The trolley problem is indeed a well-known series of theoretical moral dilemmas, which psychologists use to gauge how consistently people use logic and ethics in their decision-making. Depending on how you answer, they’ll throw in enough permutations to keep it interesting. One of the better-known variants goes like this: You’re the switchman of an old-school railway. A runaway trolley comes careening down the tracks toward five people who are lying, incapacitated, on the tracks. You, the railman, can pull an emergency lever that will divert the trolley to a side track in order to save the lives of the five people, but there’s a catch. A single person is tied to the side track, and if you shift the trolley it will kill her instantly. Your choice must be made in an instant: do you do nothing and allow the deaths of five people—an act of omission—or pull the lever and divert the trolley to the side track, thereby directly killing one person?

Most people, when faced with this calamitous choice, do not hesitate: they opt to divert the train. Psychologists, though, are perverse bastards, so they upped the ante. This time, you are standing on a bridge above the trolley, an onlooker with no official responsibility. You observe the five people—still in mortal peril from the runaway trolley—and as you do, you see there is someone else on the bridge with you. It’s a tall man, craning to peer onto the tracks below. In an instant you recognize the implication: if you nudge the man over the rail, he will land in precisely the right location to stop the train. (Please note: I did not invent this ridiculous scenario. Blame the ethicists.) Now your choice is even starker: do you shove one man onto the tracks in order to spare five people? The outcome, you’ll note, is the same as in the previous scenario: one person dies in order to save five, but this time the results are skewed the other way. Almost no one would actively sacrifice the big man to save the others.

Hmm, okay, said the psychologists, noting these results. Maybe this is still too easy. How could we make this a truly excruciating choice?

Scenario number three: there is a child tied to the track. Again, you can save him by diverting the train using the switch, which will kill whoever is tied to the other track. But this time it doesn’t matter because you look more closely and realize, with a sensation that defies description, that it’s your child. You know—you know—that no matter how many people are threatened on the other side, there is no choice. This is the point where biology overwhelms logic. You’ll do whatever you have to do to save your son.

Until you see who is tethered, terrified, to the other track.

Your daughter.

PART TWO

BEFORE ARTIOVIRUS

3

Antigram

KIRA

SEVILLE, SPAIN