In Nicomachean Ethics Bk.1 ch.3 and Bk.2 ch.2 Aristotle makes a number of important points about the method to be pursued in a ethical work of the type on which he is embarking. He warns us against expecting that the discussion of ethical problems will be characterized by the degree of precision that is to be expected in other forms of discussion. What is the reason for saying so? Aristotle's reason for saying that precision beyond a certain degree in not to be expected in ethics is as follows. Firstly, any general account in bound to obscure the conscious of obligation that arise from the varieties of circumstance. Secondly, the particular account will inevitably lack the simplicity which he regards as characteristic of precision. Then how can the probable conclusion which is derived from his method be admited as a ethical principle? Taking notice of the similarity in discussion between Nicomachean Ethics and Topica, I will understand Aristotle's method in the ethical discussion. Since a dialectics begins with endoxa which are probable but not absolutely certain, conclusions of a dialectical syllogism must be of the same character-probable but not certain. Aristotle describe such a endoxic premise in Ethics as 'what is known to us'. It is an accepted meaning which is a generally accepted idea about a ethical judegment. We move from individual cases, beginning with perception, to a grasp of the universal, by means of a process Aristotle calls epagôê. This is usually translated as induction, although not every interpreter thinks that what he has in mind is what we understand as inductive inference. Aristotle describe such a process in Topica as a dialectical syllogism. In a process of epagôêor a dialectical syllogism Aristotle distinguished between qualified endoxon and unqualified endoxon. For there is conflict opinions in a ethical problem. He confirms ethical principle by means of a process of epagôê. As for the acquisition of first principles in ethical judgement, Aristotle appeals to what sounds somewhat like an inductive procedure. Beginning with the perception of particulars, which are "better known to us"(qualified endoxon), and moving through memory and experience, we arrive at knowledge of universals, which are "better known in themselves"(unqualified endoxon).