Some minor side notes:
Brownian motion of air molecules excites the hair cells in your cochlea
Your cochlea is filled with a liquid called endolymph, not air.
A hair cell that was triggered by Brownian motion would be useless. All inner hair cells are tuned to certain vibrations in the endolymph that are greater than those caused by Brownian motion.
A hair cell that was triggered by Brownian motion would be useless. All inner hair cells are tuned to certain vibrations in the endolymph that are greater than those caused by Brownian motion.
Brownian motion is motion of air that, considered as vibrations, has a broad range of frequencies in it. Which means that an ear exposed to air experiencing a sufficiently high level of brownian motion will have many or all of its inner hair cells excited. If your statement was correct, humans would not be able to hear white noise, whereas obviously (to any hearing person who has ever been exposed to white noise) we can.
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Please be respectful of other people's admitting ignorance and don't mock them for it, as they're doing a noble thing.