What Is Teaching?

If you're going to be a teacher, a good starting point is to have a working definition of what it means to teach. This is harder than it sounds. If you look in a dictionary, you'll find a number of alternate ways of defining the word teach, most of which boil down in one way or other to something along the lines of "to impart knowledge." But this is clearly inadequate as either a definition or a goal for teaching, because if all we did was impart knowledge, then each generation would learn only what the previous generation imparted to them; in other words, our civilization would never advance. So I'll offer you what I believe to be a better working definition:

Teaching The transmission from one person to others of knowledge and of the means to acquire additional knowledge.

It's the second part of this definition that presents the greater challenge. Any good storyteller can transmit knowledge to an audience, but a teacher must also inspire the members of an audience to create their own, new stories. Indeed, while any particular course will focus on some specific set of subject matter, I'd argue that our primary goal in teaching is less for students to remember the particulars of a course than for them to "learn how to learn," so that they'll be successful in future endeavors.

It's worth noting that this definition of teaching poses a measurement problem, because it means that true success in teaching can be measured only by evaluating the long-term success of your students, meaning their success long after they've left your course. In essence, the assignments and exams that we can grade in the short term can at best tell us only some reasonable probability as to whether we've been successful teachers. This measurement problem should not stop us from trying to evaluate teaching success, but it means we must be careful to recognize the limitations of any evaluations that we use.

What Is Science?

Since this book focuses on the teaching of science, it would be useful to know exactly what science is. It's not easy to define science in a concise way; indeed, scholars who investigate the history and nature of science do not always agree on exactly what constitutes science. Nevertheless, it's clearly critical that we help students understand the basic nature of science and of how to distinguish science from nonscience, so I'll offer an approach that I've found to be successful with a variety of audiences. This approach begins by focusing on the purposes of science and then discusses key hallmarks that can help us distinguish between science and other methods of seeking knowledge.

Purposes of Science: One of the first problems we encounter in teaching science is that most students don't have a clear idea of the value of science. In many cases, students come to us with great misconceptions about the role of science in society; some even believe, for example, that the purpose of science is to undermine religion or other personal beliefs. I therefore find it effective to begin any discussion of the nature of science with what I believe to be three important purposes of science in society:

1. Science is a way of distinguishing possibilities from realities.

This statement represents the idea that in the absence of evidence, we can imagine a broad range of possible explanations for any set of phenomena. Science gives us a way to look at evidence that can allow us to determine which of those possibilities are consistent with observed reality and which are not. The classic example is the ancient debate over whether Earth is the center of the universe or a planet going around the Sun. For more than 2,000 years, the debate over the two possibilities continued almost without change — and with most people believing the possibility that turned out to be incorrect — because observations were not yet precise enough to test whether one idea offered a better match to reality than the other. Then, as observations improved during the Copernican revolution, we ultimately learned that the Earth-centered possibility simply did not agree with the evidence. Perhaps equally significant, nearly everyone supporting the alternate possibility had assumed that planetary orbits would be circular, but the data showed that this was also inconsistent with the evidence. That is what led Kepler to investigate other possibilities, enabling him to discover that Earth and other planets follow elliptical orbits around the Sun. For a simple bottom line, without science, we would likely still live in a world in which most people thought Earth to be the center of the universe.

2. Science is a way of helping people come to agreement.

This statement simply reminds us of the way science advances. We collect evidence that anyone can in principle examine, and we analyze the evidence to decide what it means. We then put our conclusions to the test by looking at what our ideas predict about what we should find in other observations or experiments. If the predictions fail, then we know we have to go back to the drawing board. But if the predictions are verified, then we think our ideas are on the right track and we can build a model of nature based on them. If the model succeeds repeatedly and in varied circumstances, then the evidence can eventually become so overwhelming that anyone who looks at it will reach the conclusion that the model is valid. Again, the Copernican revolution provides a classic example. The debate about whether Earth was the center of the universe went on for more than 2,000 years. Then, over a period of barely more than a century, the evidence became so overwhelming that virtually no one argued any further for the Earth-centered view. Stated slightly differently, it's possible to argue endlessly as long as there are no actual facts to get in the way — and only science brings us the facts and understanding that can ultimately settle the debates.

3. Science is the primary driver of technological progress.

Our society has undergone tremendous technological change in the past few centuries, and while there is room for debate on whether these changes have been a net positive or negative for the human race, there are very few people who advocate halting our technological progress. However, strange as it may seem to those of us who teach science, many people don't recognize the fact that science drives technology. For example, while nearly everyone favors advances in medical treatment, far fewer understand that these advances are connected to fundamental biology (including being rooted in an understanding of the theory of evolution). This type of misunderstanding often leads to debates about the value of fundamental research, putting at...