personal value-over-replacement

When considering one's impact on the world, it's important (? or at least tempting) to think about about your value-over-replacement. If you didn't exist, would someone else be doing your job? And would they be doing it better than you?

For example, if I got a university teaching job, the business of constantly engaging with students might feel like I'm making the world better. And of course I am really doing good, compared to the world where no teaching happens. But is that a realistic counterfactual? Not really, because if I weren't in this job, the university would hire someone else. So it seems like the bar for positive impact is not just to teach the students, but to teach them better than the next person would have. Otherwise they are worse off for your having taken this job helping them.

One might say that we should trust the system to make these choices: if I'm hired for a job, it's because my employer prefers me to the alternative. But hiring processes involve a lot of self-promotion, so my own agency and choices are relevant. And there's a big distinction between jobs where I'm just barely better than the alternative, and jobs where I'm enormously better.

This lens towards impact might be a bit misguided, because your replacement isn't "free": doing your job means they won't be doing some other important job. If there are 50 capable people, and 100 important jobs,This seems like a reasonable model of the world: there's a lot of work that would be great to do, if only we had enough talented people to do it. then a lot of important jobs will necessarily go un-done. In this world, someone choosing to do any job really does deserve a full job's worth of credit.

The value-over-replacement lens is zero-sum thinking: the model is that there are a limited number of opportunities to contribute, and by taking one, I'm crowding out someone else.Some occupations really do work this way. The supply of medical school slots in the US is artificially constrained by the doctors' cartel (the AMA), so going to med school really does crowd out someone else. Your choosing to become a doctor doesn't increase the amount of doctoring in the world. Humanities academia is also somewhat like this, with a limited (and shrinking) number of tenure-track spots independent of the number of candidates. But choosing to become an engineer, or a leader, or a nurse, does potentially increase the amount of engineering, leadership, or nursing (respectively) that happens in the world. These resources are allocated by the market, so increasing supply will lead, on the margin, to increased utilization at a lower price. The contrasting positive sum approach would be: I can create or identify new opportunities to contribute. On my own or inside an organization, I can work to carve out new roles and ways to create value.

The positive-sum view relates to the economic concept of comparative advantage. Even if I'm worse at my job than my hypothetical replacement, I may still increase overall productivity by freeing them up to do something that they have a greater advantage at. E.g., if teaching and research are equally valuable, and Dr. Amazing is a 8/10 researcher and teacher while I'm only a 5/10 teacher, then by teaching I free up Dr. Amazing's capacity to do impactful research.

Potential synthesis: as an adult making career decisions, the relevant counterfactual isn't "what if I never existed", it's "by not contributing, I waste the resources that society invested to train me". The lesson of comparative advantage is that all contributions count.