Reviewing the Moral Cognitivism of Naṣīr al-Dīn al-Ṭūsī

Moral cognitivism is one of the topics of moral philosophy and epistemology of ethics and Naṣīr al-Dīn al-Ṭūsī is among the moral cognitivists because: first, he refers to various ways for knowing the reality such as reason, fame, experience, revelation and intuition; second, he deals with the middle term as a criterion for knowledge; third, he accepts the demonstrability of the rational moral statements; and fourth, he adheres to moral absolutist. Since he is a moral cognitivist and given that all moral cognitivists are considered moral monists, Ṭūsī is also considered a moral monist; it seems, however, that Ṭūsī, in explaining the demonstrability of moral statements, has not proved the real relationship between the granting of divine blessings and the necessity of gratitude, and has come to the conclusion by claiming that this relationship can be considered the result of a causal relationship between moral act and its result; that is, every moral act, such as thanksgiving, causes happiness and perfection of human beings, and the obligation of thanking God shows the causal relationship between gratitude and the resulting happiness for the grateful person. Therefore, if it is asked why thanksgiving is obligatory, the answer is that this thanksgiving is obligatory because it can lead to happiness and perfection.