MA Thesis Defense: Liz Sato

‘Thomas Reid on the Relationship between Moral Sense and Reason’
Liz Sato (Cal State Long Beach)
08 Jun 2026 •  11:30am–1:30pm  •  MHB–915

Abstract: Thomas Reid (1710–1796) is one of the relatively less-explained figures in the history of early modern philosophy. My thesis illuminates two relevant issues in the Reidian scholarship: Reid’s position in the debate between moral rationalists and moral sentimentalists and his theory of moral motivation.
     Firstly, Reid’s predecessors debated which faculty is responsible for morality. Some philosophers (‘moral rationalists’) hold that reason alone can provide moral standards and make moral judgments. Other philosophers (‘moral sentimentalists’, although this is one form of the view) hold that moral sense is responsible for moral judgments. Scholars acknowledge that Reid is not easily categorized as being in either camp. For while he contended that moral sense is responsible for moral judgments, his view of the relationship between moral sense and reason is unclear. In fact, there is deep disagreement among scholars on this point. Some scholars, such as Cuneo (2013) and Roeser (2009), argue that moral sense is a part of reason. Other scholars, such as Copenhaver (2014), argue that they are two separate faculties. Clarifying the relationship between moral sense and reason in Reid is necessary to understand his position in the debate. If moral sense is a part of reason, does that mean that the judgment of moral sense is a judgment of reason? Or if moral sense and reason are separate faculties, do they both form moral judgments, or is it only one of them? If both faculties form judgments, how do they do so?
     I argue that Reid thought that moral sense and reason are two separate faculties. In support of my argument, firstly, I examine the argument by Cuneo (2013) for the conclusion that Reid deemed moral sense to be a part of reason (call this ‘the incorporated view’). His argument hinges on the thought that both moral sense and practical reason regulate desires and passions. Since we only know our faculties by their operations, the overlap in regulation suggests that moral sense is a part of reason. I claim that his argument does not support the incorporated view because he needs to show that moral sense and reason regulate desires and passions in the same way. Secondly, I present an argument for the view that Reid takes moral sense and reason to be two separate faculties (call this ‘the separated view’). Both faculties form moral judgments but in an incompatible way. The incompatibility indicates that they are two distinct faculties. I note the main objection to this argument, which is based on the faculty of common sense, and eventually reject it based on the two disanalogies between moral sense and common sense. Additionally, I undermine another argument for the incorporated view, which pertains to Reid’s reply to Hume’s challenge to moral rationalism. These points result in the observation that Reid does not fit well with moral rationalism and moral sentimentalism.
     Secondly, I employ the separated view to explore Reid’s theory of moral motivation. There are two competing interpretations: the rationalist and sentimentalist interpretations. The sentimentalists argue that moral approbation, which is a judgment that necessarily accompanies affection and feeling, is a form of moral motivation for Reid. They believe that Reid agrees with Hume on the view that reason alone is inert in motivating action. I maintain that if the separated view is correct, the sentimentalist interpretation cannot stand because it can only be true on the supposition that the incorporated view is true. In rejecting the sentimentalist interpretation, I endorse the rationalist interpretation and hold that the separated view is compatible with it.

Oral defenses are open to the public.

For a draft copy of the thesis in advance, please contact Liz <liz.sato01@student.csulb.edu> directly.