It's evident as sun-tan, to the SEERS, who are what they are because they rule themselves.
"Son of Power"
Will Levington Comfort and Zamin Ki Dost
Under certain inexplicable conditions, normal persons who are not SEERS may observe Nature's mental records like pictures cast upon a screen-often like moving pictures.
"The Fairy-Faith in Celtic Countries"
W. Y. Evans Wentz
Only certain persons, medicine-men and SEERS, can see them; and these describe them as thin and shadowy, and, like the Irish Sidhe, as always youthful in appearance.
"The Fairy-Faith in Celtic Countries"
W. Y. Evans Wentz