At the back of this tendency there is a most wonderful secret hidden, the depths of which are fathomed by the mystic. The mystic who sees God within and without, both, who recognizes God in unity and in variety both, the mystic realizes that it is the One Who has known Himself to be One, Who does not know of two, Who feels uncomfortable and agitated, and shows a revolt on knowing that "There exists another besides Me." And it is therefore that the birds have the tendency to fight with their own element, and so the same thing one finds among the beasts. Among men, man is the enemy of man, and woman of woman. The rivalry that exists between professions and between people of the same position and between nations shows the same thing, that one principle that the nature of the ego, through every name and form, revolts against another, especially of the same name and form, in some way or other. One may give a thousand reasons for intolerance. They exist too, but the inner reason is one and the same in all aspects of intolerance. The Sufis have called it Kibriyy, which means "vanity," vanity of the One to Whom alone it belongs.