Final answer:
The symbolism in the passage serves to convey themes of alienation, monotony, and decay.
Step-by-step explanation:
The purpose of the symbolism used in this passage is to convey the themes of alienation, monotony, and decay. The evening spread out against the sky like a patient etherized upon a table represents a sense of lifelessness and apathy. The half-deserted streets, muttering retreats, and tedious argument symbolize the empty and monotonous existence of the modern world. These symbols help to create a mood of disillusionment and the overall theme of the poem.
Learn more about Symbolism in T.S. Eliot's poem