Though, re. Wilbur, from Remembering Elizabeth Bishop:
RICHARD WILBUR: The only time that I remember Elizabeth being undelectable, being cross with me, was on the day of a party at John Brinnin's house. When we had taken to the out-of-doors and were having drinks and would soon move on to croquet, Elizabeth took me up on it when I mentioned that we had just been to church. She said something like, "Oh dear, you do go to church, don't you? Are you a Christian?" I said, "Well, yes, going to church, I am likely to be a Christian." Elizabeth said, "Do you believe all those things? You can't believe all those things." I said, "Like most people, I have my days of believing nothing, and I have my days of believing much of it, and some days I believe it all."
Then Elizabeth began mentioning points of Christian doctrine that she thought it intolerable to believe. She said, "No, no, no. You must be honest about this, Dick. You really don't believe all that stuff. You're just like me. Neither of us has any philosophy. It's all description, no philosophy." At that point Elizabeth shifted to talking about herself and lamenting the fact that she didn't have a philosophic adhesive to pull an individual poem and a group of poems together, but she was really quite aggressive at that point. It surprised me because of her bringing up, [from which she] had many Christian associations, cared about many Christian things. and had got [them] into her poems here and there. I think that's what she was left with, the questions, if not the answers, of a person with a religious temperament.
Relevant comparisons: "I shall say what I think - had Shelley lived he would have finally ranged himself with the Christians..."
And: "Melville, as he always does, began to reason of Providence and futurity, and of everything that lies beyond human ken, and informed me that he had "pretty much made up his mind to be annihilated"; but still he does not seem to rest in that anticipation; and, I think, will never rest until he gets hold of a definite belief. It is strange how he persists - and has persisted ever since I knew him, and probably long before - in wondering to-and-fro over these deserts, as dismal and monotonous as the sand hills amid which we were sitting. He can neither believe, nor be comfortable in his unbelief; and he is too honest and courageous not to try to do one or the other. If he were a religious man, he would be one of the most truly religious and reverential; he has a very high and noble nature, and better worth immortality than most of us."
Bishop found her philosophy in description, like Shelley, like Melville--though the latter two loved to editorialize also (nothing wrong with that). And none of the three believed, not on any day at all.