Virtue alone is happiness, and vice is unhappiness.
 Marcus Aurelius, Meditations (c. 170 - 180). copy citation

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Author Marcus Aurelius
Source Meditations
Topic unhappiness happiness
Date c. 170 - 180
Language English
Reference
Note Translated by Meric Casaubon
Weblink https://en.wikisource.org/wiki/Marcus_Aurelius_Antoninus_-_His_Meditatio...

Context

“Ideas and inferences artificially produced by deduction or the like were tested by this 'holding perception.' Of the Ethical application I have already spoken. The highest good was the virtuous life. Virtue alone is happiness, and vice is unhappiness. Carrying this theory to its extreme, the Stoic said that there could be no gradations between virtue and vice, though of course each has its special manifestations. Moreover, nothing is good but virtue, and nothing but vice is bad.” source