I watch you notice the bird chirping on the neighbors' air conditioning box working to nest his children in the metal vents with sticks and thread. You gasp and point, press your cheek to mine, look with me to the warbler's perch. Eye to eye, we watch his messy but deliberate process. Suddenly, he takes flight.

The eye is an imperfect instrument made adequate by aeons of messy evolution from an underwater lens to one that translates light refracted through air. Our bodies have had to compensate with generations of mutation, making this end result make sense out of practical necessity. We marvel at its complexity and precision, though we could have mended its inefficiencies had we known where we'd end up. But we didn't. We had to make our way slowly to become a foreign lifeform, swimming and dragging ourselves to land with fingerless flippers out of our aqueous atmosphere, squinting in the hazy sunlight, assessing the risk of never going back.

This moment, your soft eyelashes rest on round cheeks pressed against my empty breasts. Your breathing, my heartbeat, this relationship with you outside of my body, reminds me of the messiness of birth. More blood and effort and pain than we would have planned had we known our heads would grow so large, our pelvises would narrow, our society would make it difficult to keep well the bond between mother and child. But here we are, our rhythms syncing, the heaviness a comfort, the birdsong an ideal lullaby.

The way you throw your head back to see the moon and stars as we walk at night looks like the beginning of a back flip, motion that defies the grounding physics of gravity. The moon feels like it could rest in a hand like an orb, but its orbit dictates our internal tides. We look up at the moon looking down on a planet it doesn't know houses humans. The way you look at me in delighted puzzlement at the distant lights in darkness is the start of a lifetime of questions.

Why only five fingers and toes, and no fewer? Why does the smell of your breath make me smile? Why feathers on birds, scales on fish, skin on humans? Why sex, or pain, or laughter? Why delight in observing life? Why death, instead of living forever?

Nothing would be the same if we'd known it was becoming. Nothing would mean anything without a history, but nothing happens for a reason except that it has to happen that way for the world to get where it is going.

Our eyes are the same as the bird's nest, brown and rich, empty for holding. Your wonderment is the Earth's bedtime story, telling us what could happen if we dreamed. The mystery of what we will become is foretold in the bird's flight, is written in blood, is promised in song.