This is a story about ethics and economics, winners and losers, and the philosophical muddle on both ends of the political spectrum, as told through two of the hot-button issues of the 2016 U.S. presidential race: the minimum wage and free trade.

Start with an unpopular but irrefutable fact: Raising the minimum wage to $15 an hour, as some states are doing, will create both winners and losers. The winners will be workers who get paid more, of course. The losers will be low-skilled workers who don't get paid at all, because employers couldn't afford to keep them on.

Should you care that a measure intended to make people better off will actually make some worse off? That's a deep question that has exercised such greats as John Stuart Mill, Vilfredo Pareto, and John Rawls. Before you answer it, though, please consider the case of free trade, which involves a similar conundrum. Like raising the wage floor, lowering barriers to cheap foreign imports makes a lot of Americans better off (by cutting the cost of baby clothes, toys, televisions, etc.) while undeniably hurting others (by closing down their factories).