was the substance the day's meaning — "The implied question, then, would be…"
The implied question, then, would be whether the Bob Hope had somehow become not just the high-point of the day but its actual meaning. That would be pretty appalling.
Context
Addiction's own definition arrived at cold, without a program, in the appalled voice of someone realizing it in real time: not that the drug was the best part of the day, but that it had quietly become the part that made every other part mean anything, and that with it gone nothing is worth anticipating. It is exactly the recognition the Ennet House chapters build toward — the Substance as the secret meaning of the day — reaching Hal with no meeting, no sponsor, and no word for what he's found but "appalling."