A Comparative Study of John Mackey's Error Theory and Tabatabai's Etebariat Theory

 The present article aims at explaining and applying the two theories of metaethical "error" and " credit perceptions" by John Mackie and Allameh Seyyed Mohammad Hosein Tabatabaei. This article's research design is a library method and attempts to discover, analyze, explain and form the implicit and explicit presuppositions of two significant metaethical theories named "error-theory" and " credit perceptions" respectively designed by John Mackie and Seyyed Mohammad Hosein Tabatabaei. Since the language of ethics, the metaphysics of ethics, the rationality of ethics, and the perception of ethics are some of the most suggestive metaethical assumptions, we will analyze these components in the present research. The result of the comparison is that although the point departure between the error and contingent theory is in one of the anthropological foundations of moral knowledge of these two theories – in the contingent theory, the existence and validity of fixed convention perceptions that are rooted in human nature are pointed out, unethical realism in ethical metaphysics, cognitivism in ethical language, ethical realism in ethical rationality and unrealism in ethical knowledge are important commonalities of these two theories.