A Caribbean legend tells of the arrival of Christopher Columbus.
The legend says that the indians on the island where Columbus landed could not see his ships approaching. They saw the ripples in the sea, far away, and were struck with wonder at why such disturbances were occurring in the water. After two or three days of these disturbances moving closer to shore, a shaman was finally able to see the ships. The shaman then went back to his people, described what he saw, and from then on, all of the indians on the island could see the ships.
No one could see the enormous Spanish clippers at first, the legend continues, because they had never seen such things before. They recognized the ripples in the sea because they knew and understood the water, but they had no way to conceptualize what was creating the disturbances because they had no previous associations of such things in their minds.
Once the indians had been told about the approaching ships by their shaman, and had the idea set into their minds, they could finally see the ships and would always recognize them as such.