The recent discovery of two rare birds in Maine and the March for Science on April 22 provide a way to think about the power of science as a way of knowing.

On Earth Day, tens of thousands of people gathered in Washington to promote the strength of science in improving our world and advancing our knowledge. Many satellite marches were held, including several in Maine.

Scientific thinking unfortunately has little traction in our government. Of the 535 members of the U.S. Congress, only six have a degree in science or math. We have never elected a scientist as president, although Ulysses Grant, Herbert Hoover, Dwight Eisenhower and Jimmy Carter did have engineering degrees.

Yet the scientific approach has much to offer. First, science is evidence-based. As scientists, we must always be open to alternative explanations as we continue to learn. In other words, science is provisional. We must go where the evidence takes us.

Second, the scientific method embodies the notion of skepticism. We always need to question our interpretations. Although the distinction may seem subtle, scientists seek to disprove hypotheses, not confirm or prove them.

To explain a pattern, a scientist will come up with one or more hypotheses that can explain the pattern, then will design an experiment to try to knock that explanation down. If the experiment is consistent with the hypotheses, the scientist can design a different experiment to further test it. Colleagues may repeat the experiment. If the hypothesis stands up to these tests, we treat it as provisionally true. If the experiments fail to support the hypothesis, we reject it and move on to test other possible explanations. Scientists try to disprove.

The beauty of this approach is it removes ego from the process. We all have great ideas. If we try to prove them, we run the risk of cherry-picking to find information that is supportive, and ignore, perhaps subconsciously, information that would disprove a great idea.

Psychologists call this effect confirmation bias. We selectively accept observations that conform to our expectation and blithely ignore observations that don’t fit.

Professor Richard Dawkins relates an anecdote of attending a seminar by a distinguished older scientist. At the end of the talk, a student asked a perceptive question that essentially caused the speaker’s lifetime of research to crumble. Rather than becoming angry, the scientist shook the student’s hand for his role in moving science further by disproving his hypothesis.

If you ever hear someone say I proved my hypothesis, you know they don’t understand the scientific method.

Let’s go back 2,400 years to Greece. Aristotle wrote about many Greek birds. He noted that the five swallows there (including the familiar barn swallow) disappeared in the winter. He knew of no reports of these birds elsewhere during the winter. He proposed that these birds hibernate. That is a perfectly good hypothesis; it can be tested.

As it turns out, this hibernation hypothesis became part of natural history lore and was not disproven for 2,300 years. Even the great ornithologist Elliot Coues, in 1882, was agnostic on the issue. Of course, now we have the evidence that swallows migrate to tropical areas to pass the winter.

Extraordinary claims require extraordinary evidence. The recent finding of a fieldfare (a robin relative) in Newcastle and a vermilion flycatcher in Bremen on Hog Island should rightly invite skepticism. Fieldfare had never been reported in Maine, and we have an earlier sight record of a vermilion flycatcher but no photos.

Fortunately, observers provided photographs of both of these recent rarities. Those photos will certainly ensure that these sightings will be accepted by the Maine Bird Records Committee. Well done.

As birders, we should question other observers’ sightings and prepare to have our own sightings questioned.

These doubts should not be taken as insults about our abilities, but rather the proper performance of scientific, skeptical inquiry.

Herb Wilson teaches ornithology and other biology courses at Colby College. He welcomes reader comments and questions at

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