There is a story of a people that had an ancient tradition whereby all the adults assembled precisely after harvest at a holy site in the woods near their village and performed an ornate dance. This would assure that over the next year crops would thrive, weather would cooperate, trees bear fruit, babies be healthy and mothers alive; everyone knew that performing this rite would guarantee nothing but good.
Over time and displacement they forgot the precise timing of the dance but they knew where to go and the steps of the dance and the words of the incantation.
Over more time no one could be sure of the precise utterances of the prayer, so the dance proceeded with fewer words and more humming.
With the passage of decades they couldn't be sure of the exact holy place, but they were still pretty sure of the steps of the dance.
By modern times, their descendants can only say that there WAS a holy place, there WAS a magic chant, and that some kind of dance was performed, but the knowledge that this happened is all they have left.



In a similar parable, I recall a story about a teacher leading a group of very young students as refugees. As a means of keeping them together in the case that she won't survive to complete her task, she gives the kids a box and tells them that the box contains a vital message that MUST be delivered. Only when they arrive at their destination do they discover that the box is empty.

The Pope is disputing an atheist, and in exasperation tells him (fatuous Italian accent used to boost the humor) "You are like a blind man in a room with no light, searching for a black cat that isn't there!"
Exasperated atheist to the Pope: "NO! YOU are the blind man in the room with no light searching for a black cat that isn't there, but YOU FOUND IT!"