“There ain’t no good guys. There ain’t no bad guys. There’s only you and me, and we just disagree.”
HUMAN NATURE….. 
We are both light and darkness. We will always have both these elements in us—- we can never have only one of the elements. And it is precisely this co-existence of polarly contradictory elements that makes us HUMAN… neither god nor devil…. neither angel nor beast….
Unclerave's Wordy Weblog 
The entire Universe is held together by opposing forces of all kinds acting against each other: good and evil, light and dark, heat and cold, heads and tails, protons(+) and electrons(-), etc. If one vanishes the other will vanish with it and the entire Universe will unravel.
Nothing can exist without contradictions.
Roundly profound! — YUR
Truth can’t exist without lies.
You’re on a roll, my friend! — YUR