The cuckoo, as is well known, is a devious, shifty, and indolent bird that lays its eggs in the nests of other birds, while pushing out of the nest the eggs laid by the parents, so that they, poor, unsuspecting birds, raise the cuckoo’s offspring as if they were their own, which then continue the cycle of treacherous exploitation. For its behaviour, the cuckoo has become a symbol of deceit, such as, in some countries, of marital infidelity, as is expressed by the English word “cuckold” and the phrase “to be cuckolded,” both of which refer to a man whose wife has had sexual relations with another man.
The phrase, “Cloud Cuckoo Land,” was used by the ancient Greek dramatist Aristophanes in his play, The Birds, to refer to an unrealistic, because unachievable, conception or state of the world – what today we would call a utopia. In this essay, I wish to use the phrase in a slightly difference sense. The metaphor I want to convey by evoking the cuckoo’s behaviour is the image of falsehood displacing truth in the brains of those individuals who believe in a false idea or dogma. Like the offspring of the cuckoo, these false beliefs can beget other false ideas and practices, and, at least for a time, infect others like a virus, thus ensnaring a greater and greater number of people in their web of plausible falsehood and deceit.
To begin, let us consider the following questions: Where do these false ideas come from? Why, at least for a time, are some of them widely adopted? How can they be distinguished from true ideas? What can be done to discredit or disprove those false ideas that are presently widely accepted? And, in the future, how can we prevent such ideas from gaining widespread credulity, allegiance, and fervent support?
Without doubt, the ancient Greek philosopher Aristotle was one of the most intelligent persons ever to have lived. And yet, he uttered many falsehoods when discoursing on the natural world, for the simple reason that he never bothered to verify or test his beliefs. He believed, as many people still do today, that the mere fact that an idea seemed sensible to him, or that an argument was logically sound, was sufficient for it to be true. This is a very common mistake. For example, he believed it was impossible that the Earth rotates like a giant spinning globe because, he argued, in that case the air would blow continually, as it would during a violent tempest, from the Earth’s constant rotation. Although this idea seems sensible enough, it happens to be wrong. Aristotle’s mistake was in supposing that the Earth’s atmosphere would remain stationary rather than rotate along with it, like everything else on the Earth’s surface.
The many errors made by Aristotle, as well as by many other intelligent individuals who have believed things that are false, show that, by itself, intelligence is no guarantee of truth, since even highly intelligent persons are capable of believing things that later generations find ridiculous or hard to believe.
Human beings are imitative creatures. But there is no guarantee that the things we imitate will be beneficial or good. In the realm of truth and falsehood, this means that people can very easily imitate falsehoods by repeating them, and thus come to believe things that are not true. Some generally accepted falsehoods have done or can do a great deal of harm. Examples are communism, free-market capitalism, Montesquieu’s theory of the separation of powers, Plato’s theory of education, and the practice of bloodletting, which arose from the four humours theory of the human body.
In an ideal world, we would only do things that are beneficial or good and only believe things that are true. But obviously, in the imperfect world we live in, this does not always happen. How, then, can we distinguish truth from falsehood? Considering how much harm has been done by the pernicious influence of false ideas and theories, it is extremely important to find an answer to this question.
I do not know what sorts of conceptions other animals and organisms have – whether, like human beings, they can imagine things about the world that don’t exist, or whether their conceptions are strictly limited to their perceptions. The ability to conceive things that differ from our perceptions is indeed a source of new ideas, but it is also a very common source of error, for the great majority of these new ideas are false, silly, impractical, unrealistic, or just plain stupid. This ability, which is perhaps unique to – or if this is not true, then most highly developed in – human beings, is both one of our main strengths and weaknesses, for although it has enabled us to alter the environment to an extent that is simply not possible for other organisms, at the same time, it has been the source of innumerable errors that have done a great deal of harm to our species.
It is this ability that has led to the development of art in all its diverse and wondrous forms, fueled technology with the countless inventions and innovations that have transformed the world while radically changing the way we live, and provided scientists with the insights that have allowed their disciplines to develop and flourish. But along with these beneficial consequences, this ability has also been the source of countless errors.
To the extent that they portray a reality that differs from the reality of real life, movies are another source of false ideas about the world. For example, besides science fiction, the false belief that human beings will one day colonize and inhabit other planets arises primarily from movies. And the pseudo-realities which are depicted in movies but don’t exist in the real world can encourage behaviours or beliefs that are artificial, foolish, uncommon, or invented.
