The rules are not absolute.

The rules are not absolute; they never are. It is true that gravity pins us to earth until it doesn't, high above our atmosphere. It is true that fluids will stay in their containers, perfectly content to slosh where poured, until you cool a liquid like liquid helium enough so that its atoms calm and move together in some strange, silent unity. Properly tamed and docile, the fluid will creep up the sides of its container, unbidden, seeking to level itself. Taming the atoms untames the liquid and it behaves in ways that don't make sense, at least to those who haven't made a living out of science. And sometimes not to those people.

Then you have those atoms, which are typical until they aren't. Usually they're properly constructed shells with even distributions of electrons until you wander across the periodic table into transition metals. Those shells take strange shapes and those metals take their extra electrons and secret them away. They don't react with other elements unless you can find a way to access the extra electrons.

These things are what we're made of, on an atomic level and on the grander scale, the one where human observation of atoms creates rules for atoms to follow -- where we seek to understand the trade of electrons that creates carbon-based matter -- how it all adds up to us, flesh and bone, speaking, bleeding, crying, laughing, sleeping, living things.

In the grocery store line yesterday I thought to teach my daughters the word "intangible." It means something you can't touch, I told them. Like feelings or the soul. What's a soul, Madeleine wanted to know. In the grocery store line with my ice cream and roasted chicken and mango lemonade I thought of reactive elements and hidden electrons and electrons so cold they change the rules of liquid.

It's what makes you who you are, I decided to say. It's what makes you happy and sad and calm and joyful and everything else you can feel. But this isn't exactly right, I think. A soul is not feelings. Or not just that, but Madeleine seems fine with the explanation for now. And I think instead that the answer is closer to something more basic. It's what makes her roar when she's angry, what makes her push when she's frustrated. It's what makes her sit up and wait for me to extend my arm at night, without saying a word, until I notice and stretch out and she snuggles into my shoulder. It's an indefinable space, a tiny space that stretches wide. Just like my arm, just like the silence before she roars, just like two electrons migrating to another atom to create something else.

These are truths, and we find comfort in them without realizing it. If I wait, my mom will always offer her arm, she is not thinking. She just does it, and the unspoken thought is made right by action.

And so I can extend this idea to what it means to stand in your kitchen at midnight, making cupcakes because you promised your children you would and they don't understand a concept like, "It got too late." As you mix the frosting you don't think, "Next I will put this frosting on these cupcakes," because of course you will. It's the whole point.

Imagine, then, sensing a movement just to your right. And turning. And seeing a perfect stranger standing in your kitchen, staring at you expectantly. This is more than just an interruption in the cooking process. The frosting is not, in fact, going on those cupcakes because so many other rules you don't think about are being violated. A stranger does not walk into your house until he does. Your heart has never known the plummeting sensation of fear until it does, there in the dimly lit kitchen at midnight. Police officers do not show up at your house with flashlights and small notepads until they do, you standing there in your pajamas feeling foolish as you let them into your messy home. "I was making cupcakes," you explain lamely. Until you weren't.

This is a cellular level change, see, a sudden understanding of how essential the rules are. Underneath we are swirling, pinging masses of electrons. It all adds up into a soul, somehow. Until it doesn't. I gave something up that evening, much like an atom would give up its electrons. Everything should be different now -- cold helium creeping up walls and bodies floating in space -- and they are, I guess. A new awareness, locked doors, lights on, a cold creep of fear when I'm standing at the kitchen counter, a kitchen knife near the bed.