When I was eleven years old, I told my dad I wanted to invent a time machine. He told me he already had one. I asked him where it was.
“Right here,” he said. He tapped his forehead and smiled. “All I have to do is close my eyes, and I can travel back in time as far as I want.”
“That’s not time travel, Pop” I said. “That’s just remembering stuff that happened.”
He shook his head. “I don’t just travel to places I’ve been. I can go anywhere, at any time. I can go back and be a caveman, or a sea explorer, or a Civil War general. Or I can go forwards, to when we find a cure for cancer, or when the first man lands on Mars. Or,” he said with a wink, “to when someone invents a time machine.”
“So, you’re talking about imagination, then,” I said. “Making up stories.”
“Maybe,” he said. “Maybe not.”
After that, I dropped the subject. There was no point in arguing with him. He just didn’t get it.
Pop died a few months later. He never got to see me graduate from high school, or from Harvard. He never saw me earn my PhD in quantum physics from Princeton. He never saw me get married, or have kids, or win the Nobel Prize. He never saw my time machine.
But sometimes, when I’m walking across campus on the way to my lab, I’ll catch a glimpse of someone who looks like him, smiling at me.
And I think, maybe he did.