[gjm11]

> How can you reconcile the opportunity cost to society [...]

There are two fine institutions that may help with this: taxation and charity. If you earn a lot of money, then you pay a lot of taxes and can afford to give a lot away.

Everyone likes to complain about taxation, but it's what turns a free market full of individuals and corporations all (to a good first approximation) trying to maximize their own wealth into something that benefits everyone.

And the most effective charities seem to be able to save a life (or provide a kinda-equivalent amount of other benefits) for something in the vicinity of $2000. (Important cautionary note: all such figures are very rough and you shouldn't trust them too much.)

So, suppose you have a choice between a quant-finance job of, let's suppose, exactly zero social value, and a job in medicine that pays $50k/year less. And suppose you'd be equally happy in either aside from ethical concerns. Then by taking the quant-finance job and giving away all your extra earnings, you give your government (let's say) an extra $20k/year to spend on schools and hospitals and police and roads -- and, unfortunately, various other things you might approve of less, so let's say it's the equivalent of $10k/year going to something obviously valuable like teaching, so you're paying for about 20% of an elementary-school teacher. And you give an extra $30k to (I hope) very effective charities, so maybe you are saving 10 lives a year.

So it comes down to the question: is the medical job more beneficial to the world than 20% of an elementary-school teacher and 10 poor Africans' lives per year?

You might answer that either way, but at any rate I don't think it's obvious that the answer is that the medical job is better.

(Some notes: I am not claiming that anyone who goes into finance in preference to another worse-paid job is obliged to give away all the extra money they earn. Only that doing so is one option, and that it might work out pretty well ethically speaking. It might be psychologically difficult to give away so much of one's earnings. It might be harder to "derive meaning and satisfaction" from things as indirect as tax and charity, compared with deriving them from one's actual work. It can be argued that quant-finance has positive social value, but I'd be skeptical of claims that it has much. I do not work in finance and never have, though being a mathematician it's always possible that one day I might.)

[NhanH]

If the financial job in question is an exact zero sum job (with 0 social value), then neither taxation nor charity would help at all, because essentially while doing your job you're already causing a negative value to someone else. And even if you give always ALL your wealth, you'd just return those wealth back to society. In essence, after a lot of shuffling of wealth around, you still didn't contribute anything. (And again, that's an "IF". I'm not stating whether the premise - financial job is a zero sum game - is correct or not.)

[makeset]

Doubtless there are roles within the financial industry deserving of the "vampire squid" label in social impact, but I'd expect them to be fairly obviously unethical if not outright illegal on inspection (deceptive sales of risky exotic derivatives comes to mind). Quantitative pricing of exchange-traded products (e.g. HFT) is much harder to argue against, IMO. To me it seems like a clear net positive to process information better than others to offer more competitive prices to anonymous buyers and sellers, because tightening spreads means more efficient markets through better price discovery. It doesn't sound very different than a retailer undercutting prices by running a leaner business than the competitors and afford lower profit margins. Of course the competitors are screaming bloody murder, but how is this not good for society?