Final answer:
Roderick Usher believes in the sentience of all things, including his ancestral home, which he expresses after performing "The Haunted Palace," symbolizing themes of decay and influence of surroundings.
Step-by-step explanation:
The opinion offered by Roderick Usher following his performance of "The Haunted Palace" in Edgar Allan Poe's "The Fall of the House of Usher" reflects his belief in the sentience of all things, including the inanimate. Usher becomes consumed with the idea that the stones of his familial home, and the home itself, possess a consciousness, influenced by the arrangement and the natural decay around them. This belief seems to be an extension of his mental state as he gradually descends into madness, symbolizing the broader themes of decay and the impact of surroundings on individuals in the story.