Full Idea
The happy life seems to be lived in accordance with goodness, and such a life implies seriousness.
Gist of Idea
The happy life is in accordance with goodness, which implies seriousness
Source
Aristotle (Nicomachean Ethics [c.334 BCE], 1177a03)
Book Reference
Aristotle: 'Ethics (Nicomachean)', ed/tr. ThomsonJ A K/TredennickH [Penguin 1976], p.327
A Reaction
There are far more jokes in the talk of Socrates than in the writings of Aristotle. Presumably seriousness is required by anything which turns out to be difficult.