How alternative therapists are fooled by randomness

Amos Tverksy once said that “Man is a deterministic device thrown into a probabilistic universe.” Our brains are adept at seeing patterns where none exist – especially with phenomenon governed by probability.

In most cases, this property of our brain is harmless. But its prevalence in a field like medicine can have deadly consequences. The human body is extremely complex – we are only beginning to understand human pathology. We find several examples of doctors doing more harm than good. When George Washington had a severe bacterial illness, his doctors recommended about 2.5 litres of blood-letting, which ended up killing him sooner.  For centuries, doctors used toxic mercury to treat illnesses such as syphillis and typhoid fever. Until the 1970s, brain surgeons performed lobotomies. They severed connections in the frontal lobe of mental illness patients, leaving them far more impaired than when they entered the hospitals.

Thanks to the human body’s complex workings and its miraculous healing powers, it is extremely hard to point out what causes a patient to recover – the medicine or the body’s own immune system. Similarly, is is hard to find out what causes a patient’s condition to worsen – the disease or the medicine itself. Therefore, medicine is a field where alternative therapies such as homeopathy, acupressure and colour therapy continue to prevail. Some of these interventions do some good, mainly by piggybacking on the placebo effect, which has shown to have remarkably positive outcomes. However, when such therapists claim to cure deadly diseases like cancer, overruling the advice of medical doctors, they can lead to terrible consequences.

Let me illustrate this with an example. Let’s say a doctor has discovered that a patient has a tumour in their kidney, which has a 20% percent chance of turning carcinogenic and an 80% chance of getting cured on its own. The doctor then recommends surgery – what most people consider to be an unpleasant and risky intervention. The doctor knows that the risk of the surgery failing is 1%, but decides that it is a better bet than leaving the lump untreated.

Having received this advice (and estimates on how much the surgery would cost), the patient then goes to an alternative therapist, a well-meaning gentleman, who convinces her that surgery is both risky and unnecessary for this condition. The therapist prescribes a practice involving a few changes to the diet and a few daily exercises to stimulate certain pressure points. The patient follows this religiously, and decides against the surgical intervention.

In the days that follow, let’s say the patient was lucky and that the lump dissolves away – it had an 80% of getting cured on its own. The feedback that the alternative therapist receives is that the lump is cured due to his intervention. After all, the patient listened to him and her illness is now cured. But what he fails to understand is that the illness would have been cured in 80% of the cases without any intervention.

Here’s where things turn dangerous. This case reinforces the alternative therapist’s (and the patient’s) confidence in his treatment. He then goes on to recommend it to 100 other patients who walk into his clinic with a tumour in their kidneys. If these 100 patients choose not to undergo surgery, 80 of them would be “cured” but 20 of them would meet a tragic end. Had all hundred chosen to undergo surgery, maybe 1 of them would have had to deal with a failed surgery. Nevertheless, the 80 people would trumpet the benefits of their therapy, thereby perpetuating it despite it having done more harm than good.

Interventions often fail despite the best intentions because of the complex workings of a probabilistic world, which our mind is not equipped to understand. In most cases alternative therapy, especially for mild conditions, is harmless. But when it claims to cure deadly illnesses, it can do more harm than good with all parties remaining blissfully unaware of its terrible consequences.

Alternative therapy vs. Surgery.png

3 thoughts on “How alternative therapists are fooled by randomness

  1. Many people have trouble with probabality because we were never taught what it actually is – a measure of expected value. What does it mean to say that there is a 35 percent chance of rain today? It means that if we replayed “today” 100 times, 35 of those times would result in rain. However, the mind treats it as only two possible outcomes – either it rains or it does not. The figure 35 percent has no qualitative meaning to the mind whatsoever.

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  2. It is also probable that the 20% who died had a shorter but better “life” than the ones who were “cured of tumour” after surgery & “survived”! Alternate therapy / Ayurveda looks at a patient as a whole & modern medicine looks only at the ailment and support the belief that one size fits all.


    1. That is true – one problem with modern medicine is how super specialized it has become. It mostly treats the symptoms in isolation (like removing a tumour). But it’s hard to make the argument that people who ignore a tumour early, that turns carcinogenic later, lead a better life.


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