“That’s not what I mean. I don’t want to get stuck doing something that doesn’t mean anything to me. This track I’m on? It goes on forever. Yale. Medical school. Residency. Marriage. Children. Retirement. Nursing home. Funeral home. Cemetery.”

Maybe it’s because of the importance of the day, maybe it’s meeting her, but right now it’s crucial to say exactly what I mean.

“We have big, beautiful brains. We invent things that fly. Fly. We write poetry. You probably hate poetry, but it’s hard to argue with ‘Shall I compare thee to a summer’s day? Thou art more lovely and more temperate’ in terms of sheer beauty. We are capable of big lives. A big history. Why settle? Why choose the practical thing, the mundane thing? We are born to dream and make the things we dream about.”

It all comes out more passionately than I intend, but I mean every word.

Our eyes meet. There’s something between us that wasn’t there a minute ago.

I wait for her to say something flip, but she doesn’t.

The universe stops and waits for us.

She opens her palm and she’s going to take my hand. She’s supposed to take my hand. We’re meant to walk through this world together. I see it in her eyes. We are meant to be. I’m certain of this in a way I’m not certain about anything else.

But she doesn’t take my hand. She walks on.

WE ARE HAVING A MOMENT I don’t want to be having.

When they say the heart wants what it wants, they’re talking about the poetic heart—the heart of love songs and soliloquies, the one that can break as if it were just-formed glass.

They’re not talking about the real heart, the one that only needs healthy foods and aerobic exercise.

But the poetic heart is not to be trusted. It is fickle and will lead you astray. It will tell you that all you need is love and dreams. It will say nothing about food and water and shelter and money. It will tell you that this person, the one in front of you, the one who caught your eye for whatever reason, is the One. And he is. And she is. The One—for right now, until his heart or her heart decides on someone else or something else.

The poetic heart is not to be trusted with long-term decision-making.

I know all these things. I know them the way I know that Polaris, the North Star, is not actually the brightest star in the sky—it’s the fiftieth.

And still here I am with Daniel in the middle of the sidewalk, on what is almost certainly my last day in America. My fickle, nonpractical, non-future-considering, nonsensical heart wants Daniel. It doesn’t care that he’s too earnest or that he doesn’t know what he wants or that he’s harboring dreams of being a poet, a profession that leads to heartbreak and the poorhouse.

I know there’s no such thing as meant-to-be, and yet here I am wondering if maybe I’ve been wrong.

I close my open palm, which wants to touch him, and I walk on.

ACCORDING TO SCIENTISTS, THERE ARE three stages of love: lust, attraction, and attachment. And, it turns out, each of the stages is orchestrated by chemicals—neurotransmitters—in the brain.

As you might expect, lust is ruled by testosterone and estrogen.

The second stage, attraction, is governed by dopamine and serotonin. When, for example, couples report feeling indescribably happy in each other’s presence, that’s dopamine, the pleasure hormone, doing its work.

Taking cocaine fosters the same level of euphoria. In fact, scientists who study both the brains of new lovers and cocaine addicts are hard-pressed to tell the difference.

The second chemical of the attraction phase is serotonin. When couples confess that they can’t stop thinking about each other, it’s because their serotonin level has dropped. People in love have the same low serotonin levels as people with OCD. The reason they can’t stop thinking about each other is that they are literally obsessed.

Oxytocin and vasopressin control the third stage: attachment or long-term bonding. Oxytocin is released during orgasm and makes you feel closer to the person you’ve had sex with. It’s also released during childbirth and helps bond mother to child. Vasopressin is released postcoitally.

Natasha knows these facts cold. Knowing them helped her get over Rob’s betrayal. So she knows: love is just chemicals and coincidence.

So why does Daniel feel like something more?

THERE ARE EXACTLY NO ITEMS on the list of things I want to do less than go to my interview. And yet. It’s almost eleven a.m., and if I’m going to go to this thing then I need to get gone.

Natasha and I have been walking along in silence ever since The Moment. I wish I could say it’s a comfortable silence, but it isn’t. I want to talk to her about it—The Moment—but who knows if she even felt it. No way does she believe in that stuff.

Midtown Manhattan is different from where we first met. More skyscrapers and fewer souvenir shops. The people act different too. They’re not tourists out for pleasure or shopping. There’s no excitement or gawking or smiling. These people work in these skyscrapers. I’m pretty sure my appointment is somewhere in this neighborhood.

We keep walking and not talking until we get to a giant concrete and glass monstrosity of a building. It amazes me that people spend their entire days inside places like this doing things they don’t love for people they don’t like. At least being a doctor will be better than that.

“This is where I’m going,” she says.

“I can wait for you out here,” I say, like a person who doesn’t have an appointment that will determine his future in just over an hour.