This article examines Aristotle's method for defining the concept of happiness in his Eudemian and Nicomachean ethics. In particular, the article draws attention to a methodological passage (Eth. Eud. 1.6 1216b26–35), in which he claims that ‘If we start from what is truly yet not clearly spoken, clarity will be won as we make progress’. This expression comes from Plato's Statesman 275a and 281d. Aristotle then seems to adopt the Eleatic stranger's method in two ways to clarify the initial imprecise statement that happiness is the greatest and best of human goods: first, he distinguishes a target object from other similar objects, and second, he refers to appearances as illustrations to clarify more abstract ethical concepts. This analysis illuminates the influence of the later Platonic method on Aristotle's ethics from a new angle.