  This paper shows how internal models for polymorphic lambda calculi arise in
any 2-category with a notion of discreteness. We generalise to a 2-categorical
setting the famous theorem of Peter Freyd saying that there are no sufficiently
(co)complete non-degenerate categories. As a simple corollary, we obtain a
variant of Freyd theorem for categories internal to any tensored category.
Also, with help of introduced concept of an associated category, we prove a
representation theorem relating our internal models with well-studied
fibrational models for polymorphism.
