Black Swans – The Basis of Scientific Reasoning

A recent conversation with a barrister demonstrated a general misconception regarding science and the scientific method. The conversation revolved around the concept of ‘evidence’, and as the debate waxed and waned the barrister, rather surprisingly, stated, ‘I’m not sure I believe in science’. It became clear that this highly educated and intelligent individual was labouring under a misapprehension – that science was somehow a system of ‘belief’. He had fundamentally misunderstood science and the scientific method.

An appreciation of science and the scientific method requires a profound understanding of three integral principles, which distinguish science from pseudoscience and dogma. The first principle is that science is not a system of belief. A scientist does not have to believe anything, but requires the ability to reason based on the weight of evidence provided, to suspend judgement where the evidence is weak, to continue to look for answers and to keep an open mind. The Socratic Method and Russell’s teapot analogy are two examples that may be described to illustrate this principle.

The Socratic Method (or elenchus), often used as the basis for teaching the law, is named after the classical Greek philosopher Socrates (469–399 BC). It is a form of inquiry and debate between individuals with opposing viewpoints and based on asking and answering questions to stimulate critical thinking. Simply stated, the Socratic Method is to ‘question everything’. Plato attributed to Socrates the discovery of this method, which he regarded as the essence of the scientific method. According to Plato, the Socratic dictum was that ‘the unexamined life is not worth living’.1 Therefore, everything must be questioned, even one’s own ideas and, for want of a better word, ‘beliefs’. Socrates advocated this concept so strongly that he was willing to give up his life for it. According to Plato’s Apology, Socrates questioned and debated men considered wise by the people of Athens and concluded that, while each man thought himself to be knowledgeable and wise, in fact they lacked both knowledge and wisdom.1 Socrates concluded that he was the wisest, for he was the only person aware of the limitations of his knowledge. He stated, ‘I know nothing except the fact of my ignorance’.2 Perhaps this remains the definition of a truly wise individual. The Athenian elite accused Socrates of corrupting the minds of the youth of Athens and of impiety, i.e. not believing in the gods of the state. He was warned to stop teaching the young, to which he characteristically replied, ‘Why?’ He was subsequently sentenced to death by drinking a mixture containing poisonous hemlock. He died as he had lived, questioning everything.

The concept of belief without evidence was further illuminated, with characteristic clarity, by the mathematician-philosopher Bertrand Russell (1872–1970). Often termed Russell’s teapot analogy, or the celestial teapot, Russell explained that if he claimed that a teapot were revolving in an elliptical orbit somewhere in space between the Earth and Mars, it would be nonsensical for him to expect others not to doubt him on the grounds that they could not prove him wrong.3 The purpose of this analogy was to illustrate that the burden of proof lies upon the individual making scientifically unfalsifiable or as yet, unsubstantiated claims rather than shifting the burden of proof to others. Assertions made without evidence should be dismissed until justifiable evidence is provided.

The second principle that underpins science is that the scientific method demands replication of the results. Each phenomenon must be re-examined, preferably by independent and impartial investigation, and the interpretation given to it confirmed or discarded through dispassionate analysis and experimentation. The most widely read sections of any published scientific article are likely to be the abstract and the conclusions. Postgraduate trainees often quote published articles as evidence to support their statements, having only read these sections. Yet the most important section of any scientific article is the ‘materials and methods’. This is the section that will demonstrate to the discerning eye how much care has been taken by the researchers to reduce the likelihood of unintentional bias. It will also permit another researcher to undertake the same experiment. If the original researchers’ findings are not repeated, then one has to begin to doubt the accuracy of the data, and further investigation is required.

The third principle of science is the evolution of ‘scientific truth’. It is the concept that there are no final or absolute truths in science; i.e. science is always evolving as new evidence becomes available. This tenet of science was described most eloquently by the philosopher Karl Popper (1902–1994), creating arguably the most important maxim for all scientifically inquiring minds:4 ‘No matter how many instances of white swans we may have observed, this does not justify the conclusion that all swans are white.’ Stephen Hawking reiterated this view, stating: ‘No matter how many times the results of experiments agree with some theory, you can never be sure that the next time the result will not contradict the theory.’5 Therefore, great conviction in often deeply held beliefs, no matter how psychologically attractive, is not a substitute for evidence. This is particularly true where those portraying such convictions have some other vested interests.

In the past few years, aspects of dentistry and orthodontics in particular, appear to have fallen somewhat into the realms of pseudoscience, more akin to astrology than astronomy. Unfortunately, those guilty of perpetuating their dogmatic beliefs often do so under the guise of science. The following phrases, taken from recent articles in the dental press, serve as examples of the extremes of unlettered nonsense currently being thrown at dentists. These include the bellowing rivalry between the various bracketeers and their respective ‘treatment philosophies’, e.g. Bracket [X] is ‘faster, more comfortable and produces better quality results’; to the absurdly authoritarian ‘I am a non-extraction orthodontist’ (does this self-contradictory pronouncement mean ‘I don’t bother with diagnosis’?), to the hopelessly misleading ‘general dentists can use this [plastic positioner] to treat the most complex malocclusions’ etc. It appears that clinicians are not immune from the timeless, yet unpalatable truth so eloquently imparted by perhaps our greatest social critic, George Orwell (1903–1950), that ‘money controls opinion’.6 But, though the individuals comprising many professions evidently are primarily self-interested, should those involved in healthcare provision not be expected to rise above such base desires and do better?

Organised pseudoscience, often either led by market interests or an aspiration for fame, has various dogmas attached to it, which its followers are supposed to accept willingly, without doubt or questioning. The perpetrators are marked by hypocritical, condescending self-righteousness. Their sanctimonious displays, whether in writing or more frequently at the lectern, are designed to dogmatically exploit the unwary, without regard for truth. This devalues and belittles our specialty, and stamps on our professional integrity. Any form of guru worship will inevitably cloud the mind as it rests on rigid doctrine and dogma, and thereby discourages clear thinking. Science has a very different way of looking at things. It takes nothing for granted and has, or ought to have, no dogmas. It seeks to encourage an open mind and tries to reach truth by repeated experiment. The scientific outlook must lose any pride of certainty.

It is our collective responsibility to oppose the transparent fables and meaningless assertions perpetuated by hypocritical ‘clinicians’, puncturing their lies and consigning them to marginality and eventual irrelevance. Misleading statements or downright lies should be consciously contested, and not discreetly tolerated, both by individual clinicians and by the learned societies representing the profession. It is also vitally important that graduate students bring a certain inquisitive curiosity and healthy scepticism to their studies, and are educated for what Albert Einstein referred to as ‘independent thought’.7 They are not here to thoughtlessly worship what is ‘known’ or ‘believed’, but to question it. The motto of the Royal Society, perhaps the oldest learned society for science and scientific endeavor, is ‘Nullius in verba’, which roughly translates as ‘Take no one's word for it’. It is an expression of the determination to withstand the domination of authority and to verify all statements by an appeal to facts determined by experiment. Progress requires humility in the face of facts, not arrogant beliefs in the absence of evidence. At the forefront of the scientific mindset must be the knowledge that no matter how deeply convinced one may be of a theory or how deeply one hold’s an opinion, there may be a black swan just round the corner.