This passage sums up exactly the reader's own experience in trying to navigate Part One of the novel. The allusion is deliberate, and gives a clue as to Conrad's purpose for arranging that section as he did. Note that the effect on Mitchell's guest is to be "annihilated mentally," i.e., deprived of the ability to organize and process the information. The result is that he listens "like a tired child to a fairy tale," i.e., he succumbs to trusting an illusory, patently made-up version for the sake of comprehension. The line sums up the novel's theme in which mankind, lost in the bewildering chaos of experience, takes up the dream-ideal in order to live. For my explanation of how Part One functions stylistically to invoke the reader's own dream-ideal in just this way, see .

Note that the fairy tale comes "as if from another world," indicating its departure from reality, and also hinting at universal subjectivity, in which each individual is a separate world.