Final answer:
The evidence supporting the House of Usher being supernatural is the unsettling atmosphere and the reflections in the story. However, there is also evidence to support natural explanations for the events.
Step-by-step explanation:
The evidence that supports the idea of the House of Usher being supernatural is the unsettling and eerie atmosphere described in the story. The house is depicted as being in a state of decay, with a pervasive sense of gloom and darkness.
The narrator's description of the house as a "house of mirrors" suggests that there is something supernatural at play, as the reflections intensify the sense of hopelessness and fatalism.
On the other hand, there is also evidence to support the idea that the events in the story can be explained by natural causes. The deteriorating mental and physical state of Roderick Usher and his twin sister can be attributed to psychological and physiological factors.
The strange occurrences and perceptions experienced by the characters can be understood as manifestations of their disturbed mental states rather than supernatural phenomena.