THE ART OF UNCERTAINTY: Why Not Knowing Is Not Frightening but Useful

Sir David John Spiegelhalter is a British statistician. He currently serves as Chair of the Winton Centre for Risk and Evidence Communication at the Statistical Laboratory of the University of Cambridge / turing.ac.uk

Can we measure — and therefore understand — uncertainty? Renowned British scientist David Spiegelhalter believes we can, provided we apply statistical methods. The practical benefits of correctly understood and interpreted statistics are immense: if society is adequately informed about challenges and risks, it will be better equipped to face them.

In his new book, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk, and Luck, reviewed by the international science journal Nature, Spiegelhalter draws on his decades of experience in statistical analysis.

THE «KNIGHT» OF STATISTICAL ANALYSIS

avid Spiegelhalter, a professor at the University of Cambridge, has spent many years working to improve statistical methods. For his outstanding contributions to the field of statistics, he was awarded the Order of the British Empire and was knighted in 2014. This was the UK’s way of honoring his efforts to inform the public on how to engage with various forms of risk — particularly in areas such as climate and medicine.

In The Art of Uncertainty…, Spiegelhalter poses the question: how can we use statistical data and analysis to make informed decisions amid uncertainty? He argues that a proper assessment of risks and probabilities is impossible without critical thinking. The best decisions, he claims, are made when we fully engage this essential tool.

INTUITION VS. UNCERTAINTY: NOT AN OPTION!

The British statistician urges his readers to constantly question their own assumptions, as even seemingly simple questions can turn out to be surprisingly complex. Critical thinking, however, is a mentally demanding activity.

It’s no surprise that most people take the more «economical» route, relying on intuition to navigate uncertainty. Yet, according to Spiegelhalter, this approach has many flaws and limitations that are incompatible with truly informed decision-making.

Instead, he proposes replacing intuition with evidence-based analysis. Our lives are shaped by a complex mix of chance, ignorance, risk, and luck. Interacting in intricate ways, these four «forces» shape the course of our lives — often in the most unpredictable manner, placing us firmly in the grip of uncertainty.

A CHINESE PARABLE: HOW TO THINK PROPERLY ABOUT EVENTS

Uncertainty is a kind of vicious event loop — one that is incredibly difficult to escape. To illustrate its nature, we can turn to an ancient Chinese parable. It tells the story of an old wise farmer whose only possession was a horse. Without it, he couldn’t plough or sow.

One day, the horse ran away. The villagers rushed to express their sympathy and pity. But the old man replied, «How do you know that the horse running away is a misfortune and not a blessing?» The villagers were puzzled by his words.

Soon after, something extraordinary happened — the runaway horse not only returned but brought along a wild companion.

The villagers hurried to congratulate the old man on his stroke of luck — now he had two horses! But again, the wise man questioned them: «How do you know this is good fortune?» As you might guess, the story continues in a cycle — good and bad events endlessly replace each other.

The lesson is clear: there are no purely bad or purely good events because each new development redefines what came before.

UNCERTAINTY IS NOT A PROPERTY OF THE EVENT

To begin with, David Spiegelhalter wants to convey an idea that may seem simple at first glance but is actually quite profound for many of us: uncertainty is not an inherent property of an event. The renowned Austrian-British philosopher Ludwig Wittgenstein put it differently but pointed to the same conclusion: «The world has no intentions toward us».

When we assign certain properties to events — including uncertainty — we are not truly uncovering their essence. What we’re actually reflecting is our own knowledge, perspective, and assumptions as we attempt to understand and predict what’s happening.

This is why the «essence» of an event can appear entirely different to different people. Even when the circumstances are exactly the same, interpretations may vary greatly from one situation to another. It all depends on what we do — or do not — know at a given moment in time.

TWO TYPES OF UNCERTAINTY

According to David Spiegelhalter, uncertainty can be divided into two main types. The first is what’s known as aleatory uncertainty — that is, uncertainty about things we simply cannot know. The second type is epistemic uncertainty.

This refers to what we do not yet know. Spiegelhalter argues that if we want to make conscious, well-reasoned decisions, we must learn to distinguish between these two types of uncertainty and understand how they work.

In his view, aleatory uncertainty is often irreducible — meaning it can be acknowledged but does not necessarily need to be factored into every decision. Epistemic uncertainty, on the other hand, can be addressed. It can — and should — be minimized through statistical data collection, refined models, or deeper analytical research.

HUMILITY — THE PROPHET’S GREATEST VIRTUE

But what, beyond all this, is essential for making an accurate prediction? Spiegelhalter insists that the key condition for sound forecasting is humility — above all, humility in the face of the inevitable incompleteness of our own knowledge.

We live in an era where certain social expectations are placed on scientists — chief among them is the belief that science can explain everything rationally, thus gradually eliminating uncertainty. However, Spiegelhalter argues that society must fundamentally accept an undeniable truth: our knowledge has limits — and most likely always will.

REHABILITATING UNCERTAINTY

Even the most advanced and sophisticated statistical tools — those used for economic or climate forecasting, for instance — can prove fragile. They are often closer to informed assumptions than to definitive, one-track predictions. Yet, Spiegelhalter argues, forecasting remains valuable even when a prediction turns out to be incorrect.

What society needs is a kind of rehabilitation — a cultural acceptance of uncertainty. If assumptions are communicated with honesty and transparency, and if there is an understanding of the limitations inherent in forecasting models, this will not undermine the authority of scientists. On the contrary, it will enhance public trust.

People will begin to make more informed, nuanced decisions — and ultimately, achieve better outcomes.

«DEEP UNCERTAINTY»

Spiegelhalter also draws attention to the concept of deep uncertainty. Take, for instance, current attempts to predict what artificial intelligence might look like 25 years from now. The truth is that we cannot foresee all possible scenarios of development. We can’t even assign probabilities to them.

The humility required for forecasting lies in the honest acknowledgment of our fundamental ignorance. Unfortunately, this humility often clashes with the false certainties that dominate much of today’s public discourse.

We might say we live in an «age of disinformation», where ambiguity in communication can seriously undermine public trust. For example, when a scientist says that a «flood occurs once every 100 years», they do not mean that it happens exactly once per century.

What they’re really referring to is probability — that there is a 1% chance of such an event happening in any given year.

UNCERTAINTY IS NOT AN ANOMALY — IT’S PART OF LIFE

Spiegelhalter urges us all to learn the «art of uncertainty». Uncertainty is not a flaw in existence nor an anomaly to be eliminated at any cost. Instead, it is something we must learn to accept and understand.

In truth, uncertainty permeates everything — from the routines of our daily lives to the grand-scale challenges we face, such as climate change or global pandemics. Given the gravity of such risks, uncertainty requires our comprehension, not our rejection.

Only by embracing it as an integral part of life can we begin to navigate it — whether in making personal decisions or shaping public policy.

Original research: