(4.4.1.1) Open book and closed book
The book "Technique to Read Difficult Books" introduces the difference between open books and closed books. An open book is a book that the author does not say his opinion. The author hopes for the readers to think themselves. A closed book is a book that the author has his opinion. The author hopes for the readers to understand and agree with his opinion. Footnote:
The concept "open" comes from "The Open Works" by Umberto Eco, but I did not read it.