Bertrand Russell was particularly known for the famous "Russell Paradox", which wrecked havoc on intuitivistic set theory. The basic restatement of the paradox is the following: suppose there is a predicate "x is a set that does not contain itself", does the set that is the extension of that predicate contain itself. To solve this, Russell came up with the incomprehensibly complex [[theory of types]], which was later abandoned in favour of the [[Zermello-Frankel axioms]].