Reason alone teaches us to know good and evil. Therefore conscience, which makes us love the one and hate the other, though it is independent of reason, cannot develop without it.
 Jean-Jacques Rousseau, Emile, or On Education (1762). copy citation

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Author Jean-Jacques Rousseau
Source Emile, or On Education
Topic evil love
Date 1762
Language English
Reference
Note Translated by Barbara Foxley
Weblink http://www.gutenberg.org/cache/epub/5427/pg5427-images.html

Context

“All nations who have acknowledged a good and an evil power, have always regarded the evil as inferior to the good; otherwise their opinion would have been absurd. Compare this with the creed of the Savoyard clergyman later on in this book. Reason alone teaches us to know good and evil. Therefore conscience, which makes us love the one and hate the other, though it is independent of reason, cannot develop without it. Before the age of reason we do good or ill without knowing it, and there is no morality in our actions, although there is sometimes in our feeling with regard to other people's actions in relation to ourselves.” source