It may be hard to believe, but human sciences as we know them today didn’t even exist in the first quarter of the 20th century. By the beginning of the 20th century, psychology was making its first steps towards experimenting. Ivan Pavlov, often considered to be the first experimental psychologist, received the Nobel Prize in 1904 for his research on reflexes not in psychology, but in physiology. The theoretical psychological landscape, just at the beginning of the 20th century, was quite barren; even Jung and Adler did not yet come into their full creative powers.
I really enjoyed reading about education in the 20th century! But it seemed to me--and I may have been misinterpreting--that you were saying that even today, there is no reliable body of research into what educational methods are more effective than others. In fact there has been a great deal of such research, done with control groups, replicated reliably. Here is a very readable book that I recommend. (Full disclosure: the primary author is my father. Still, I do recommend the book on its merits.)
I really enjoyed reading about education in the 20th century! But it seemed to me--and I may have been misinterpreting--that you were saying that even today, there is no reliable body of research into what educational methods are more effective than others. In fact there has been a great deal of such research, done with control groups, replicated reliably. Here is a very readable book that I recommend. (Full disclosure: the primary author is my father. Still, I do recommend the book on its merits.)
https://educationdesignsinc.com/book