He was working his loose change hard. I waited until he looked at me. Then I trained on him such a long, injured stare that he drew me to his side and scraped his chin on my bare head and kept it there, hugging me close. Why do I always feel sorry for people when they are in the wrong? I wanted to hold out and get him to apologize, but then I thought maybe it was his clumsy way of telling me a search like this was something I had to do on my own.

I went to bed early and dreamed of blackbirds rising in a flock from the ground. When they crossed the horizon, their bodies turned into letters of the alphabet. Soon swarms of small black letters were crisscrossing the white sky, but they never formed any words.

After breakfast I switched on my computer. My screen saver had seaweed and sea horses in it, though, strangely, no fish. Even if he wanted to help me, I doubted my grandfather would even remember Antonio’s last name. It’s not the kind of thing men notice. I took a deep breath and typed “Antonio Spain scientist” into Google and clicked on Images. A grid of faces sprang to the screen. I scanned, clicked, and zoomed, as if I were shopping. What did a fortysomething-year-old Spanish scientist look like? Small pointed beard or a wraparound leprechaun one? Sharp eyeteeth? Shoe-brush hair? Gaunt? Jowly? The precise, alien quality of each image confused me. Antonios galore. More Antonios than I could ever need.

There had to be another way. I went to Georgetown’s graduate student records, but when I put in the search box “Antonio 1994”—the summer I was conceived!—they asked for a last name and informed me that the online database only went back to 1998. I returned to the page of “Antonio Spain scientist” faces and clicked on one I liked the look of in the fifth row. No. He’d finished his PhD in 2000 at a university in Granada.

I abandoned that Antonio. I exited the bank of other Antonios who may or may not have been my father, and folded them up in my laptop, where it seemed to me they continued to lead a murmuring half-life. Sliding down in the chair, I tried to imagine what came next.

According to Miss Sedge, the particles that make up the solid world are not actual things but tendencies to exist. You can’t be sure an electron is here and not there at any given time. No one understands it, not even the scientists.