Economists like to separate the "positive" and "normative" aspects

What do you owe the world, and what does the world owe you? from Marginal Revolution by Tyler Cowen

Every now and then I feel a deep responsibility to rebut an argument. In my view anyone doing policy economics has an obligation to learn more about ethics -- much more -- than the guy in the street would know. Would someone doing experimental economics feel free of the obligation to learn some empirical psychology? Would someone doing trade feel free of the obligation to learn some trade law, some history, and some political science? No. What's the difference? Economists like to separate the "positive" and "normative" aspects of what they do, but this distinction has not much impressed the moral philosophers who have looked at it nor has it impressed Amartya Sen.

The very decision to use economic tools emphasizes some considerations and excludes others. The final policy analysis is not just pure prediction but rather it is also an implicit presentation and weighting of both different kinds of information and different values. So if you are doing policy economics, it is imperative that you think about ethics at a very deep level, and read widely in ethics. You are doing ethics whether you like it or not! Furthermore I don't doubt that Dani already has a deeper understanding of ethics than the (often very crude) man in the street.

That said, I don't agree with the ethics Dani does discuss, noting that he must have felt he had some good reason to put forward the concerns he did and not others. (As a rule of thumb I'll note that those who profess the impassability of ethical terrain have just in fact traversed it.) I don't worry much about the procedural fairness if a poor country trades at better prices by paying its labor less or by polluting. Low wages are precisely the wages we want to see bid up, and if there is a concern for the losers I would not call the issue a procedural one but rather one of outcomes. And pollution can be a moral crime but attacking trade is not usually a good way to go after it. Tax the pollution, not the trade.