“Of course you should pull the lever; you’re saving four people!”

“But if you pull the lever, you’re actively choosing to cause the death of someone else. You would be violating a core ethical principle!”

“Ugh, you don’t get it. Stanley, what do you think?”

Stanley stared back at his classmates. After a few moments of silence, he responded:

“Huh. I’m not sure. I want to think about this more. Can you ask me next week?”

His classmates looked displeased, but they reluctantly agreed.

Next week, after much contemplation, Stanley had an answer for his classmates.

“At first, I was 70% confident that pulling the lever would be wrong. But after thinking about it some more, and reading some essays, I’ve changed my mind. I’m 65% confident that pulling the lever is right, though I still have high uncertainty and a few unresolved questions.”

His classmates stared back. 

“Jeez, Stanley,” one of them responded. “I can’t imagine what it’s like being inside your head.”

“How do you function with all of that uncertainty?”

Stanley simply shrugged, and the three continued their walk home.

---

At home, Stanley was studying for an upcoming philosophy exam when he noticed a splat. His fish, Percy, had plopped out of his bowl and onto the ground. Percy was floundering, deprived of water.

Stanley found himself overwhelmed with thoughts. Are fish conscious? I haven’t examined this yet… and if they are, what does that mean about how we eat them? We also eat chickens, which probably have a higher likelihood of being conscious. Also, even if Percy is conscious, is he even living a net positive life? Is a life that’s trapped in a bowl really a life worth living? And if I don’t act, am I morally responsibli--?

Suddenly, Stanley’s mother rushed into the room, grabbed Percy, and put him back into his bowl.

“Stanley! What were you thinking?” she cried.

“I… I just… I wasn’t sure what to do.”

“Sometimes, Stanley, it doesn’t matter if you’re sure. You still have to act.”

---

Years later, Stanley became a pilot. As he was flying, he noticed something strange. 

The fuel gauge showed that the plane still had 75% of its fuel. But that was impossible; Stanley was confident that he had used more fuel. Stanley started to consider possible explanations: maybe his prediction was off, maybe it was an inconsequential fluke. Or maybe it signaled that there was something wrong with the dashboard-- or worse, the monitoring system itself. 

“This is your captain aboard.” Stanley’s voice boomed over the speakers, “Please fasten your seatbelts; we’re going to be engaging in an emergency landing.”

Hours later, after the flight had landed, the airline noticed a fatal error in the plane’s power system. If it had gone unaddressed for the length of the original flight, the plane almost certainly would have crashed.

One of the fellow crew members asked, “Stanley, how did you know?”

Stanley responded, “I didn’t know. I was only 10% sure.”

“10%? You broke airline policy to initiate an emergency landing, and you were only 10% sure? Are you crazy?”

“I think I see your concern, and I agree. If I had been under less stress, my reasoning would have been better. Given all of the information I had, I should have been able to conclude that there was an 18% chance of failure.”

The crewmember stared at Stanley in disbelief.

“But the thing is, as soon as I was confident that the risk was at least 10%, I decided to stop calculating.” Stanley added.

"At that point, it didn’t matter if the risk was 10%, 18%, or 75%. My decision would have been the same.”

“Besides,” Stanley added, “It’s taken me a lot of practice. But I’ve learned that sometimes, even when you’re not sure, you still have to act.”

---

“Do you take Stanley to be your husband? Do you promise to love him, in sickness and health, for as long as you both shall live?”

“I’m sorry-- I don’t think I can honestly make that promise. I would place our odds of staying together at around 75%.”

The attendees gasped in horror.

Stanley, unfazed, responded, “I’ve always loved how well you incorporate base rates.”

With that, he kissed the bride.

---

Thank you for reading! I wanted to write about moral uncertainty and decision-making under uncertainty. 

Thinking in terms of uncertainty is weird (vignette 1). At its worst, it can lead to choice paralysis and inaction (vignette 2). But it doesn't have to-- sometimes, it can actually lead us to take very decisive action (vignette 3). And sometimes, it even leads to love (vignette 4-- this one's just for fun :D). 

Please feel free to offer feedback! I was/am quite uncertain about whether this achieves my goal (of having people reflect on uncertainty and how it can relate to cause prioritization, everyday actions, etc.). If you have ways I can make this better, or future writing better, please comment!

I'm grateful to Scott Mulligan (scottxmulligan), Alyssa Nie, Manya Gupta, and Jack Goldberg for their feedback on an earlier version of this.