Synthesized answer
The provided passages do not contain enough information to answer the question about the central thesis of the text "Mysticism and Logic" by Bertrand Russell.
The passages only offer the title, author, and a category of "Mathematics" [Passage 1]. There is no content from the text itself presented, making it impossible to discern the central thesis.
Synthesized from the book passages below. Chat with the book on Feynman for follow-up.
From the book
Title: Mysticism and Logic by Bertrand Russell Categories: Mathematics Pages: 256