Emunah U'Bitachon 1:1

The trait of Emunah, faith, is easy to acquire for one who is calm of spirit. Such a person – an intellectual, who is living in peaceful times and who is free from physical want – he is uplifted, observing both the heights of heaven and the depths of the earth. Yet, he becomes troubled because the world appears before him as an enigmatic riddle. This riddle, wondrous and hidden, seizes his heart and mind! His whole being becomes subsumed by this riddle and his soul pines to know its solution for which he would willingly pass through fire and water! What use is life to him, if this sweet life is completely hidden from him? His soul becomes entrapped, mourning and longing to understand its secret, yet the path is blocked.
This person, though, has not yet found the solution, when he is again troubled. He has seen much of the evidence that clearly proves that the world before him was built with forethought and planning, as if a wise draftsman drew the entire world before it was created, and although he encountered at each step various impediments, his great diligence enabled him to remove each obstacle, one after another. This craftsman saw how wonderful man could be, and he decided that man would not be deserving of the name unless he had specific information about all that populated his world, for without such knowledge there would be no life for man. The craftsman thought and came up with a mechanism which through it all things on earth could become apparent to man, every one in its own form. He placed in man - on his right and his left - two mechanisms which we call "the eyes."
(How much wisdom is contained in the eye! One cannot become sated of it, for in each generation the wise men add to their understanding of the wisdom which is hidden in the construction of the eye, and they have not yet reached the ultimate.)