The whole of human existence is a quest for what we have lost and forgotten. I attempted to express this in my essay, Art and Atheism, referencing art as one way we seek to remember our origins. T.S. Eliot expresses this much better and more poignantly, however, in these lines from Little Gidding of his Four Quartets.
We shall not cease from exploration
And the end of all our exploring
Will be to arrive where we started
And know the place for the first time.
Through the unknown, unremembered gate
When the last of earth left to discover
Is that which was the beginning;
At the source of the longest river
The voice of the hidden waterfall
And the children in the apple-tree
Not known, because not looked for
But heard, half-heard, in the stillness
Between two waves of the sea.