Under the sea of faith

I think the student whose final reflection started with this image might have been thinking of William James, whose Varieties of Religious Experience acknowledges the trouble of classification in religion thus:

Probably a crab would be filled with a sense of personal outrage if it could hear us class it without ado or apology as a crustacean, and thus dispose of it. "I am no such thing," it would say; "I am MYSELF, MYSELF alone."