This article argues that philosophers and laypeople commonly conceptualize moral truths or justified moral beliefs as discoverable through intuition, argument, or some other purely cognitive or affective process. It then contends that three empirically well-supported theories all predict that this ‘Discovery Model’ of morality plays a substantial role in causing social polarization. The same three theories are then used to argue that an alternative ‘Negotiation Model’ of morality—according to which moral truths are not discovered but instead created by actively negotiating compromises—promises to reduce polarization by fostering a progressive willingness to ‘work across the aisle’ to settle moral issues cooperatively. This article then examines potential methods for normatively evaluating polarization, arguing there are prima facie reasons to favor the Negotiation Model over the Discovery Model based on their hypothesized effects on polarization. Finally, I outline avenues for further empirical and philosophical research.