The Magician knew Time. And he knew the World was broken. The Light had broken it.
He came upon this knowledge through the Arcane, the world beyond the World. It was only beyond the World that he could find Truth, because the Light had corrupted the Truth of the World.
He knew that, given Time enough, the World would cease to be. He sought to warn those who could stay Its destruction, and ward off the influence of the Light so that the World could persist.
He found The Fool.