dyn pacifist(X). default quakers_are_pacifists(X): pacifist(X) <- quaker(X). default pro_defense_people_are_not_pacifists(X) : n(pacifist(X)) <- pro_def(X). default rupublicans_are_pro_defence(X): pro_def(X) <- republican(X). constraint not quakers_are_pacifists(X) <- republican(X). constraint not rupublicans_are_pro_defence(X) <- quaker(X). fact quaker(dick). fact republican(dick). fact republican(ron). fact quaker(george).