I know Richard Dawkins has already put this across in his many excellent books but sometimes a shortened layman's view is interesting.
To the subject at hand, intuition is at play, say many years ago your forgaging for food and one of your fellow tribesmen spots a berry tree and eats the fruit.
Hours later he's dead, your intuition tells you don't eat those berries. Fair enough, the individuals that have this trait, i.e. intuition, prosper, the ones that don't die.
However say you kill a cow and later that day there is an earthquake, intuition would tell you don't kill cows, bad things happen.
For a prehistoric man it's a short step from there to conclude that something controls the sun rising in the sky and the birds and the bee's.
In the modern scientific age we would look to prove or disprove that the man died from the berries, maybe it was a heart attack after all. The prehistoric man doesn't have that luxury.