Of the many characteristics shared by scientists and zen practitioners, an acceptance of uncertainty is notable. Most humans do not actively—even joyously—embrace it.
Zen asks us to recognize that some things are unknowable at any given moment, and that’s okay. We should get used to the idea that uncertainty is just part of the world we experience, and it is neither good nor bad. By accepting that we can’t always know the truth, we worry less and feel more comfortable with our lives.
Scientists learn to do the same, but for different reasons. We need to account for uncertainty in everything we do, particularly if we are trying to improve the accuracy of our predictions.
For example, you may have noticed ‘error bars’ around an estimate on a graph: they tend to look like skeletal dumbbells resting vertically around points on a line or at the top of bars on a bar chart (histogram). These markings provide a visual gauge of uncertainty.
Error bars are usually mathematical in nature. For each point on a graph that shows an estimate, a dumbbell is calculated which reminds us that we can’t just simply use the number here; we must also take into account a range of numbers that represent the ‘unknown’ associated with the estimate.
Error bars are formal uncertainty, and every scientist has to come to terms with them.
Yet scientists, like other humans, find it challenging to do so. We feel a desire to know truth, a desire that is perhaps fundamental to the human psyche. But close observation will show any of us that our world rarely provides certitude. Experience helps us to see that.
The protagonist in Roald Dahl’s story Man From The South makes an extraordinary wager that his cigarette lighter will ignite ten times in a row. He does so because he thinks the lighter has never failed him before. But the story is famous because of the tension that builds precipitously with each successive attempt to light the lighter. The Boy realizes that his ‘infallible’ lighter has a very real chance of failing—that his previous certainty in his lighter has an inescapable complement of uncertainty. And because the consequence of failure is dire (the loss of a finger), that uncertainty becomes an almost paralyzing misery in his attempt to win the wager.
When forced to face uncertainty, humans become physically and mentally anxious. If the uncertainty is relentless, we might even chose to create certainty in our minds where none exists around us. This craving for stability in certainty has led humans down very dark roads.
Like those people who direct their thinking to see a gray world as either black or white, some folks simply choose certainty of ideas despite the absence of evidence to justify them. That is one of the reasons we demand that scientists account for uncertainty—it ought to prevent us from misleading ourselves and others about an idea we like simply because we wish to have a definitive answer.
Scientists, then, must work daily with uncertainty. The skill is rarely natural and a good mentor can help. I train new scientists to consider the boundaries of an hypothesis, to ponder observations both expected and unexpected, to accept and work within the limitations of a mathematical model, to question whether an experiment went according to plan, and to acknowledge any compelling but strange observations that might point to an unexpected explanation.
With time and experience, they each grow more comfortable with the ‘unknown’ in a system. But being human, they rarely let it stand as is: they often adopt a sense of assurance that more investigation will explain the unexplained. They use phrases like “we’re finally getting to the bottom of it”, which can only serve as a comforting thought that one day an unknown will become a completely known, despite all historical evidence to the contrary.
As a peer reviewer of scientific papers, I am continually asking authors to show the uncertainty in their work: error bars on estimates, a discussion of a model’s limitations, their estimate of data quality, the effect of cascading uncertainty in a multistep analysis, and the curbing of their overstatements about the meaning of their results.
Scientists must do this. It’s easy to ‘slip up’ and gloss over uncertainty, especially when there is a good story to tell. But that’s just the point: often it is a good story only because the uncertainty has not been revealed.
It helps us to remember that even a ‘law’ of physics has uncertainty. Situations never before experienced, examined, or even considered can make a ‘law’ less law-like. A fine example is Newtonian physics, so useful and dependable, which after several centuries was discovered to have special circumstances in which ‘corrections’ are required. Albert Einstein outlined these in his theory of General Relativity.
I expect we will make science an endless endeavor to attain—but never quite reach—absolute certainty. And I hope we can all learn to live with that. A good scientist is comfortable with uncertainty, recognizing that every idea, every explanation, every prediction comes with a non-zero quantity of ‘unknown’.
Embrace it! That’s just how the world is—or at least appears—to us.
What is under-appreciated by scientists is that their ability to work with uncertainty has put them in an excellent position to practice Zen.
