There is a belief that the Descriptive/Prescriptive dichotomy is the linguistic/conceptual aspect of the Fact/Value dichotomy. The Descriptive/Prescriptive dichotomy means that terms/concepts are generally divided into two categories: evaluative and non-evaluative. Evaluative terms/concepts are free of any factuality and aren’t truth and false apt. In contrast, there are non-evaluative or descriptive terms/concepts which has the feature of narration of external reality and being truth and false apt. Some believe that there are terms/concepts which have the both property of description and prescription at the same time and these terms/concepts, which being called thick ethical, have the ability to reject the Descriptive/Prescriptive dichotomy and followed by that, to collapse of the Fact/Value dichotomy. The Fact/Value dichotomy means that values aren’t real, objective and a genuine feature of the world. In this research we tend to analyze two problems in Hilary Putnam and al-Farabi’s. First the role of the thick ethical terms/concepts in the rejection of the Descriptive/Prescriptive dichotomy and in the following, the rejection of the Fact/Value dichotomy. Second the way of entanglement between Description and Prescription and its relationship with the Fact/Value problem. The importance of this issue is that the realism, rationality, argumentability, and relativism of moral judgments and statements are directly dependent on the solution of this issue. Therefore, it has a fundamental position in moral philosophy and practical wisdom, and other moral issues are influenced by it. The purpose of comparing these two philosophers, despite their mere belief in moral realism, is to show the fundamental difference between them in explaining and interpreting realism; al-Farabi views realism from the perspective of metaphysical realism, while Putnam, in contrast, views morality from the perspective of internal realism and common-sense realism.
