The contradictions the mind comes up against — these are the only realities: they are the criterion of the real. There is no contradiction in what is imaginary. Contradiction is the test of necessity.
Contradiction experienced to the very depths of the being tears us heart and soul: it is the cross.
When the attention has revealed the contradiction in something on which it has been fixed, a kind of loosening takes place. By persevering in this course we attain detachment.
The demonstrable correlation of opposites is an image of the transcendental correlation of contradictories.
All true good carries with it conditions which are contradictory and as a consequence is impossible. He who keeps his attention really fixed on this impossibility and acts will do what is good. In the same way all truth contains a contradiction. Contradiction is the point of the pyramid.
The word good does not have the same meaning when it is a term of the correlation good-evil as when it describes the very being of God.
The existence of opposite virtues in the souls of the saints: the metaphor of climbing corresponds to this. If I am walking on the side of a mountain I can see first a lake, then, after a few steps, a forest. I have to choose either the lake or the forest. If I want to see both lake and forest at once, I have to climb higher. Except the mountain does not exist. It is made of air. One cannot go up: one must be drawn.
— Simone Weil
Notes from a Room 
‘The sad truth is that man’s real life consists of a complex of inexorable opposites — day and night, birth and death, happiness and misery, good and evil. We are not even sure that one will prevail against the other, that good will overcome evil, or joy defeat pain. Life is a battleground. It always has been, and always will be; and if it were not so, existence would come to an end.’
— Jung, Approaching the Unconscious