We don’t need to become emotionless processors of numerical information—just noticing our emotions and taking them into account may often be enough to improve our judgment. Rather than requiring superhuman control over our emotions, we need simply to develop good habits.

So now we have three models of the mind. Plato said that reason ought to be the master, even if philosophers are the only ones who can reach a high level of mastery.9 Hume said that reason is and ought to be the servant of the passions. And Jefferson gives us a third option, in which reason and sentiment are (and ought to be) independent co-rulers,

although Stoicism is a philosophy, it has a significant psychological component. The Stoics realized that a life plagued with negative emotions—including anger, anxiety, fear, grief, and envy—will not be a good life.

Once we put on our analytical hat, we react to emotional appeals differently. We hinder our ability to feel.