(** The [paradox] tactic can be called as a shortcut to use the paradox. *)
Ltac paradox h :=
  unshelve (refine ((fun h => _) (paradox _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ))).

(* Specifications: *)
Theorem paradox : forall F:U1, F.
Lemma strength: forall A (P:A->Prop), M(forall x:A,P x) -> forall x:A,M(P x).