In defense of the rationality of the Ideal Observer Theory

The Ideal Observer Theory is a theory that has a dispositional explanation of moral affairs. According to this theory, to analyze the meaning of moral propositions, acquire moral knowledge, and ontologically explain moral attributes, one can refer to the dispositions of the ideal observer. Roderick Firth has presented the most significant formulation of this theory. He considers a semantic interpretation of the IOT and believes that most of the efforts of philosophers in analyzing the meaning of good are faced with fundamental problems. He tries to provide an intuitive solution for analyzing the meaning of moral propositions by IOT. The characteristics that Firth attributes to the IO are proportional to the semantic function he intends. The main characteristics of this theory and the characteristics of the IO have been criticized by some philosophers. In this article, we have considered the IO as a metaphor for reason, and the ideal observer's dispositions are the same as rational dispositions. By examining some criticisms of this theory, this presupposition makes its semantic and epistemological interpretations reasonable and defensible. However, by applying some changes in the characteristics of the ideal observer, this theory can be more acceptable and defensible.