Raw Meat is a quoteblog by Aaron Swartz.

A question about marginalism

I’m often confused by marginalism and this morning a friend raised another question.

Imagine you operate an assembly line that requires six workers to produce goods. The marginal product of each worker would seem to be the entire value of the goods — after all, if any individual worker left, it’d be worth paying almost up to your entire profit to replace them, because otherwise you’d have no profit at all.

But, by induction, each worker should be able to do this, and then you’re paying out 6x your total profit, which clearly isn’t right either.

How do marginalists address this issue?