Illich's 1983 Japan talk seems to be in response to McLuhan's 1971 convocation talk where he critiques Illich: https://mcluhan-studies.artsci.utoronto.ca/v1_iss5/1_5art3.h... (The spacing on this document I'm linking is hideous. Excerpts inlined below, paragraph breaks my own)

Both talks center "enterprise" and communication. Thanks Claude for validating my hunch about the late-century subtweet.

> What has happened today is that there is a new hidden ground of all human enterprises, namely a world environment of electric information, and against this new environment the old ground of 19th century hardware—whether at school or factory, whether of bureaucracy or entertainment—stands out as incongruous.

...

> It is this situation that Ivan Illich addresses himself to in Deschooling Society. He is vividly aware of the irrelevance of current curricula, drills and certification. He knows that these can no longer help us relate to the new world, and he frankly appeals to the forms of preliterate, and even prenatal experience as models for the training now needed.

> As Coleridge said "If you wish to acquire a man's knowledge, first start with his ignorance." Illich is unaware—I'll repeat: Illich is ignorant of the new all-inclusive "surround" of electric information which has enveloped man, but it is his instinctive response to this new ground that in some measure validates the figure-image he suggests for the new school. For example, he says "Since most people today live outside industrial societies. Most people today do not experience childhood. In the Andes, you till the soil once you become useful: before that you watch sheep; if you are well nourished you should be useful by 11, and otherwise by 12."

> Illich relates this story: "Recently I was talking to my night-watchman, Marcos, about his 11 year old son who works in a barbershop. I noted in Spanish that his son was still a nino. Marcos answered with a guileless smile, 'Don Ivan, I guess you are right.' I felt guilty for having drawn the curtain of childhood between two sensible persons." What Illich has in mind, although he does not state it, is that childhood was unknown in the Middle Ages and was a renaissance invention that came in with printing, and is ending very rapidly now in the television age...