Abstract Reason may influence preference. The preferences of others may influence my preference. These influences may dominate us. If reason dominates our preferences, we may be in bondage to reason and lack freedom. But if reason has no purpose, we are in bondage to desire. This is the paradox of reason. The answer to the paradox is contained in the formulation of a power preference that is the primary explanation of choice, an ultimate preference. The power preference must be a preference that a person has because he or she prefers to have that preference. When that preference is the primary explanation of choice, the power of preference becomes the source of our free agency as our preferred response to reason.