Avoiding the ethical relativism and providing the preparations of ethical education are among the most important concerns of scholars in the field of ethics. Two theories of i`tibariat and realism about ethical cases of ought to are discussed among Muslim scholars each seeking to overcome the problem of ethical relativism. It seems that attempts for illustrating the ethical cases of ought to and for showing its reference to reality are easier and clearer solution for absolutism in ethics. In this regard, three theories of “necessity by the other”, “necessity with regard to the other” and mental “obligations” have been proposed by contemporary scholars. After explaining these viewpoints, the paper aims at determining the evidences of the ethical cases of “ought to” and “obligationss” as well as the most important theories proposed about this problem. For this purpose, after explaining the mentioned theories and evaluating them, we concluded that attributing the theory of necessity by the other to Dr. Ha’eri Yazdi is incorrect while it is an ethics suggested by “necessity with regard to the other” that is existed between desirability of ethical action and desirability of its result.