Among several maddening bits from Robert Gordon's
The Rise and Fall of American Growth a few years back was this passage:
> The most obvious reason why productivity remained high after World War II, despite the end of the military emergency is that technological change does not regress. People do not forget. Once progress is made, no matter under what circumstances, it is permanent.
Robert J. Gordon, The Rise and Fall of American Growth, Chapter 16, p. 550.
Emphasis in original.
The best counterexample is the apocryphal quote, since adopted by many programmers: "When I wrote that passage, there were two who understood it.—God and myself. Now, alas, God alone understands it!"
https://quoteinvestigator.com/2013/09/24/god-knows/>
I've certainly been in that circumstance with my own code multiple times, as well as at organisations which no longer knew why, or how, certain things were done.
And people, cultures, do forget. The whole notion of "lost wisdom" or "forgotten knowdge" is legion (though unfortunately neither seems to have a Wikipedia article yet which I can conveniently cite here).
Psychology has the notion however of a "forgetting curve", based on the work of Hermann Ebbinghaus, and I'm pretty sure that there's a similar notion which applies at a cultural and/or social level:
https://quoteinvestigator.com/2013/09/24/god-knows/>
A related concept, and one that's given me pause for thought for some time, has been what the minimum sufficient level of continuation of cultural knowledge is, especially given the distinction between explicit and tacit knowledge. The former is easy to codify and transmit via text or speech, the latter is hard to express, and requires direct experience, personal training, or otherwise greater-than-verbal or greater-than-textual instruction. "You can't learn to swim from a book" is one expression of this.[1] In a technological society which becomes ever more specialised, at what point is there no longer sufficient transmission of a concept for it to be considered still "remembered"? How many crafts today have only a single practitioner? Perhaps retired?
(I've posted previously about the art of scientific glass-blowing, which seems headed down this forgetting path.)
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Notes:
1. Though of course there are exceptions. Theodor Kaluza taught himself to swim aged thirty from a book: https://en.wikipedia.org/wiki/Theodor_Kaluza#Personal_life>.