Human beings have other tendencies. The tendency to generalize is not unique to humans, since the ability to recognize food, habitats, and potential mates, as well as enemies, predators, and other dangers is essential to the survival of all perceiving organisms. In humans, the systematic tendency to generalize gave rise to philosophy, which has had a decidedly mixed effect on our species’ development. Another important human trait that is less global is the desire for completeness. When these three tendencies unite – the ability to give birth to new ideas, the tendency to generalize, and the desire for completeness – they beget comprehensive systems of the world that are variously called philosophy, religion, or science.
The invention of writing and, later, of printing allowed for the wider dissemination, both through space and time, of novel ideas and practices. It also allowed these ideas to become more complex, developed, and complete. For instance, it is hard to imagine that the highly complex, precise, and intricate edifice of scientific knowledge could have been erected and preserved – without loss, corruption, or degeneration – strictly through an oral tradition without the aid of writing and printing.
With the gradual development of more rapid means of transportation and communication, new ideas were able to reach an ever increasing number of individuals. Formerly, the imitation or development of a norm was limited to those who grew up observing it or lived in close proximity to those who practised it, or heard someone like an elder recount aspects of the norm. But after the inventions of writing and printing, these spatial and temporal limitations were transcended. For example, from assiduously reading their writings, many individuals and societies have been influenced by the ideas, beliefs, and practices of a few ancient Greeks who lived more than two thousand years ago. In the case of science, in any given discipline, there are human worker bees living in different parts of the world who patiently and collectively gather the scientific nectar, in the form of precise, detailed observations, that is then transformed, whether by themselves or others, into the honey of scientific truth.
It is generally recognized that, at least in some branches of science, their practitioners have been singularly successful in performing the task of sifting truth from falsehood – in separating the useless chaff from the nourishing grain of truth. Thus, it behooves us to examine the manner in which science operates to see what we can learn.
The method that was developed by scientists is to test theories, ideas, and beliefs through experiment and observation in order to confirm or falsify them. In other words, it is not enough simply to formulate a logical, rational, or convincing argument in support of a position for it to be true, for our conception of reality must always be compared to reality, which is the ultimate arbiter of truth and falsehood. Otherwise, our conceptions are nothing more than shiny intellectual baubles that, however dazzling in their appeal, completeness, consistency, or abstract beauty, are useless for practical purposes, and, moreover, have the potential to do harm, and sometimes great harm, if they guide or influence people’s actions. Similarly, there are many useful physical tools, such as knives, axes, hammers, chainsaws, blow torches, furnaces, and motors, that, when they are improperly used, can cause considerable harm, including injury and death.
In one’s personal life, one can develop the habit of continually checking one’s ideas and beliefs, as well as the ideas and beliefs proposed by others, against the store of one’s experiences, and try to do so as objectively as possible. This means, depending on one’s inclinations, not simply recalling only those experiences which confirm, support, and seem to verify a given belief, but also those experiences which contradict and falsify one’s cherished beliefs. It is also necessary to enlarge one’s store of experiences, both directly and indirectly, such as by reading accurate and reliable books written by other people, and developing the habit of comparing general ideas or theories with particular examples to see if they are true or not.
The father of American physicist Richard Feynman was a remarkable man. Before the birth of his first child, he declared to his wife that if the child was a boy, he wanted his son to become a scientist. Although he himself never went to university, and he had difficulty understanding some of the concepts and theories of modern physics, he nevertheless had a rare understanding of the origins of truth and falsehood about the world. He inculcated in his son the great importance of observing the way things really are, rather than simply repeating what other people say, or believing what others have written in books, which is an all-too common shortcoming, especially among those who have spent many years in school, during which time they may inadvertently study and memorize the mistakes and falsehoods that have been made, or believed in, by others.
We had the Encyclopaedia Britannica at home. When I was a small boy he used to sit me on his lap and read to me from the Britannica. We would be reading, say, about dinosaurs. It would be talking about the Tyrannosaurus rex, and it would say something like, “This dinosaur is twenty-five feet high and its head is six feet across.”
My father would stop reading and say, “Now, let’s see what that means. That would mean that if he stood in our front yard, he would be tall enough to put his head through our window up here.” (We were on the second floor.) “But his head would be too wide to fit in the window.” Everything he read to me he would translate as best he could into some reality.
There follows a lengthy description about how Feynman’s father taught him to observe the behaviour of birds instead of simply repeating things about them, as most other parents would have done, such as their name in different languages, or their scientific Latin name. His father emphasized that these are simply human conventions, and therefore facts about human beings in different parts of the world, rather than facts about the birds themselves. In the following excerpt, we can see the effect that these teachings had on his son’s behaviour when he was older.
I had a scheme, which I still use today when somebody is explaining something that I’m trying to understand. I keep making up examples. For instance, the mathematicians would come in with a terrific theorem, and they’re all excited. As they’re telling me the conditions of the theorem, I construct something which fits all the conditions. You know, you have a set (one ball)—disjoint (two balls). Then the balls turn colors, grow hairs, or whatever, in my head as they put more conditions on. Finally they state the theorem, which is some dumb thing about the ball which isn’t true for my hairy green ball thing, so I say, “False!”
I myself have benefitted from the elder Feynman’s teachings about the importance of grounding one’s beliefs and conceptions in reality, and ignoring or not being swayed by the things that other people say and write, especially when they are wrong, even in cases where they are said by those who are considered to be authorities on a subject.
In general, we should be wary or skeptical of ideas that have not yet been tested against reality, no matter how convincing they may seem. They should be labelled as “Untested New Idea” or “Untested Old Idea.” In other words, people should be made aware that this or that idea has yet to be tested against or compared with reality, and therefore it should not be accepted uncritically, as unfortunately so often happens. We should not accept as true any proposition that, no matter how convincing or self-evident it may seem, has yet to pass through the furnace of reality in order to see whether it is made of pure truth or is merely a cunning counterfeit made of wax that has only the semblance of truth and will quickly melt, rather than being made of the hard, refined metal of tempered steel. Generally speaking, the fact that an idea is new is a reason for disbelieving it, since the great majority of new ideas turn out to be wrong, just as a person’s youth or physical immaturity is generally a reason for supposing that one is ignorant of many things and is not qualified to perform most skilled occupations. For ideas, like people, must pass through the stern trial of experience in order to arrive at the acquired distinction of maturity and competence, in the case of people, or truth, in the case of ideas.
In addition to testing our beliefs and theories continually against reality, we must also be aware of our preferences, which result from admiration, and our dislikes or prejudices, which result from contempt; for when these are strong, they can trick us into believing things that are false, or make us adamantly deny true statements, while we stubbornly cling to our false ideas, beliefs, or theories. We must constantly be aware of the distorting effects of admiration and contempt in determining and constraining our beliefs – that contempt can blind us to or make us obstinately deny facts or evidence that contradict our cherished beliefs, while admiration can make us too readily accept an idea or theory that is wrong or has yet to be proven, while seeing only those facts which seem to support it.
We should suspend our judgment and realize that, contrary to what the philosophers claimed, mere reason or logical argument cannot settle matters of truth or falsehood about things in the real world. We should always remember that even a man as wise and intelligent as Aristotle believed many things that were not true, for the simple reason that he never bothered to verify his beliefs about reality.
The philosopher René Descartes believed he had discovered an infallible method for sifting truth from falsehood. In his widely read and influential work, Meditations on First Philosophy, he advanced the idea that, in order for an idea to be true, it is only necessary that it be clear and distinct. By starting with a small number of clear and distinct ideas, such as one’s conception of the idea of God, a perfect and infinite being that created the Universe, he believed that we could deduce the nature of reality through the judicious use of reason. But his method does not work, which is shown by the fact that philosophers have been especially prone to believing and promulgating false statements and theories.
Descartes’ method of discovering the truth – by reasoning from basic premises and accepting only those ideas that are clear and distinct, and rejecting all ideas that fail to meet these simple criteria, but without testing these ideas against the real world – in fact has contributed to the widespread acceptance of many ideas that originated from Cloud Cuckoo Land. For one can just as easily have a clear and distinct conception of an idea that is completely false as of an idea that is true. Examples are that the moon is made of cheese, one day human beings will colonize other planets, the Earth lies at the centre of the Universe, tomatoes are poisonous, the Earth is flat, economists know what they are talking about and therefore we should trust them, psychoanalysis correctly explains human behaviour and it is able to cure people’s emotional problems, human beings are the acme of evolution on Earth, bleeding is a beneficial medical practice, God does not exist, science and technology will save humanity from its own excesses, we will never become extinct, human beings are wise, and all things are made up only of the four elements earth, air, fire, and water. Another example is Montesquieu’s theory of the separation of powers, which is both clear and distinct and, moreover, is quite plausible – but it happens to be false, a truth that most Americans have yet to recognize, due to their adulation of those fallible and imperfect individuals whom they honour by the august name of the Founding Fathers of their Great and Glorious Republic. We have all had the experience of clearly and distinctly remembering a certain fact or memory which, however, we later realize is completely wrong, distorted, or never happened. The simplicity, clarity, and distinctness of many false ideas and theories have led to their being widely accepted in spite of their falsehood.
