Last week we visited our son Ben at college and took him to lunch with some of his friends. He was a live wire of energy. “Mom,” he said as we walked to the restaurant, “I just love vector calculus.” There was not a trace of irony in his delivery. “It makes so much sense,” he said. And he began to explain how useful vector calculus is in predicting, say, the trajectory of a soccer ball.

I listened and tried to understand what I could. I had never thought about vector calculus; I never even studied regular calculus. I was a good math student in high school, but I wasn’t interested in it, and I never took a math class in college because I didn’t have to. So many other things fired me up.

At lunch Ben and his friends drew with chalk on the table, using their serious math skills to graph absurdities. I was entirely out of my element, couldn’t chime in with any comment at all. I could only laugh at the delightful strangeness of having a son who is a geek, who is majoring in physics, who builds race cars, who is deeply committed to martial arts, who loved jumping from a plane last summer to skydive. All that testosterone! All that passion! How different he is from me, and how satisfying that has turned out to be.

Most mornings I awaken thinking about what I will write that day, where a scene has to go, what a character has to do. Sometimes a particular word or phrase, brewing all night, is ready to hit the page. The years have honed my brain to focus and work this way.

There are certain sacrifices I’ve made for honing my skill as a writer; certain ways of thinking I’ve had to let go, mathematical logic being one of them. Some days it seems terribly sad to think that I’ll never be a surgeon (I adored dissection in high school), or a film director (I tried my hand at that for several years), or a politician (thank god). But usually the pleasure of what I have learned to do outweighs regret. I feel driven to write, the activity I have passion for, as well as I can.

And it’s comforting to know my son and his friends are out there feeling equally driven and passionate about such things as vector calculus.