Final answer:
The word 'but' in poetry generally indicates a contradiction or signifies a transition, directing the reader from one idea to the next.
Step-by-step explanation:
The word "but" in the first stanza of a poem typically serves to indicate a contradiction or to signify a transition from one thought or idea to another. It's a transition word that signals a shift in the narrative or tone of the poem. For example, Billy Collins's use of 'but' in 'Litany' emphasizes moves in the thought process, connecting previous ideas to new ones and guiding the reader through the changing landscape of the poem's narrative.