“His conclusion was that things were not always what they appeared to be. The cub’s fear of the unknown was an inherited distrust, and it had now been strengthened by experience. Thenceforth, in the nature of things, he would possess an abiding distrust of appearances. He would have to learn the reality of a thing before he could put his faith into it.”
Jack London – White Fang, Part II, Chapter IV – The wall of the world.