 Contractualism can thus produce principles that balance the interests of different people against one another, without explicit appeal to aggregation. This is a significant development in moral philosophy, as it enables us to separate arguments against utilitarianism into two classes: arguments against impartiality and arguments against aggregation. Objections in the first class also apply to contractualism, while those in the second class do not. We return to aggregation in  section 8;  and consider one common objection to impartiality in  section 9.  Once contractualism has entered the field, we cannot treat arguments for impartiality as if they were arguments for utilitarianism itself.