Slavery is one of the most common metaphors in Seneca’s writing. He talks about people who are slaves to sex and slaves to work. He talks about people who are slaves to their anxiety. He even mentions-—without much self-awareness for such a generally compassionate person—about his fellow slave owners who are slaves to their slaves.So it might seem strange that there was something he said we should be a slave to. As always, this counter-intuitive observation came from one of his favorite thinkers to hate, Epicurus, who said:“If you would enjoy real freedom, you must be the slave of philosophy.”What does Seneca mean to say by quoting that line? It’s not that we should slave away reading endless amounts of books on philosophy. It’s not that we should work ourselves to the bone writing or researching or getting advanced degrees. Seneca talked quite negatively about people who did all of that.He meant that we had to obey philosophy. That is, the words from these wise Stoics weren’t things to just nod our heads to and then move on. Philosophy isn’t something that we are supposed to take the bits and pieces we like from and then generally behave how we like.The Stoic virtues of Justice, Temperance, Courage and Wisdom are not just buzzwords. They should be our masters. We have to follow them. We have to let them dictate our every move and decision. We have to accept that they own us and that when we attempt to go in another direction, we are fugitives. That’s what Seneca meant.There are many things a human being can be a slave to these days. Drugs. Social media. Personal ambition. Money. Whatever. There’s no freedom in any of that. But in obeying timeless principles, the ones with proven superiority and authority? That’s worth surrendering to.Even if that goes against every freedom-loving bone in our bodies.