Heraclitus said well that men search for knowledge in lesser worlds, and not in the greater or common world.”

The key idea here is that the mind—due to accidents of birth and environment—will latch onto certain ideas, events, people, or historical eras and then interpret these things as innately superior. People tend to view the world through the lens of their own experiences and interests, which can lead to narrow-mindedness and dogma.

Bacon identified two problems that result from this: 1) political extremism, and 2) prejudice and racism.

In terms of politics, Bacon wrote, “There are found some minds given to an extreme admiration of antiquity, others to an extreme love and appetite for novelty; but few so duly tempered that they can hold the mean, neither carping at what has been well laid down by the ancients, nor despising what is well introduced by the moderns.”

People tend to gravitate to the extremes of the political spectrum—with radical conservatives occupying one end and radical liberals occupying the other—and what gets lost in the conversation is how to navigate the middle path of responsible reform. Extremists and fundamentalists tend to set the agenda to the detriment of everyone else.

Racism, similarly, is a radical position, which attributes to every member of a group the perceived averages of that group. So, for example, a group may be perceived, based on someone’s limited experience, as having, on average, a lower IQ (even though this is likely based on a small sample size). That person would then erroneously attribute the lower IQ to every member of that group.

But, regardless of what the real “average” is, individual variation among any group is large, so it is clearly a fallacy to judge an individual by the averages of their group. This recognition is the basis for the idea that all people should have equal protection and opportunity under the law, and that all should be judged by the content of their character and by their achievements rather than on superficial group differences.

How to overcome idols of the cave: The more passionately you hold a belief, the more suspicious you should be of that belief. As Bacon wrote, “generally let every student of nature take this as a rule: that whatever his mind seizes and dwells upon with peculiar satisfaction is to be held in suspicion, and that so much the more care is to be taken in dealing with such questions to keep the understanding even and clear.” Realize that you are most susceptible to confirmation bias the more emotionally invested you are in a particular belief. It is in precisely these areas that you should seek out disconfirming evidence and the opposing arguments.

Idols of the Market

“There are also idols formed by the reciprocal intercourse and society of man with man, which we call idols of the market, from the commerce and association of men with each other; for men converse by means of language, but words are formed at the will of the generality, and there arises from a bad and unapt formation of words a wonderful obstruction to the mind. Nor can the definitions and explanations with which learned men are wont to guard and protect themselves in some instances afford a complete remedy—words still manifestly force the understanding, throw everything into confusion, and lead mankind into vain and innumerable controversies and fallacies.”

Bacon understood the difficulties with language long before the advent of modern linguistics and the philosophy of language. Bacon identified two problems in particular: 1) names for things which do not exist, and 2) names that are confused and ill-defined.

First, language can be used in reference to both things that exist and things that only exist within the mind. The mind has the unique combinatorial capacity to take existing things in the world and to combine them in novel ways or to extend their properties.

As an example, mythological creatures, which obviously do not exist in the world, are composed of the parts taken from animals that do exist in the world. In a similar manner, the ancient Greek pantheon of gods, while not existing in the real world, are composed of human characteristics, found in the real world, taken to extremes. (Which raises the question: Is the monotheistic God of the Abrahamic religions simply a maximal extension of the observed power, goodness, and knowledge found in real people?)

Confusion results when we forget the distinction between what is real and what is simply the word or name assigned to an abstract entity that represents a mental reconfiguration of things that actually exist in the world. As Bacon wrote, “Man, being the servant and interpreter of Nature, can do and understand so much and so much only as he has observed in fact or in thought of the course of nature. Beyond this he neither knows anything nor can do anything.” This anticipates what Wittgenstein would later say: “Whereof one cannot speak, thereof one must be silent.”

The second problem is in reference to ill-defined and confused words, phrases, or labels, of which there are countless examples. One example is the use of thought-terminating cliches, used extensively in politics to condense complex problems into brief and reductive phrases that discourage critical thinking, reflection, and elaboration.

For example, the response “that’s just a liberal/conservative/libertarian argument” is used to discredit the idea out of hand, without needing to assess the argument or proposal itself. Regardless of your political affiliation, it is possible for the other side to be right in some respect or to propose a good policy from time to time, but modern political discourse has descended into a series of ad hominem attacks and the utterance of thought-terminating cliches that prevent any such productive dialogue—the exact problem Bacon identified centuries ago.

How to overcome idols of the market: Do not be fooled by language; understand that being able to name something does not make it real. Learn to identify thought-terminating cliches and simplistic labels and pledge to never utter them again in debate. Pay attention to your language and never reduce complex issues into sound-bites, and always give the opposing side of an argument a fair hearing without prejudgement or labeling.

Idols of the Theatre

“Lastly, there are idols which have crept into men’s minds from the various dogmas of peculiar systems of philosophy, and also from the perverted rules of demonstration, and these we denominate idols of the theatre: for we regard all the systems of philosophy hitherto received or imagined, as so many plays brought out and performed, creating fictitious and theatrical worlds…Nor, again, do we allude merely to general systems, but also to many elements and axioms of sciences which have become inveterate by tradition, implicit credence, and neglect.”

Here Bacon was targeting all previous philosophical and religious systems, as these, particularly Aristotelianism and Christianity, stood in the way of his new scientific method and future progress. He likened these systems to theatrical plays (much like Yuval Harari’s “imagined realities”), writing, “because in my judgment all the received systems are but so many stage plays, representing worlds of their own creation after an unreal and scenic fashion.”

These idols are particularly dangerous because 1) they tend to be emotionally appealing and dramatic and 2) they have the appearance of validity based on the number of people that believe in the story and the length of time the story has survived.

There are three relevant fallacies at work here:

  1. Appeal to tradition – believing that something is beneficial or true simply because it has traditionally been thought to be true. (The study of the history of medicine should disabuse you of this fallacy.)
  2. Appeal to popularity – believing that because everyone else is doing something that it is the right thing to do. (See the history of slavery and any number of popular delusions.)
  3. Wishful thinking – taking the wish for something to be true as evidence for it being true. (Example: I want to live forever, therefore I believe in an afterlife.)

The fact that something is widely believed does not make it true. As one example, consider that globally there are 2.4 billion Christians and 1.5 billion Muslims. Since these religions are mutually exclusive, it has to be the case that at least 1.5 or 2.4 billion people are mistaken, and possibly all 3.9 billion. These are astronomical numbers that demonstrate that people believe in things for all kinds of reasons other than for their truth value.

How to overcome idols of the theatre: Be wary of holding a belief primarily because many other people also hold the same belief. History is filled with examples of systems of philosophy, religion, and science that were widely held for long periods of time only to be later refuted and abandoned. Consider that some of your beliefs will likely receive a similar fate in the future. Question everything, and proportion your beliefs to the evidence, not to popularity.


Further Reading

Here are some of the best books on biases and fallacies for additional reading:

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