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Nicomachean Ethics | Book 6 | Summary



Section 1

This section provides background for Book 6 by defining the different parts of the soul. Aristotle reminds the reader that the soul has two main parts: the part with reason, and the "nonrational" part humans share with animals.

The rational soul, or the reasoned part, can also be divided into two parts. One part is "scientific," helping humans study knowable facts. The other part is "rationally calculating," helping humans deliberate and make decisions.

Section 2

Aristotle begins by examining how people can make good decisions. He names the soul's three capacities—sensory perception, desire, and understanding. These capacities "control action and truth." Sense perception is a capacity humans share with animals, but it is not used as a principle of action.

Desire helps people determine what to pursue and what to avoid, the way thought helps people know whether to assert or deny a statement. Aristotle describes decision as "a deliberative desire." A good decision requires true reasoning and a correct desire. For decisions to be good ones, the desires motivating them need to be aligned with the truth.

Decisions then lead to action. In other words, a decision is the principle behind an action, or the source of an action. Desire, along with "goal-directed reason" pursuing the truth, is the principle behind a decision.

Thoughtful decisions are not effective by themselves. Their goal is to produce good actions. To make the kinds of decisions leading to good actions, humans need understanding, desire, and thought to point them to the truth. "The function of each of the understanding parts" of the soul—or the soul's third capacity, the capacity for understanding—is to get humans closer to truth.

Section 3

The scientific part of the soul deals with five different states. Each state helps the soul comprehend universal truths. The states are "craft, scientific knowledge, prudence, wisdom, and understanding."

Scientific knowledge deals with unchangeable, eternal facts. This type of knowledge can be learned through deduction, the teaching method proceeding from universal principles. Both students and teachers begin from these common universal principles, or "from what is already known" and use the principle to discover or demonstrate new knowledge. To learn science, Aristotle believes, people need to start with its core principles.

Section 4

Craft knowledge involves "true reason concerned with production." Crafts such as building are concerned with how the artisans or producers can create tangible results. With a craft, the "principle is in the producer." The fundamental cause (or principle) is the person who creates the craft, not the "product" or creation. For a craft to come into being, a producer or creator has to make it. This is why production and action are not the same processes.

Section 5

Prudence can be seen in people who deliberate in a "fine" or virtuous way and who make good decisions about "living well" in all areas. Aristotle defines prudence as "a state grasping the truth, involving reason, concerned with action" about what is good or bad for a person. A prudent person's correct understanding of the truth, and their application of reason, leads them to take the best and most appropriate actions for themselves and others. People in positions of responsibility, like household managers and politicians, need prudence to do their jobs. Someone corrupted by vice has an incorrect understanding of the truth and cannot apply prudence. They will not choose the best actions for themselves. Prudence is always a virtue, as opposed to crafts, which can be executed well or poorly. Prudence belongs to the part of the soul involving belief. "It is not only a state involving reason" like the practice of a certain craft; prudence can't be "forgotten" for lack of use—there are always occasions to make prudent choices.

Section 6

Which came first: knowledge or our ability to grasp it? Aristotle categorizes the types of knowledge available to us as scientific, artistic, practical, and philosophical. Artistic and practical knowledge are variable. Scientific and philosophical knowledge require demonstration from first principles, which can be derived only through intuitive reason. Therefore, our ability to grasp knowledge serves as the prime source of all we know.

Section 7

Wisdom combines understanding and scientific knowledge. A wise person should know both the application of scientific principles and the truth behind them. While wisdom requires knowledge of higher learning and universal truths, prudence deals with human concerns. A prudent person applies knowledge to benefit themselves and others, searching for the good "achievable in action." Wisdom also applies to the studies "that are by nature most honorable." Although political and medical science benefit humans greatly, they are not as honorable as the study of the divine.

Section 8

Political science is a type of prudence. People tend to use the term political science to describe civic laws and decrees, but political science can apply to individual as well as community action. Likewise, people use the term prudence to refer to individual decisions, but prudence can apply to legislators, politicians, judges, and heads of households. In fact, anyone who looks out for his own welfare displays a type of prudence. However, prudence takes time to develop, since the "particulars" it involves can be learned only through experience.

