Synthesized answer
The provided passage does not contain information about what questions remain unanswered in the book "Einführung in das mathematische Denken" [1]. The passage only lists the title, author, and page count of the book. Therefore, it is not possible to answer the question based on the given information.
Synthesized from the book passages below. Chat with the book on Feynman for follow-up.
From the book
Title: Einführung in das mathematische Denken : Die Begriffsbildung der modernen Mathematik by Friedrich Waismann, Karl Menger Pages: 168