I loved a boy once who loved science. He'd greet me at the end of the school day like a happy puppy, full of ideas and affection and energy. Bounding to my side he'd babble about what he'd learned that day, bringing me lectures and theorems like chewed sticks or spittled rubber balls. As if I understood half of what he brought home. I wanted to, though. Really.

One day he carried home the Heisenberg Uncertainty Principle, and this is where the real trouble begins. You can discuss an electron with a four-part description: position, momentum, energy, and time. These qualities not only describe the electron, they also describe each other. For example you can’t discuss the position of an electron without addressing its momentum; nor can you discuss an electron’s energy without factoring in time. Canonical conjugates, they call ‘em: two properties that have a special relationship. When he told me about these couples, I thought of us, a pair with a special relationship. I liked this Heisenberg. "Tell me more, dearest."

"The more you know about one half of the pair, the less you can be certain about the other. You have to acknowledge that, no matter how precise your tools, there's always an element of inaccuracy in your measurement. And the more you try to increase the accuracy of that measure, the more uncertainty you introduce. The more precisely you measure an electron's position, the more difficult it is to nail down the measurement of its momentum. The same with time and energy."

"So... basically what you're telling me is, "Physics is a bitch."

"Not at all! Heisenberg had made a terrific discovery!" He was using the voice he normally reserved for concerts and poker games. His hands were gesturing wildly. I couldn't help but smile.

"Well how can uncertainty be a terrific discovery? Isn't that bad news?

"Heisenberg discovered that the amount of uncertainty produced by any given conjugate pair couldn't go below a specified constant. He measured inaccuracy! He reasoned that, regardless of the scientist or the precision of their tools, there would always be at least some small amount of uncertainty. It's brilliant."

"So if we know how much uncertainty there is, we can tell how much certainty we have?"

"Precisely," he said. Or would have said, if he hadn't leaned in quickly to kiss me hard. That was the end of Heisenberg, for a while.

My love came home another day with an idea called the Amsterdam, or Copenhagen--something Interpretation. He thought, since I'd been so interested in electrons and their measurement, that I might like to know about superposition. He told me how, when no one's looking, electrons exist in all possible states at the same time. They're more like waves of probability, and they'll take every possible path from point A to point B.

"When we shine a light on them, they choose a path. But by shining the light, we've tampered with them. If we look away again, the electron returns to its superposition." This I didn't grasp so easily at the time, but I think I understand now.

More frequently we avoided discussions about what I knew or what he'd learned. Our conversations began to center around our relationship. Foolishly, I wanted to define "us." I needed the security of a label, I needed to pinpoint where we were. I should've taken a cue from Heisenberg, and focused on where we weren't.

Months went by and the conversations turned bitter. What had once been a relationship with endless possibility had turned into a cramped exercise in dueling. If I loved him, why didn't we make love more often? If he wanted to be with me, why weren't we engaged? I wanted us to last forever, but the tighter we gripped our love the more it slipped between our fingers until eventually it had disappeared. What can I say? Love is a bitch.

Which brings us back to Physics. Without his guidance, I can't be sure I've got this right but every piece of me that misses him says it's so. You see the real trouble with love is that it's the most complex thing out there--more complex than any Superstring Theory or Strong Law of Small Numbers. I can think back to our superposition, the very moment we clicked, that instant rush of "this could be the one." All things are possible in that instant. There were an infinite number of paths that our relationship could take and this... well, this just kills me. I should've observed less and been more. I'm no physicist, no great philosopher or scientist, but I know what possibility is.

You'll never know for sure if your love will last forever, or if your husband will be faithful, or if your girlfriend feels the same way you do. And the more you try to define your relationship by exactly measuring its components, the more you change the relationship.

But here's the catch: just the way the Uncertainty Principle applies even when no one's altering anything, your relationship is changed whether you set out to define it more accurately or not. Because when you don't bring up things like commitment and trust and passion and where-are-we-going, your partner is in some way affected by your lack of question. I had to know what he thought about us together, and when he didn't share that, I took it to mean that he wasn't thinking about us together.

I should've been thinking. I should've done what the scientists do. If we know how much uncertainty there is, we can tell how much certainty we have. Neither of us knew where things were going exactly but that should have been okay. That was a marginal amount of uncertainty in exchange for so much love. I should have seen that the present was certain; that although the future was in the air, I knew he wanted to be with me right then. The certainty is what matters. They couldn't give a Nobel prize for love--it's much too complicated.

Thank you to Positronicmoron, wazroth, IWhoSawTheFace, jbo, Kensey, and countless others who've had to put up with my rambling.