Section 9

Deliberation is a type of inquiry essential to making prudent decisions. People do not deliberate about scientific facts, since they already know these facts are true. Nor do people rely on guesswork to deliberate. A guess is made quickly, but deliberation takes time. Deliberation is not belief, either. Someone who has an incorrect belief will not be able to deliberate well. A good deliberator needs true beliefs. In addition, unlike beliefs, which are "already determined" in the mind, deliberation requires coming to a new conclusion the deliberator has not determined yet.

Instead, deliberation requires reason and thought. Good deliberation uses the correct thought process to arrive at the correct conclusion. The best deliberation has the highest good as its goal.

Section 10

Comprehension deals with the same topics prudence does, but comprehension involves thought rather than action. While prudence focuses on which actions are right or wrong, comprehension analyzes "what [people] might be puzzled about." Comprehension helps people use judgment both accurately and "finely," or in the most virtuous way, to interpret correctly whatever confronts them. Since comprehension requires applying true beliefs, all comprehension is "good comprehension." Comprehension resembles learning because it is a process, similar to how learning is the process of acquiring knowledge.

Section 11

Consideration is a state Aristotle calls "the correct judgment of the decent person." A decent person will be more considerate than others will, since decency requires consideration.

After he has discussed each of the virtues of thought, Aristotle describes what they all have in common. The virtues of thought relate to "particulars" or things that can be achieved in action. "Particulars" come at the end of a thought process. Aristotle also calls them "last things." Understanding is unique, since it starts at the beginning of a thought process, with the "unchanging terms that are first"—also called "universals" or general principles. Thinkers need understanding at "beginning and end" of a thought process. Demonstrations require thinkers to start by understanding these unchanging terms. "[Premises] about action" require thinkers to start by understanding "particulars" or more specific principles achieved in action. He adds, "universals are reached from particulars" to explain how the reasoning process of induction, or explaining a general or universal concept through particular specific examples, requires understanding too.

Many virtues of thought, like understanding and consideration, can be acquired as people age. Some people seem to possess these virtues naturally, but they have really achieved them through experience.

Section 12

What use are the virtues of thought, especially prudence and wisdom? Aristotle again poses several "puzzles" or questions to increase the reader's understanding.

Does knowledge of the good really make people any better? Actions, not knowledge, demonstrate character. An excellent person will not need prudence to become good if that person is already performing right actions. People who have not achieved excellence may not need prudence either, since they will rely on the advice of others, like patients who seek medical advice but do not study medicine themselves.

Aristotle argues that wisdom and prudence are valuable on their own. They help form the state of virtue, which is what leads to happiness. They also help humans fulfill their function. Virtue gives humans correct goals, and prudence lets them achieve "the things promoting the [correct] goal."

Will prudence make people's actions any better? Aristotle reminds his readers of a point he made earlier—actions and states are different. People can do just actions without being just, if they act unwillingly, in ignorance, or with the wrong goals in mind. Prudent people also need cleverness, the capacity to act successfully on a decision. Cleverness is not innately good. Vicious people can achieve their goals through cleverness, but their cleverness is "unscrupulous" or lacking moral standards. Prudence requires a combination of cleverness and virtue. Desire for "the best good" must inform the principles of their actions. To answer this puzzle, Aristotle concludes, "we cannot be prudent without being good."

Section 13

Just as prudence and cleverness are related, natural virtue and full virtue are related. Everyone is born with tendencies toward certain virtues, called natural virtues because they are in a person's nature. Nevertheless, no one is born completely virtuous because a person has to understand what virtue is before being completely virtuous. For humans' natural tendencies to be helpful and not harmful, humans need to gain prudence through understanding as they get older. Aristotle compares a naturally virtuous person without full virtue—understanding virtue—to a blind body in motion, tripping and falling without sight.

Aristotle agrees with Socrates that each virtue requires prudence, but he disagrees with Socrates about all virtues being "[instances] of prudence" or examples of prudence. Aristotle's definition of virtue is more specific. He believes virtue is "the state involving the correct reason" or involving prudence—although prudence (or correct reason) is an essential aspect of full virtue, it is not virtue itself.

