The desire for certainty is a powerful human emotion, and dispensing with uncertainty is a prime motivation for many endeavors and decisions. But even when we seemingly put uncertainty at bay—we choose a career, our elected officials tighten legislation to address pollution, the Federal Reserve Board lowers interest rates to spark economic activity—we never know how those decisions or actions will turn out. Whether we like it or not, uncertainty is ever present.
Many of us, however, tend to think science provides definitive answers. After all, science explains why and how things happen. Science solves problems. Scientists make predictions about our future.
But much as we may want scientific findings to be definitive, they are not. Scientists do not operate with 100 percent certainty. Findings are based on probabilities. New evidence can invalidate predictions and even modify well-accepted understandings. In many respects, uncertainty is critical for science because it spurs scientists to engage in further investigation and research.
It is important to understand that scientific uncertainty does not mean the science is flawed. Rather it means an absence of certainty and in science, it’s okay to have uncertainty. Scientists do not expect that every finding will be the last word. More often, those findings are just the beginning.
However, the lack of certainty often causes problems when science and emotion collide. It can paralyze policy makers and elected officials contemplating legislation. They need certainty to convince the public of the rightness of the proposed action—particularly if the decision involves economic pain.
The following from the Union of Concerned Scientists, a science-based nonprofit with more than 400,000 members, speaks to science and uncertainty:
In science, there's often not absolute certainty. But, research reduces uncertainty. In many cases, theories have been tested and analyzed and examined so thoroughly that their chance of being wrong is infinitesimal. Other times, uncertainties linger despite lengthy research. In those cases, scientists make it their job to explain how well something is known. When gaps in knowledge exist, scientists qualify the evidence to ensure others don't form conclusions that go beyond what is known.
Even though it may seem counterintuitive, scientists like to point out the level of uncertainty. Why? Because they want to be as transparent as possible and it shows how well certain phenomena are understood.
Decision makers in our society use scientific input all the time. But they could make a critically wrong choice if the unknowns aren't taken into account. For instance, city planners could build a levee too low or not evacuate enough coastal communities along an expected landfall zone of a hurricane if uncertainty is understated. For these reasons, uncertainty plays a key role in informing public policy.