Learn to Think Like a Scientist
It was Sunday afternoon in fast-moving Manhattan, but the crowd entering the newly opened Darwin Exhibition at the American Museum of Natural History only had eyes for the slow-motion moves of two giant tortoises.
Gawkers of all ages seemed to be simulating Darwin's own sense of wonder upon discovering these curiously distinctive creatures during his visit to the Galapagos Islands in 1835. But Darwin's initial observations, the exhibit shows, didn't stop there. His encounter sparked years of investigation and analysis of thousands of insect, plant, animal, and fossil samples he collected during his five-year voyage on the Beagle. To this evidence, already substantial, he added more: countless experiments in his greenhouses in England, as well as further investigations into geology and animal breeding. Only in 1858 did he publicly present what eventually became known as his Theory of Evolution: All life evolved from a common ancestor through the process of natural selection.
Yes, a theory. But far more than "just a theory."
That's the dismissive tag "intelligent design" advocates often use to try to discredit evolution. It resonates in the public consciousness, says Case Western Reserve physics Prof. Lawrence Krauss, because most people aren't aware that the word theory has a different meaning in a scientific context.
A scientific theory, he explains, is a comprehensive, logical explanation of natural phenomena. And it's not based on a mere hunch. Rather, it rests upon verifiable evidence, observation, and experiments that can be replicated. That's what Darwin did. For example, he saw that tortoise shells and finch beaks in the Galapagos differed from island to island. Further study helped him formulate his theory: Through evolution, the animals adapted to their environment.
Scopes again. Recent attempts in Pennsylvania and Ohio to introduce intelligent design into the school science curriculum represent the latest "step in the continuing process which began with the Scopes trial in 1925," says Paul Gross, former head of the Marine Biological Laboratory at Woods Hole, Mass. Intelligent design is based on faith, not science, he explains. You can believe it or not, but you can't establish scientific proof for it.
Confusion about the use of the word theory speaks to a general lack of scientific knowledge in the United States. In a review released this month of how well states meet academic standards for science in grades K-12, more than half received a C or lower, and 15 flunked.
Yet now more than ever, we face "hundreds of issues that affect our lives" that are basically about science, says Gross, who was the lead author of the Thomas B. Fordham Institute-sponsored study. Global warming is one: "To what extent is it a consequence of what human beings do, rather than natural and physical cycles? Obviously, this is a very important question, and as citizens we are constantly faced by a barrage of statements that are often political." For example, Henry Pollack, a professor of geophysics at the University of Michigan and author of Uncertain Science ... Uncertain World , points out, "describing atmospheric carbon dioxide and methane as 'so-called greenhouse gases' creates doubt that they affect the temperature of the atmosphere--an impression that no atmospheric scientist would affect." But to assess their validity, we need to understand enough science to ask relevant questions.
Learning to think scientifically is not a skill solely for the domain of science. Pollack explains, "In any field, it's important to learn to differentiate between what's real and what's phony. You ask: 'Can this be true? How can I test if it's true?' It's going a lot deeper than 'Hey, I have a good idea!' " When that process is followed thoroughly, through experiments and observations, yielding evidence to back up the idea, only then is it known as science.
Michael Shermer, editor of Skeptic , sums up scientific reasoning.
1. Ask a question: Is the Earth round or flat?
2. Experiment. Devise tests to answer the question.
3. Confirm. Find other data, observations, experiments, or research to back up your evidence.
4. Conclude. With a body of data (and no contrary evidence), you can say: Yes, the Earth is round!
This story appears in the December 26, 2005 print edition of U.S. News & World Report.