The seeker had seen most of what existed, and that was what spurred him on his quest. Although he'd found a well of depravity and evil in the world, he'd never found godliness to match it.
So that was what he sought — pure good; pure light.
It took several lifetimes of seeking to find it.
Step after step he trod, and wore through pair after pair of shoes seeking.
Mountain after mountain he climbed, sometimes over and again, and long enough to watch waters wear paths in the rock, crumbling the great landscape to dust.
Generations came and went and lived and died, and he would have to confess when asked that he saw some light in what passed and remained, but the bad in the world so repulsed him that he kept seeking.
One day he traversed a familiar terrain, but when he crested the mountain he'd climbed before, on the horizon pooled like the sun about to rise was light. All of the Light.
The Seeker was euphoric — he'd found it, finally found it! — when the Light whispered into his mind.
"You have found the thing you sought," it told him, "so understand what it is that you were seeking."
"But I have looked for Light as long as I remember anything," the Seeker replied. "Of course I understand it!"
"Why did you pass it hurriedly when it shone not bright enough for you?" the Light queried. "You could only see the evil by its Light, but you did not see the Light as it was — everywhere. And you could not see it when it shined its brightest in you."
"I don't understand," admitted the seeker.
So the Light showed him, and he saw all that was good in existence and all that was not, pooled in separate places — and then saw that the latter was indeed a reflection of the former, as it had ever been.
And then he saw that in order for anyone — many ones; most ones — to see anything clearly, the Light had to dance with the dark. Else its stark unity that wove everything together became blinding.
He could never have noticed the dark without his own Light.