In addition, some ideas that are true are counterintuitive or not at all easily understood. Some examples are Maxwell’s Theory of Electromagnetism, the theory of quantum mechanics, and Einstein’s Special and General Theories of Relativity. But counterintuitive and contrary to common sense and experience as they are, Einstein’s two Theories of Relativity have been accepted as true because parts of them have been successfully tested against reality.
By boastfully crowing that he had discovered an infallible method for determining the truth, René Descartes was one of the main culprits of the dissemination of countless ideas that have originated from Cloud Cuckoo Land. In reality, his vaunted method, which has been celebrated for centuries by the philosophical progeny of the Cartesian Cuckoo as a landmark intellectual achievement, is simply one of the many ideas that have come to us from Cloud Cuckoo Land, since it has encouraged rather than checked and diminished the proliferation of false ideas. As we have seen, his criterion of “clarity and distinctness” is neither a necessary nor a sufficient condition for something to be true.
The mistake made by Descartes was extending the application of reasoning beyond its legitimate domain, which consists of mathematics, logic, and a few of the sciences, to include all of human knowledge, including those disciplines where the sovereignty of pure reason must give way to the wisdom of accumulated observations and experience, which is simply another way of saying “the way the world really is,” and not the way that we extremely fallible and error-prone humans think or believe it is, or want it to be.
Even in physics, the most mathematical of all the sciences, it is still necessary to test conclusions against reality, an important fact that was understood by Albert Einstein.
As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality.
Considering how many blunders have been made by the advocates and practitioners of reason, we can conclude that, outside the domains of logic and mathematics, the use of reason, without any other aids or standards, is, more often than not, an infallible way to arrive at false beliefs about the world rather than the truth. In other words, reason alone, uncorrected by experience, is no guarantee of truth. For reason unaided by experience is like a blind man who confidently sets forth on a long journey but is unaware of the abyss of falsehood that gapes treacherously on all sides, an abyss into which a great many unsuspecting individuals have fallen throughout the ages. And this is not a truth that can be arrived at by the sole use of our reason, for it can only be discovered by experience, from the litany of innumerable false ideas that once held, or continue to hold, sway over a significant portion of humanity.
Euclid’s Elements has dazzled philosophers, scientists, and other readers throughout the ages with its deduction of a plethora of truths from a few simple and self-evident premises. However, the model of mathematical deduction has little or no validity in the realm of human affairs. It was the imitation of this model that is valid only in certain limited disciplines that has begotten such a vast quantity of errors. Numberless are the philosophers, thinkers, economists, and other writers who have assumed that they need only reason correctly about the natural or human world in order to understand it and deduce various truths about it. More often than not, their reasonings, when they have not been grounded in and corrected by experience, have led them down the treacherous abyss of falsehood and error.
Generally speaking, human beings, even the most intelligent among them, are prone to error when they use the sole criterion of reason as a guide to determine the truth in human affairs. We must especially beware of systems that claim to be complete, comprehensive, cohesive, and logically consistent. These systems appeal to readers precisely because of these impressive characteristics; but it is hardly likely that a system created by the fertile imagination of one or even several human beings will correspond to reality. We must continually remind ourselves that the inventive or imaginative faculty – the human generator of new ideas – is often deceptive and is frequently the source of falsehood rather than truth. Although such systems, when they confine themselves to subjects like mathematics, logic, and physics, can be valid, they are a principle source of error when they stray beyond these narrow limits. Some notable examples are the ideal society presented in Plato’s Republic, communism, psychoanalysis, Ayn Rand’s Objectivism, and the economic philosophy known as laissez-faire or free-market capitalism.
Many people, including those who go by the name of social scientists, have been misled by the example of science and mathematics. In these disciplines, the use of reason, meaning the rigorous application of logical rules to deduce conclusions from premises or previously verified statements or theories can lead to new conclusions that are also true. But this method of discovering the truth is much less valid, or not valid at all, in the social sciences.
