Occam’s Razor - a nifty problem-solving principle often attributed to a medieval Franciscan friar – is not just a tool we should all use, it is the heart of science itself and is valuable for separating legitimate ideas from superstition, pseudoscience, or fake news, according to a recent paper by a renowned Professor of Molecular Genetics.

The answer is simple(r) 

What has become known as Occam’s razor was made famous by William of Occam, a philosopher and theologian who lived in England in the 14^th century. Aspects of the idea had already been articulated by earlier thinkers, but Occam’s version is the one we know today.

The razor is essentially the idea that, when dealing with competing explanations for the same hypothesis, we should choose the one requiring fewer assumptions. It is typically expressed as “the simplest solution is usually the best one”, but while this kind of gets at Occam’s original point, this popular version is not completely accurate. But, in essence, you can imagine it with the following example:

If you’re walking down the street and you hear horse hooves clip-clopping up behind you, what is it more likely to be: a horse or a zebra? Sure, there are certain geographic locations where the latter may be more possible, but in most cases, it would be safer to assume a horse is behind you.

For instance, if you live in London and you believe it could be a zebra behind you, your explanation will require you to account for why a striped African mammal is nonchalantly trotting through a busy British city. How did it get there? Why hasn’t anyone stopped it?

If you think horse, then you need fewer assumptions to make the hypothesis fit. A stray horse in the city is pretty unlikely, but a police horse is a stronger possibility, and they are a feature of London’s police service.  

This line of thinking is not designed to say a zebra in London is impossible, just that it is improbable. But you could swap in a unicorn in the zebra’s place and your explanation for its presence in London would need even more steps, ones we know are impossible, to accommodate it.  

Just as important now as it ever was

For William of Occam, this principle was a useful way to differentiate between likely and unlikely explanations and was later adopted as a hallmark of rational thinking by individuals like Copernicus, Kepler, Galileo, and Newton. And it is just as important today as it ever was, argues Professor Johnjoe McFadden in a new paper.

“What is science?”, McFadden asked in a statement. “The rise of issues such as vaccine hesitancy, climate skepticism, alternative medicine, and mysticism reveals significant levels of distrust or misunderstanding of science amongst the general public. The ongoing COVID enquiry also highlights how scientific ignorance extends into the heart of government.”

“Part of the problem is that most people, even most scientists, have no clear idea of what science is actually about."

For McFadden, proponents of superstitious ideas or conspiracy theories work in opposition to Occam’s razor by creating more and more complex assumptions to make their explanations fit, but scientific thinking goes for simpler answers.

“Whereas practitioners of mysticism, alternative medicine, pseudoscience or fake news can invent spirits, demons conspiracies or Elvis on the moon to make sense of their world, scientists will always adopt the simplest solution to even the most complex problems. That is the beauty of Occam's razor," McFadden added.

"While mysticism, alternative medicine, and fake news often resort to elaborate explanations like spirits or moon-landing conspiracies, scientists seek the simplest solutions to complex problems. Today's world, riddled with pseudoscience and misinformation, partly stems from a poor grasp of science."

Part of the problem is that science is not taught well in most educational systems. Often it is presented as simply a “jumble of obscure theories and complex equations” which, as McFadden explained, “can overwhelm students, driving them away”.

“However, portraying science as a method to find simple explanations for our world's complexities, using experimentation, mathematics, and logic, could make it accessible to all, including politicians."

The paper is published in the journal Annals.