Natural virtues can be perfected independently from each other. Someone can achieve one natural virtue, like bravery, before achieving another, like temperance. Nevertheless, anyone who wants to achieve full virtue should be prudent. Aristotle emphasizes that prudence "does not control wisdom or the better part of the soul." He compares prudence and wisdom to medical science and health. Medical science aims for health, but it cannot control health perfectly.


The virtues of thought tie together the previous discussions. Until now, Aristotle has referred to "the correct reason." In Book 6, he explains what the correct reason is and how to apply it.

First, he divides the rational soul into two parts he will reference frequently. The scientific side deals in statements that can be proven or demonstrated, like principles in math and physics, which "do not admit of being otherwise." The "rationally calculating" side is the side Aristotle discusses the most in the Nicomachean Ethics. This side helps people deliberate, make decisions, and negotiate in the moral realms of right and wrong.

He returns to the discussion of decision he began in Book 3. Now the reader can focus on decisions through the lens of "goal-directed thought" as well as character. Good living and right action require a thoughtful examination of different options as well as a desire to do right. Virtues of thought help people know the right thing to do; virtues of character help them do it.

Aristotle breaks down five methods for people to realize objective truths. His definitions of the principles of induction and deduction are widely referenced. Deductive reasoning, which begins with a general statement and moves on to a particular conclusion, involves certainty and is used in science to test hypotheses. A syllogism, with two premises leading to a conclusion, is a form of deductive reasoning. Inductive reasoning starts with particular statements and moves on to general or "universal" conclusions. Inductive reasoning involves more uncertainty. It is generally used in science to form hypotheses but not to test them. Aristotle explains that both methods are essential to discovery. Craft knowledge or techne, skill at a profession, is another key part of fulfilling individual function by doing one's job well.

Prudence, understanding, and wisdom are the three most significant methods Aristotle will discuss. The Greek word for prudence is phronesis, or practical wisdom. Prudent people have common sense. They understand how to behave when there are no guidelines, and they can determine the right action in difficult or stressful situations. Aristotle cites people in leadership and organizing positions—politicians, heads of households, and the renowned Greek general Pericles—as models of phronesis. Prudence takes time and experience to master. It is a virtue of the rationally calculating side of the soul.

Intellectual wisdom, the kind cultivated in a classroom, is expressed by the Greek word sophia. From sophia comes the English word philosophy, or love of wisdom. To Aristotle true wisdom means knowing the facts about demonstrable scientific principles and appreciating what they reveal about the wonder of the world. Since science deals with the unchanging principles of the universe, its study will bring humans closer to comprehending the divine.

Ideally, wisdom combines academic knowledge with prudence. Even great scientists may have knowledge that is "extraordinary, amazing, difficult, and divine, but useless." In Sections 8 and 9, Aristotle investigates the practical implications of prudence and wisdom. Prudence involves "particulars" or knowing the best way to act in a certain scenario, even if there is no precedent or clear universal guideline. Human situations need to be handled with more discretion and nuance than scientific proofs do. The right answers are not as clear. In this case, "correct deliberation" becomes critical. As a scientific way to solve a nonscientific problem, deliberation is the cousin of inquiry. The skilled deliberator, like the skilled mathematician, comes to the right conclusion in the right way.

Unlike comprehension, which also leads to a correct conclusion, prudence is "prescriptive"—it lets someone know what to do. The right conclusion reached in the right way still needs to point to the right action. Cleverness is the art of doing the right action well, while consideration ensures the right action will also be the decent one.

Prudence seems to be an essential tool for the good person. However, if virtuous people already have an inner moral compass, why do they need prudence at all? Aristotle admits that wisdom is superior. To explain prudence's role he returns to the distinction between capacities and states. Virtue, as a state, can mentally prepare someone to do right in any circumstance. However, virtue is not a capacity or an action. Only prudence points people to the correct actions or "the things that promote the end." Prudence does not control wisdom, and it is not a natural capacity at birth, but prudence is how morality functions in the messy physical world.

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