Aristotle observed that an object falls at a rate that is proportional to its weight. Heavy objects fall quickly, and light objects fall more slowly. Makes sense, right? For hundreds of years Aristotle’s word on this was so widely accepted as truth that there was simply no point in performing an experiment to verify or contradict it. Why bother? It was enough to say Ipse dixit, literally “he said it.” If it was good enough for the old man, it’s good enough for me. It took the righteous and contrary Galileo to proclaim what anyone who bothered could see: Look here! I drop a grape and an orange together and they fall at the same rate. This man Aristotle is either a fool or a liar.
When we look back at this episode, Galileo is always our friend. We sit next to him on the bench and chuckle. Grinning and pointing at the Aristotelian dopes, we ask him: How can all those people be so stupid?
Galileo is right not to be so impressed with us. Now as then, it happens all the time.
To choose a more recent example, why are Americans getting so fat? The answer is obvious. We’re rich, lazy, and overfed. Case closed. But the data doesn’t support the story. Exercise and caloric intake don’t correlate with weight gain. And perversely, sometimes malnutrition, poverty, and obesity appear to be best friends. What’s going on? Science writer Gary Taubes has taken on this important subject in his book Good Calories Bad Calories. Here’s a lecture of him talking about his book.
My brother Paul is an endocrinologist who is especially taken with the book. He talks about it all the time. He talks about it so much that I asked if he’d be willing to write about the book and why it matters. Happily, he agreed, and here is the result…