It was the spectacular success of Rationalism or reason, when applied to mathematics, and to sciences like physics and chemistry, that has led many others to imitate this method by mistakenly applying it to other disciplines, since success ever breedeth imitation, in particular to the study of human behaviour, which has led to so much error, confusion, and, in some cases, grief. In regard to false ideas that presently hold sway over a large number of people, the only way to disabuse these misguided individuals is by metaphorically killing the cuckoo and destroying its eggs, either by showing that the idea is wrong, or by ridiculing, criticizing, and destroying the pernicious reputation of the idea’s cuckolding progenitor, so that the devious and malicious intellectual cuckoo will no longer be able to perpetuate its deceit and falsehood among the unsuspecting persons who nurture and raise its foul brood.
Until now, in this discussion of the sources of human error, we have been skirting, without having explicitly mentioned, the ancient controversy between Rationalism and Empiricism, the first of which championed reason as the infallible guide to arriving at the truth, and the second of which championed experience. We can now see that the great historical dispute between these two rival philosophical schools was spurious because they are valid in, and applicable to, different areas of human knowledge. In mathematics, logic, and sciences like physics and chemistry, the belief in Rationalism did indeed enable its practitioners to discover new truths about the world. But in social sciences like economics, psychology, and sociology, the imitation of this model has probably engendered more falsehood and confusion than truth. Instead, these disciplines must adopt the method of Empiricism, which asserts that truth is to be discovered by the observation of reality, supplemented, whenever possible, by experiment. Of course, this does not mean that reason has no role to play in these disciplines, but it must cede the primary place which it occupies in logic and mathematics to a different sovereign, namely, experience.
We can now at last cut the Gordian knot of Western philosophy by resolving the dispute between Rationalism and Empiricism. The mistake that was made by the adherents of these two schools was to assume that only one of these competing philosophies could be true. It was the assumption of universality that has misled philosophers throughout the ages to suppose that either Rationalism or Empiricism must be true – but not both – when the truth is that both of them are true, but in different domains of human knowledge. In doing so, they betrayed their philosophic origin by assuming that, for a philosophical system to be valid, it must apply to everything under its domain, which they took to be the whole of human knowledge. But the truth is that they are complementary, in the sense that their domains of applicability and validity are limited and, for the most part, do not overlap.
It was precisely this wise and sensible division of the labours of human knowledge that was made by the Scottish philosopher David Hume in his work, An Enquiry Concerning Human Understanding, at the end of which he declared, “When we run over libraries, persuaded of these principles, what havoc must we make? If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: for it can contain nothing but sophistry and illusion.”
That both Rationalism and Empiricism are true, when they are restricted to their respective domains of applicability, is shown by the facts that neither school has been able decisively to vanquish the other, and both schools continue to attract devoted adherents to their philosophical banner, something that a completely false theory would have been much less likely to do, especially when one considers how much time their adherents and critics have had to resolve this issue.
Theories about the world, whether they are about the natural or human world, are ultimately statements about the way things happen or behave in that world. The world is as it is, and not as we frequently silly, fatuous, and easily misled humans believe, imagine, or want it to be. Similarly, the processes and events which occur in the world are largely independent of our desires and beliefs about reality, except when these desires and beliefs accord with reality. We are much more likely to be able to shape and change the world to our conceptions and desires if we first make the effort which is necessary to understand the world as it really is, and not as we conceive, believe, imagine, assume, or want it to be.
 Because the ability to imagine new things is so common and widespread among humans, most people do not realize just how uncommon it may be among other organisms. Why on earth did such an ability develop in the first place? Regardless of how or why it arose, the ability to conceive ideas that are not limited to our perceptions is crucial to our ability to change the environment and refashion it according to our conceptions, ideas, and visions.
 What Do You Care What Other People Think? Further Adventures of a Curious Character by Richard P. Feynman, as told to Ralph Leighton, p. 12. W. W. Norton & Company, New York, 1988.
 Ibid, pp. 12-13.
 “Surely You’re Joking, Mr. Feynman!” Adventures of a Curious Character by Richard P. Feynman, as told to Ralph Leighton, p. 85. Edited by Edward Hutchings. W. W. Norton & Company, New York, 1985.
 It would probably be more accurate to say that the philosophy of Rationalism developed from and was encouraged by the successes of mathematics and physics, and later, chemistry, in explaining the operations of the natural world.