“Without contraries is no progression.”
– William Blake, The Marriage of Heaven and Hell, 1792
“By proving contraries, truth is made manifest.”
– Joseph Smith
11 For it must needs be, that there is an opposition in all things. If not so, …righteousness could not be brought to pass, neither wickedness, neither holiness nor misery, neither good nor bad. Wherefore, all things must needs be a compound in one; wherefore, if it should be one body it must needs remain as dead, having no life neither death, nor corruption nor incorruption, happiness nor misery, neither sense nor insensibility.
15 ….it must needs be that there was an opposition; even the forbidden fruit in opposition to the tree of life; the one being sweet and the other bitter.
16 Wherefore, the Lord God gave unto man that he should act for himself. Wherefore, man could not act for himself save it should be that he was enticed by the one or the other.
– The Book of Mormon, 2 Nephi 2:11, 15-16