The lie in the soul is a true lie, the corruption of the highest truth, the deception of the highest part of the soul, from which he who is deceived has no power of delivering himself.
 Plato, The Republic. copy citation

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Author Plato
Source The Republic
Topic corruption truth
Date
Language English
Reference
Note Translated by Benjamin Jowett
Weblink http://www.gutenberg.org/files/1497/1497-h/1497-h.htm

Context

“and probably were never purer than at the time of their decay, when their influence over the world was waning. A singular conception which occurs towards the end of the book is the lie in the soul; this is connected with the Platonic and Socratic doctrine that involuntary ignorance is worse than voluntary. The lie in the soul is a true lie, the corruption of the highest truth, the deception of the highest part of the soul, from which he who is deceived has no power of delivering himself. For example, to represent God as false or immoral, or, according to Plato, as deluding men with appearances or as the author of evil; or again, to affirm with Protagoras that 'knowledge is sensation,' or that 'being is becoming,' or with Thrasymachus 'that might is right,' would have been regarded by Plato as a lie of this hateful sort.” source