The australian philospher colin leslie dean points out a source in ZF thus
ZFC for its inconsistency ie the skolem paradox
the separation axiom is impredicative - and leads to inconsistency in
ZFC- is doubly interesting as zermelo introduced it to outlaw the
russell paradox which showed naive set theory to be inconsistent
http://en.wikipedia.org/wiki/Zermelo%E2%80%93Fraenkel_set_theory
3. Axiom schema of specification (also called the axiom schema of
separation or of restricted comprehension): If z is a set, and \phi\! is
any property which may characterize the elements x of z, then there is a
subset y of z containing those x in z which satisfy the property. The
"restriction" to z is necessary to avoid Russell's paradox and its
variant
poincare and russell argued that impredicative statements led to paradox
in mathenmatics
now
the separation axiom of ZFC is impredicative thus we would expect that ZFC
would end in paradox and it does due to the skolem paradox
solomon
fefermanhttp://math.stanford.edu/~feferman/papers/predicativity.pdf
"in ZF the fundamental source of impredicativity is the seperation axiom
which asserts that for each well formed function p(x)of the language ZF
the existence of the set x : x } a ^ p(x) for any set a Since the
formular
p may contain quantifiers ranging over the supposed "totality" of all the
sets this is impredicativity according to the VCP
this impredicativity is given teeth by the axiom of infinity "