Cal sat on Coney Island’s boardwalk bench dunking cookies into a Styrofoam cup of milk. As he had discovered in kindergarten, the key to successful dunking was to angle cookies horizontally to slow the diffusion of milk. Dunk a cookie straight up and the milk entered on its sides and bottom, accelerating the imbibition process. Sugars dissolved, fat melted, starches swelled and there was nothing to do but watch the cookie collapse and sink. Cal was determined to save his bumukas from that fate. He had purchased the cookies from one of the many Russian groceries scattered along Neptune Avenue, and he had just a few cookies left.

It wasn’t yet 9 a.m., but the boardwalk had come to life: roller-bladers hardwired into iPhones; old ladies in babushkas, wearing shopping bags on their wrists; a homeless guy in a hooded parka that had seen far too many winters; teen-agers with cigarettes dangling from their lips and no good on their minds.

Cal locked up his bike and walked along the beach. The waves — if you could even call them that — were nothing like those off the coast of Santa Cruz, where he and Nikki had lived since they graduated from Stanford. Here, at Coney Island, the waves lapped gently; in California, they crashed vengefully. If you weren’t careful, they’d suck you in and off you’d go to the afterlife.

Three months earlier, when Cal told Nikki he was thinking of leaving California for New York, she lobbied to go with him.

“Just think!” she said. “We can live together. Wouldn’t that be great?”

Absolutely not. He couldn’t tell her that, of course, so he waited until she left for a conference in Australia and then purchased his loft, in his name alone.

“You are a total, unbelievable shit,” she screamed when she found out. Over time, however, her anger morphed into hurt, which was far, far worse. Thankfully she was 3,000 miles away. He’d have to fly back and face her at some point, tell her about JJ, but for now he had more pressing matters. He had to help JJ pass her astronomy midterm.

JJ was struggling. Milky Way, Milky Bars — they were interchangeable, for all she cared. At times he suspected it wasn’t her attitude that made studying difficult, but her belief that being an older student, 28, made learning more difficult. Not that she had said as much; she never, in fact, spoke of anything personal and he didn’t dare press.

Last semester — Spring, their first together — he helped her claw her way to a C- minus in Philosophy. She cursed her way through it as well, which was fortuitous, for had she not been sitting at the next table, muttering “bullshit” every few minutes, he might not have noticed her the Starbucks a few blocks from Hunter College.

Cal remembered looking up from his Journal of Supercomputing and clearing his throat. “Excuse me, but why do you think Descartes is bullshit?”

She looked up from her copy of Descartes’ Meditations on First Philosophy. “Because he’s an idiot,” she said and returned to her book.

She wasn’t particularly pretty —in fact, she looked quite mean — but, oh, that crazy red braid! He again cleared his throat. “Many scholars maintain that much of Western philosophy evolved in response Descartes’ writings. When he says, ‘I think, therefore I am’ — ”

 “Look, any guy who has to think about whether he exists is either crazy or has too much time on his hands.”

Cal had never thought of it that way. He cleared his throat yet again, but she ignored him.

The next Tuesday, he chanced to be walking by Starbucks at the same day and time and saw her sitting at the same table. She was twirling the tip of her braid and frowning at her book. Cal debated, then entered the shop, ordered a chai and sat at the table beside hers. He waited for a conversational opening. None came.

Cal cleared his throat. JJ seemed not to hear — it was noisy after all — so he cleared his throat more loudly.

She looked up and shot him the kind of look women reserve for men who stand too close on the subway. “Something wrong with your throat?”

He blushed but somehow got up the courage to blurt out, “I’ve always agreed with Kant — that you have to apply reason to experience or experience to reason.”

“Who the hell is Kant?”

Cal pointed to her book, The Philosophy of Kant. Something in her face changed and she looked away, embarrassed.

It took several miserable minutes to figure out what he had done wrong, and if he weren’t sitting, he would have kicked himself in the ass.

“Is it pronounced Kant?” he said lightheartedly, desperate to make amends. “I mean, it could be Cant. I can’t remember how to pronounce his name, or maybe I should say, ‘I Kant remember.’ ” Cal thought himself terribly clever, and while she didn’t seem to share his opinion, she didn’t smack him in the head with her book, which he took as a good sign. And thus began their friendship.

Every Tuesday thereafter, he tutored her in Plato, William James and Bertrand Russell; the structure of moral argument and moral justification; and, his personal favorite, existentialism, which they reviewed the week before her final.

“Existentialists weren’t into theories about life, god, etc.,” he said. “Life to them was about, well, life — good, bad, ups and downs. There was no one theory to explain it, which, I suppose, was their theory. That’s why they focused on individuality, free — “

JJ covered his mouth with her hand. “Enough.”

Her warm fingers on his lips stunned him into silence. She had never touched him before, not even when they passed pens or books between them. All he could think about the rest of the afternoon and that evening and in the weeks that followed was what it would be like to kiss those fingers … to lie beside her and listen to her breathe.

Cal trudged through the Coney Island sand and back to his bike. His sweaty body felt as salty as the ocean and he looked forward to taking a long, cool shower. In the meantime, he’d buy more bumukas and think about tomorrow and his next study session with JJ

Quasars, black holes, meteor showers — they had yet to study these. And, of course, they had to go back over the Big Bang theory. Surely JJ would find it interesting once she understood it better. How could anyone not be wowed, or even mildly enthused, by the violent cosmic pop from which all life sprang?

Cal jumped on his bike and with happy thoughts of the expanding universe, he pedaled toward home.