In moral philosophy and economics there typically is a dichotomy drawn between selfishness and charity or self-interest and altruism. This is the debate in which the protagonists engage throughout most of the novel: Sam argues in favor of self-interest while Laura argues in favor of altruism. These debates drive the plot arc and bring the characters closer to understanding each other’s views.

Adam Smith is the first modern thinker who combined economics and moral philosophy directly. It is from Adam Smith that Roberts—and Sam—advance from the invisible hand to the invisible heart. A major question in the novel is whether free-market capitalism can yield not only wealth or sufficient quality-of-life for most, but also compassion and kindness. One of Sam’s major fears is that he will be seen as heartless and selfish because of his defense of the value of self-interest. The novel argues that both altruism and self-interest can be virtuous, and both have unseen consequences that must be teased out with careful critical thought.

Sam argues early in the novel that self-interest isn’t a moral question but instead a “a fact of life” (77). He explains to Laura the purpose of the exercise in his class where he offers the students money.