Tusculan Disputations

It’s your view of things that upsets you

Earliest we can find

This is the earliest source we can find for the idea. Said again in 6 books on our list: Epictetus, Enchiridion (125 CE), Marcus Aurelius, Meditations (c. 175), Michel de Montaigne, Essays (1580), William Shakespeare, Hamlet (1600), Albert Ellis, Reason and Emotion in Psychotherapy (1962) and Aaron T. Beck, Cognitive Therapy of Depression (1979).

1. “The whole cause, then, is in opinion; and this observation applies not to this grief alone, but to every other disorder of the mind”