Evil is known by God not through its own type, but through the type of good.
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic evil God
Date 1274
Language English
Reference
Note Translated by Fathers of the English Dominican Province
Weblink http://www.gutenberg.org/cache/epub/17611/pg17611-images.html

Context

“whereas as a principle of knowledge it has respect to all things known by God, even though they never come to be in time; and to all things that He knows according to their proper type, in so far as they are known by Him in a speculative manner. Reply Obj. 1: Evil is known by God not through its own type, but through the type of good. Evil, therefore, has no idea in God, neither in so far as an idea is an "exemplar" nor as a "type." Reply Obj. 2: God has no practical knowledge, except virtually, of things which neither are, nor will be, nor have been.” source