It is interesting to note the background noise that the childhood seashell experience makes so abundantly clear is present and apparently ignored as background noise-in fact, its absence is so hmmm
disquieting that when exposed to an environment where it is almost within reach of hearing, people run for cover--that's at the Microsoft anechoic chamber where quiet is equal to -20.6, just 4 dB above the current estimate of molecular collision noises. So we apparently can't hear that under "ordinary" conditions, but can't quite prove, and in any event such is masked by sounds from ones own circulation, eye movement, etc.
But that doesn't entire squash the argument that it prevents a signal being heard, as ample experimentation has shown: signal detection actually improves when low level background noise is present. It also seems to me that just as a long period of dark adaptation is needed before one can see a photon, it may be that a similar period of stimulus deprivation may be needed to achieve absolute measure of sensitivity. Now if only one could stop the heart long enough, and make the experience of ultimate quiet less psychologically distressing.... Perhaps an IV cocktail of curare and valium? (Sort of like being intubated because of Covid, and thinking wow, in retrospect those damn masks weren't so bad after all).
In any event, if we take the -8 number you mention and add it to say 125dB as the loudest we can hear without saturation (arguably this is also "felt)--for me, personally, it was a Quicksilver Messenger Concert at a cow palace where I, in all my adolescent bravado, was standing three rows back and they were actually bragging about 125 dB peaks between songs (yep 3 days of tinnitus afterwards--the sound of hair cells dying
), we get what within a couple of bits. All of which is to say there is still wiggle room for the absolute limit of hearing. Granted we may also need to strip Argon from the listening environnment
, but then oxygen becomes a problem so perhaps dropping the temperature becomes necessary.
In any event, it's not me that needs convincing--though I would still prefer measuring in hard biological terms where that threshold is. It's just a lot more difficult number to measure owing to the complexities of self-noise and necessarily stripping away higher order processing from the picture when the same measurements are made in vitro.