Aristotle, Nicomachean Ethics
H. Rackham, Ed.

Nor again must we in all matters alike demand an explanation of the reason why things are what they are; in some cases it is enough if the fact that they are so is satisfactorily established.¹ This is the case with first principles; and the fact is the primary thing—it is a first principle. [21] And principles are studied—some by induction, others by perception, others by some form of habituation, and also others otherwise²; [22] so we must endeavor to arrive at the principles of each kind in their natural manner, and must also be careful to define them correctly, [23] since they are of great importance for the subsequent course of the enquiry. The beginning is admittedly more than half of the whole,³ and throws light at once on many of the questions under investigation.8.

Accordingly we must examine our first principle⁴ not only as a logical conclusion deduced from certain premises but also in the light of the current opinions on the subject. For if a proposition be true, all the facts harmonize with it, but if it is false, it is quickly seen to be discordant with them. [2]

Now things good have been divided into three classes, external goods on the one hand, and goods of the soul and of the body on the other⁵; and of these three kinds of goods, those of the soul we commonly pronounce good in the fullest sense and the highest degree. But it is our actions and the soul's active exercise of its functions⁶ that we posit （as being Happiness）; hence so far as this opinion goes—and it is of long standing, and generally accepted by students of philosophy—it supports the correctness of our definition of Happiness. [3]

It also shows it to be right in declaring the End to consist in certain actions or activities, for thus the End is included among goods of the soul, and not among external goods.⁷ [4]

Again, our definition accords with the description of the happy man as one who ‘lives well’ or ‘does well’; for it has virtually identified happiness with a form of good life or doing well.⁸ [5]

And moreover all the various characteristics that are looked for in happiness are found to belong to the Good as we define it. [6] Some people think happiness is goodness or virtue, others prudence, others a form of wisdom; others again say it is all of these things, or one of them, in combination with pleasure, or accompanied by pleasure as an indispensable adjunct; another school include external prosperity as a concomitant factor. [7] Some of these views have been held by many people and from ancient times, others by a few distinguished men, and neither class is likely to be altogether mistaken; the probability is that their beliefs are at least partly, or indeed mainly, correct. [8]

Now with those who pronounce happiness to be virtue, or some particular virtue, our definition is in agreement; for ‘activity in conformity with virtue’ involves virtue. [9] But no doubt it makes a great difference whether we conceive the Supreme Good to depend on possessing virtue or on displaying it—on disposition, or on the manifestation of a disposition in action. For a man may possess the disposition without its producing any good result,