It's in the living

By philosophy, however, Justin does not mean what most moderns mean—an analytical discipline that applies solely to the intellect, a kind of rigorous exercising of pure reason. Justin doubtless places heavy emphasis upon philosophical reasoning, but for him reasoning philosophically means living in a certain way of life. Philosophy for Justin, as it was for Seneca, Epictetus, and Marcus, is practice, an intellectually dense form of living whose justification is its ability to lead people to new life.—One True Life: The Stoics and Early Christians as Rival Traditions, 155