So why do we think that our choice of a four dollar shade-grown fair trade artisanal cup of coffee in a reusable mug matters, but what we do with 4,000 dollars in our investment account for our IRA doesn't?
因此，我们为何会认为 购买4美元一杯的公平贸易树荫咖啡， 用可重复使用的马克杯就有意义， 而善用我们的退休金投资账户 里的4000美金， 就没意义呢？