To desire things impossible is the part of a mad man.
 Marcus Aurelius, Meditations (c. 170 - 180). copy citation

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

Context

“and that those things that are best, are made one for another? And those things that have souls, are better than those that have none? and of those that have, those best that have rational souls? XVI. To desire things impossible is the part of a mad man. But it is a thing impossible, that wicked man should not commit some such things. Neither doth anything happen to any man, which in the ordinary course of nature as natural unto him doth not happen.” source