Why We Need To Understand Science

Copyright ©1989 by Carl Sagan

As I got off the plane, he was waiting for me, holding up a sign with my name on it. I was on my way to a conference of scientists and television broadcasters, and the organizers had kindly sent a driver.

“Do you mind if I ask you a question?” he said as we waited for my bag. “Isn’t it confusing to have the same name as that science guy?” It took me a moment to understand. Was he pulling my leg? “I am that science guy,” I said. He smiled. “Sorry. That’s my problem. I thought it was yours too.” He put out his hand. “My name is William F. Buckley.” (Well, his name wasn’t exactly William F. Buckley, but he did have the name of a contentious television interviewer, for which he doubtless took a lot of good-natured ribbing.)

As we settled into the car for the long drive, he told me he was glad I was “that science guy”—he had so many questions to ask about science. Would I mind? And so we got to talking. But not about science. He wanted to discuss UFOs, “channeling” (a way to hear what’s on the minds of dead people—not much it turns out), crystals, astrology. . . . He introduced each subject with real enthusiasm, and each time I had to disappoint him: “The evidence is crummy,” I kept saying. “There’s a much simpler explanation.” As we drove on through the rain, I could see him getting glummer. I was attacking not just pseudoscience but also a facet of his inner life.

And yet there is so much in real science that’s equally exciting, more mysterious, a greater intellectual challenge—as well as being a lot closer to the truth.

Inconceivalbe

Impossible is a word that comes up a lot in my class, especially during discussions of physical or chemical properties. For example, electrons are often described as occupying a region (called an orbital) around an atom’s nucleus. However, these orbitals are only representations of the space where the electrons probably are. (Sort of like saying your child is probably at the mall; you can’t say exactly where, but you are pretty sure of the boundaries where they could be.) But that is not the true behavior of an electron. Electrons (like kids) don’t have to be in their orbital at all. They can be anywhere. It’s just very unlikely that they will be. In fact, it’s very, very, very, very, very, very, unlikely that they will be anywhere else other than their orbital, but it's not impossible. We say, there is a non-zero probability of finding the electron anywhere in the Universe.

The same rules apply to you. Since you are made of particles, and all your particles have a non-zero probability of being anywhere in the Universe, it is possible that you could instantly wind up on the other side of the Earth. For this to happen, all of your particles would have to simultaneously cash in their non-zero probabilities of being anywhere and simultaneously cash in their other non-zero probabilities for a new location. Unlikely, but technically not impossible.

When I mention this to my class, I am usually met with a healthy skepticism and general agreement that this will never happen. But there is always one student that insists on grabbing hold of the notion that it could happen. This is a seminal moment for those students. They are presented with a clear choice to either allow the meaning of words to be plastic; subtlety affected by the nuanced context in which they are used, or adhere to rigid definitions, unaltered by context. Impossible either is or it is not. It is not subject to interpretation.