If people with unhealthy characters surround us, the first and most crucial step is to escape their presence. ‘A large part of sanity,’ Seneca explains, ‘consists of letting go of those who encourage insanity and getting far away from a companionship that is mutually harmful.’ The second step is to surround ourselves with people who have good characters, even if it’s a tiny group or a single person. That’s because virtuous people can influence us just as strongly as vicious people, but in reverse.