Good and evil are relative terms, and degrees of evil are merely the negative aspect of degrees of good.
 Plato, Phaedo. copy citation

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Author Plato
Source Phaedo
Topic evil good
Date
Language English
Reference
Note Translated by Benjamin Jowett
Weblink http://www.gutenberg.org/files/1658/1658-h/1658-h.htm

Context

“And the manner in which he accomplishes this is by permitting evil, or rather degrees of good, which are otherwise called evil. For all progress is good relatively to the past, and yet may be comparatively evil when regarded in the light of the future. Good and evil are relative terms, and degrees of evil are merely the negative aspect of degrees of good. Of the absolute goodness of any finite nature we can form no conception; we are all of us in process of transition from one degree of good or evil to another. The difficulties which are urged about the origin or existence of evil are mere dialectical puzzles, standing in the same relation to Christian philosophy as the puzzles of the Cynics and Megarians to the philosophy of Plato.” source