+-x= +-x= +-x= +-x= +-x= +-x= +-x= +-x=

Consider the class of all classes that are not members of themselves. Is it a member of itself?

While you're pondering this little puzzle, which is called
Russell's Paradox, I'd like to bring your attention to our most recent
exhibition in Archives and Research Collections. It's called “Bertrand
Russell and the Foundations of Mathematics”. Even if you did poorly in
algebra in grade nine and still can't remember the multiplication table, I invite you to look at this exhibition that will be on display until the end of September.

Throughout his life Bertrand Russell wanted to find a field of
inquiry in which knowledge could be shown to be certain. This quest for certainty led him to spend his early career in writing a book on the principles of mathematics. It was a journey of endurance and emotional upheaval. With Alfred North Whitehead he wrote a book in three volumes entitled Principia Mathematica (1910-13) in which he tried to prove that all pure mathematics follows from logical premises and uses only concepts definable in logical terms. On display are manuscripts, letters, books, and medals awarded to Russell for his contribution to mathematics.

By the way, Russell spent ten years trying to find a solution to Russell's Paradox. I look forward to seeing you in our area of the
Library.