Full Idea
The theory of types seems to rule out harmless sets as well as paradoxical ones. If a is an individual and b is a set of individuals, then in type theory we cannot talk about the set {a,b}.
Gist of Idea
The theory of types seems to rule out harmless sets as well as paradoxical ones.
Source
A.George / D.J.Velleman (Philosophies of Mathematics [2002], Ch.3)
Book Reference
George,A/Velleman D.J.: 'Philosophies of Mathematics' [Blackwell 2002], p.47
A Reaction
Since we cheerfully talk about 'Cicero and other Romans', this sounds like a rather disasterous weakness.