What does the cryptic crossword clue "Philosopher’s whisper is audible (7)" mean?

The definition is "Philosopher". The wordplay uses a homophone (sounds like). Sounds like (‘is audible’) RUSTLE (‘whisper’). The answer is RUSSELL.

Philosopher’s whisper is audible (7)

Guardian Cryptic #29447 | 19 Down | 2024-07-29 flower