This was interesting enough to prompt an investigation. It looks like the idea comes from this letter that he wrote late in life: https://philosophics.blog/202

This was interesting enough to prompt an investigation. It looks like the idea comes from this letter that he wrote late in life: https://philosophics.blog/2021/08/01/the-futility-of-words/ https://philosophics.blog/2021/08/01/the-futility-of-words/ I don't know German so I can't search for the original with any facility.