The Religious Answer: God
The light of Heav’n did the earth illumine
When HE shaped human-nature’s acumen.
Temptations HE then placed everywhere,
But HE’ll punish us for being human!
Helpful effort, or love, defines what’s good;
Goodness taken to extreme is called God.
Laziness, or non-love, is but neutral.
Evil, or harm excess, names the Devil.
The Scientific Answer: Duality
Good and evil—you can’t have one without
The other; so, too, with plenty and drought,
Sadness and smile, life and death, night and day,
Sun and flood, give and take, and truth and doubt.
Opposites are just a different view
Of one fundamental phenomenon—
Light, beauty, and goodness are the inverse
Sides of darkness, ugliness, and evil.
Edges dissolve when opposites are balanced—
Time and dimensional space are transcended.
Everything joins, yet remains as it is,
For what “is not” is as great as what “is”.
Each holds within itself the seed of the other—
Yin reaches climax, then retreats in Yang’s favor:
Cyclic movement of rotational symmetry.
Rounded life is the blend of Yin/Yang together.
Strive to maintain a dynamic balance—of light
And dark, hard and soft, Yin and Yang, and wrong and right.
Reality is found not in separate actions,
But in related events blended in twilight.
(I'm taking a rest now.)