The philosopher Socrates once asked why all men praise liberty but so many neglect to acquire self-discipline. Without the virtue of temperance, he reasoned, none of us can truly become wise or free, as we’re bound to be misled and enslaved by our own passions. It was the Stoic school of philosophy, though, founded a century after Socrates’ death, which turned this simple insight into a whole way of life. Socrates taught that in order to attain wisdom, we must free ourselves from violent passions, such as greed and anger.
Today, although we cherish our freedoms more than ever, we’ve largely forgotten that they’re meaningless without the strength of character to make use of them well. For Stoics, the uncomplaining endurance required in Greek military training provided an obvious means of learning discipline. Perhaps for that reason, many of the greatest philosophers of antiquity were soldiers.