Purpose and the addition of quantum mechanical phases.

It is sometimes said that nature has a "purpose", in that it seeks to take the path that produces the minimum action. In fact, nature does exactly the opposite. It takes every path, treating them all on equal footing. We simply end up seeing the path with a stationary action, due to the way the quantum mechanical phases add.

When an archer shoots an arrow through the air, the aim is made possible by all the other arrows taking all the other nearby paths, each with essentially the same action. Likewise, when you walk down the street with a certain destination in mind, you're not alone.

When walking, I know that my aim

Is caused by the ghosts with my name.

And although I don't see

Where they walk next to me,

I know they're all there, just the same.