Whether we agree with the Greek poet that ‘Sometimes it is sweet to be mad,’ or with Plato that ‘A man sound in mind knocks in vain at the doors of poetry,’ or with Aristotle that ‘No great intellect has been without a touch of madness,’ only a mind that is deeply stirred can utter something noble and beyond the powers of others.

Seneca (See also: Alain de Botton focusing on Seneca in the A Guide to Happiness series)