The doctrine of the mean is a central concept in Aristotle’s virtue ethics. According to the doctrine of the mean, virtue is a mean state between extremes of excess and deficiency. Aristotle describes this mean state as an “intermediate relative to us.” To find the mean relative to us is to find the state of character that “correct reason” requires.
Within the scholarly literature, the doctrine of the mean has been subject to wide-ranging interpretations. James Urmson[1] (1973) called it, “at the very least…a substantial doctrine worthy of Aristotle’s genius,” while Rosalind Hursthouse[2] (2006) stated that it was “not only a false doctrine, but a silly one, and hence should not be ascribed to Aristotle.”

The diversity of interpretations is largely due to the ambiguity that Aristotle himself acknowledges in Book VI of the //Nicomachean Ethics[3] where he states that his account is “true, but not at all clear” (EN VI 1138b26).

The Doctrine is Born

Aristotle’s doctrine of the mean is introduced in Book II of the Nicomachean Ethics (II.2.1104a12-26) by way of a medical analogy. Here, Aristotle says that we destroy our strength by training too much or too little. Similarly, when we eat too much or too little, we destroy our health. Excellence of character, like strength and health, is destroyed by excess and deficiency, but preserved by “what is intermediate” (mesotetos).

Core Aspects of the Doctrine

Gottlieb[4] (2009) identifies the three core aspects of the doctrine of the mean. First, virtue, like health, is produced and preserved by avoiding extremes. Second, virtue is a mean relative to us. Third, each virtue is a mean between two vices, one of excess and one of deficiency.

Of the three elements, it is the second – the “mean relative to us” -- that, according to Gottlieb, is most commonly misunderstood. Here, Aristotle does not offer a precise quantitative test to help determine the mean either generally or for specific cases. Indeed, he does not believe that virtue can be captured by rules or universal principles. Rather, the virtuous person uses reason to determine the correct action at the time. This correct action is the “mean relative to us” and is not to be confused with moderation. For example, correct reason may require extreme anger at extreme injuries and slight anger at a trivial offence. According to the doctrine of the mean, moderate anger would be wrong in both instances. Furthermore, there is no "correct" degree of anger to be displayed under all conditions or under all conditions of a particular type.

The Virtuous Person

According to the doctrine of the mean, virtuous individuals act in a way that lies in a mean between extremes, as when a person of courage, when faced with danger, chooses to take the course of action that is neither cowardly nor foolhardy. For the virtuous person, this mean (e.g. courage) is the state in which feelings are neither indulged without restraint nor entirely suppressed. However, such a state does not come naturally. Instead, it requires habitual training and rational control of one's feelings. Through practice, a balanced disposition -- characteristic of the virtuous person -- can eventually be achieved.

The doctrine of the mean also assumes a unity of virtues such that it is impossible for two virtues to conflict with each other. For example, courage never calls for one to act in a way that is unjust.
Annas[5] (2011) is among the virtue ethicists who distinguish between full or perfect virtue and the enkratic or self-controlled. The fully virtuous take the correct action without any struggle against contrary desires. The enkratic, on the other hand, must control a desire or temptation in order to do so. While the enkratic may act “rightly” in doing what is tactful, courageous or just, he fails to act virtuously since he does not experience the correct emotions.

Phronesis

In the Eudemian Ethics, Aristotle describes virtue as a prohairetic state (EE 1227). In Book V of the Eudemian Ethics and Book VI of the Nicomachean Ethics, Aristotle states that the mean at which one should aim is “as the right logos says" (Moss, 2011)[6] . Phronesis (practical wisdom), as described in the Nicomachean Ethics (1106b21-22), provides the logos which helps the virtuous person determine the mean.

One of Aristotle's controversial claims is his belief that it is impossible to hold all of the virtues – bravery, temperance, generosity, magnificence, magnanimity, the virtue concerned with honor on a small scale, mildness, truthfulness, wit, friendliness, and justice – fully without phronesis, and that it is impossible to have phronesis without holding all of the ethical virtues fully (NE VI.13.1144b30-1145a1).

Notes:

The "doctrine of the mean" does not actually correspond with any phrase that appears in either the Eudemian Ethics or Nicomachean Ethics. However, the term is generally accepted as representative of Aristotle's thesis. The term "golden mean" is used in a similar manner.
  1. ^ Urmson, J.O. (1973). Aristotle’s doctrine of the mean. American Philosophical Quarterly, 10(3), 223-230.
  2. ^ Kraut, R. (2006). The Blackwell guide to Aristotle’s Nicomachean Ethics [Kindle edition]. Retrieved from amazon.com
  3. ^ //
    Aristotle. n.d./1999. Nicomachean Ethics (2nd ed.) (T. Irwin, Trans.) [Kindle edition]. Retrieved from amazon.com
  4. ^ Gottlieb, P. (2009). The virtue of Aristotle’s ethics [Kindle edition]. Retrieved from http://amazon.com
  5. ^ Annas, J. (2011). Intelligent virtue [Kindle edition]. Retrieved from http://amazon.com. doi:10.1093/acprof:oso/9780199228782.001.0001
  6. ^ Moss, J. (2011). ‘Virtue makes the goal right': Virtue and phronesis in Aristotle's ethics. Phronesis, 56(3), 204-261. doi:10.1163/156852811X575907