One of the ways that critics distinguish Browning from other poets of his era is the faith that he had in God and in his faith, which allowed him to dismiss the kind of scientific knowledge that was being discovered at the time and which so greatly troubled Victorian contemporaries such as Arnold and Tennyson, who were so troubled by questions of faith and doubt, as their poems testify. Browning believed that the world in which humans live is a place that was created to be deliberately imprefect and therefore evil and doubt could exist on earth. What was important for Browning, however, was that the human soul was immortal and heaven was perfect, so that humans will eventually reach a perfect world when they reach heaven. This allowed him, ostebsibly at least, to ignore many of the scientific discoveries of the time, such as Darwinism, which caused such problems. This is something that is captured in a famous quote from one of his poems, entitled "Pippa Passes," that is used by many to define Browning's optimism:
God's in his heaven--
All's right with the world!
However, although these lines can be clearly seen to emerge from Browning's religious philosophy of the perfection of heaven that gives humanity hope as it is contemplated from the perspective of an imperfect world, other critics have questioned Browning's apparent assurance by looking at the existence of evil in his work, and particularly in "Pippa Passes" itself, where these words are affirmed by the protagonist who experiences massive suffering. Some argue that Browning's convictions are not borne out by the existence of such evil in his work, and question whether he, like his contemporaries, was also subject to the same issues of doubt and lack of faith.