Full Idea
One of the causes of the troubles that beset us is the way our lives are guided by the example of others; instead of being set to rights by reason we're seduced by convention.
Gist of Idea
Trouble in life comes from copying other people, which is following convention instead of reason
Source
Seneca the Younger (Letters from a Stoic [c.60], 123)
Book Reference
Seneca: 'Letters from a Stoic (Selections)', ed/tr. Campbell,Robin [Penguin 1969], p.227
A Reaction
An interesting practical spin and critique of the standard metaethical idea that morality is just convention. If you think morality is convention, presumably your moral duty is to imitate your neighbours. Nice deconstruction.