John Cage composed music which revolved around silence. Other than his well-known 4’33”, which features a pianist playing nothing for that duration, he was fascinated by silence, as well as sound.
Cage famously recounted a story about his visit to an anechoic chamber at Harvard University. An anechoic chamber is one that is designed to trap all sounds made inside it; it is, essentially, the quietest place on earth.
As Cage said in his work Indeterminacy:
I’d never seen this story challenged before, but I was reading a biography of Cage, The Roaring Silence (Amazon.com, Amazon UK), where the author does question this tale. Author David Revill explains that:
It is possible to call into question the strict factuality of the comments attributed to the engineer, Peter Gena [in A John Cage Reader] has confirmed with several doctors that no-one can hear the operation of his or her own nervous system; the circulation of one’s blood remains inaudible unless there is some incipient cardiovascular blockage. Possibly, Cage was hearing tinnitus.
There is another type of structure that approaches the level of silence of an anechoic chamber: an isolation tank. I spent many hours “floating” in an isolation tank back in the 1980s, and you don’t hear anything other than your breathing (especially if you are wearing earplugs), and, perhaps, your heartbeat, if you are not yet relaxed.
Cage clearly did not hear his “nervous system in operation;” he most likely had tinnitus, which can express as a very high sound. It may not have been strong enough to notice in a normal environment, but in the silence of an anechoic room, it would be noticeable. And the low one, of blood in circulation? Perhaps he had some sort of circulatory problem, particularly near one or both of his ears. (There are certainly times when you hear your heart beating, but I think if that was what Cage heard, he would have said so, because he would have recognized the sound.)
I’ve read several books about Cage, and I find it interesting that no one seems to have questioned this experience, at least not in the biographies I’ve read. This is a foundational story about Cage, which explains how he found that absolute silence does not exist. Yet it suffers from the observer’s paradox; without his presence, there would be (nearly) absolute silence, but what Cage found is that humans – other than the deaf – cannot hear total silence.
It’s worth noting that Pauline Olivero’s in Deep Listening: A Composer’s Sound Practice (Amazon.com, Amazon UK) gives a different angle on this story:
John Cage died of a massive stroke just before his 80th birthday. A physician has said that you wouldn’t hear blood pressure the way he described it. There was plaque in the arteries building up and that if someone had taken heed of what he had said, they would have known it was building toward a stroke. That was one thing. The other – the nervous system does not make a twang that you can hear like that either – it was also part of the condition that led to John Cage’s stroke.
This is a bit tenuous. Cage went into that anechoic chamber in 1951, and he died in 1992. So it’s unlikely that the causes of his stroke were audible 40 years before his death. But it does confirm that you simply don’t hear your nervous system and blood as Cage described.
Of course, Cage doesn’t mention that he heard his own breathing, which he also certainly did. He just filtered that out. So, to him, there were actually at least three sounds. Here’s Cage describing his experience: