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This article was published exclusively online in the Christian Research Journal, Volume 48, number 04 (2025).
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Whenever I am asked which of Aristotle’s books is the most necessary to read and the most relevant to today, I always answer, Nicomachean Ethics. Alongside Plato’s Republic, Aristotle’s Ethics has been responsible for forming the Western world’s sense of virtue — particularly courage, self-control, wisdom, and justice — and teaching us how one is to live and grow as a moral agent.
Before defining the nature and function of virtue, Aristotle pauses to do what he does in nearly all his books: identify the proper end (telos in Greek) of virtue, which, in this case, is equivalent to the chief end, or good, of man. For Aristotle, that end should be something achievable by all people no matter their trade or situation in life. It should also be something that cannot be taken away by others and that “is always desirable in itself and never for the sake of something else.” That something Aristotle identifies as happiness (eudaimonia in Greek: “well-being” or “good-spirited”): “for this we choose always for itself and never for the sake of something else, but honour, pleasure, reason, and every virtue we choose indeed for themselves…but we choose them also for the sake of happiness, judging that by means of them we shall be happy” (Nicomachean Ethics, Book I, Chapter 7; translator: W. D. Ross).
Virtue as Habit
If, then, happiness is the chief end — the universal good — what virtue will best allow us to achieve it? Aristotle identifies two types of virtue, intellectual and moral, with the first being learned through education and the second being acquired by habit. It is the second type of virtue that Aristotle focuses on for most of the Ethics, but he makes it clear that both types are gained through human effort and training. Although Aristotle was a scientist who explored and classified the unchanging laws of nature, when it came to virtue, he knew that he was dealing with something that was, quite literally, unnatural.
Unlike nature, which follows laws over which it has no control, man chooses whether he will pursue a life of virtue or vice:
none of the moral virtues arises in us by nature; for nothing that exists by nature can form a habit contrary to its nature. For instance the stone which by nature moves downwards cannot be habituated to move upwards, not even if one tries to train it by throwing it up ten thousand times; nor can fire be habituated to move downwards, nor can anything else that by nature behaves in one way be trained to behave in another….the virtues we get by first exercising them, as also happens in the case of the arts as well. For the things we have to learn before we can do them, we learn by doing them, e.g., men become builders by building and lyre-players by playing the lyre; so too we become just by doing just acts, temperate by doing temperate acts, brave by doing brave acts. (NE II.1)
Stones and fire have no choice but to fall toward the center and move away from the center. Only man possesses the ability to resist the force of nature and move in a different direction: either toward or away from goodness and virtue.
A just man is one who acts in a just manner, but he can become a just man only by habitually choosing to make just decisions and perform just deeds. Nature may endow us with physical strength or an aptitude for playing the lyre, but we can transform that endowment or aptitude into the virtue of courage or the skill of lyre-playing only by exercising that virtue or skill diligently until it becomes a habit, a part of who we are. Being a virtuous man and doing virtuous actions are self-reinforcing activities: “by abstaining from pleasures we become temperate, and it is when we have become so that we are most able to abstain from them; and similarly too in the case of courage; for by being habituated to despise things that are terrible and to stand our ground against them we become brave, and it is when we have become so that we shall be most able to stand our ground against them” (NE II.2).
This self-reinforcing cycle of virtue marks the polar opposite of a vicious circle, though it can become that if we allow vicious choices and actions to slowly transform us into vicious people. A true education in virtue must begin when one is young by training the child to feel pleasure when he acts virtuously and pain when he acts viciously. In this vital detail, Aristotle agrees fully with what his mentor Plato taught in Republic and Laws: “we ought to have been brought up in a particular way from our very youth, as Plato says, so as both to delight in and to be pained by the things that we ought; for this is the right education” (NE II.3). For Aristotle, virtue is built up by habit, but it finds its telos in the formation of a certain state of character that, having been properly trained and habituated, naturally chooses virtue over vice and feels proper pleasure at the choice.
C.S. Lewis’s Aristotelian Vision of Virtue
Here is how C. S. Lewis expresses and explains the same point in Christian terms in Book III, Chapter 2 of Mere Christianity (1952):
a man who perseveres in doing just actions gets in the end a certain quality of character. Now it is that quality rather than the particular actions which we mean when we talk of “virtue”….We might think that, provided you did the right thing, it did not matter how or why you did it — whether you did it willingly or unwillingly, sulkily or cheerfully, through fear of public opinion or for its own sake. But the truth is that right actions done for the wrong reason do not help to build the internal quality or character called a “virtue,” and it is this quality or character that really matters….We might think that God wanted simply obedience to a set of rules: whereas He really wants people of a particular sort.
When the prophet Samuel cannot understand why God does not choose the tall and powerful elder son of Jesse as his anointed ruler, God explains to him that “the Lord seeth not as man seeth; for man looketh on the outward appearance, but the Lord looketh on the heart” (1 Samuel 16:7; KJV throughout).
It is the heart, Lewis explains, that God is most concerned with: not the heart as a source of feeling and emotion but as the center of the will. God wants certain kinds of people who will do virtuous deeds, not people who act virtuously for show while their heart is far away from God. But the only way the heart can become properly focused and attuned to virtue is by performing the right actions in the right way for the right motives. When we obey God, that obedience shapes our hearts in the same way that virtuous behaviors do — when they are done for their own sake rather than for reward or applause.
Lewis, like myself, was a firm Christian Platonist, and yet he understood, and I wholeheartedly agree with him, that when it comes to the subject of virtue, Aristotle is an even better guide for the Christian than Plato. Indeed, throughout Book III of Mere Christianity, which is titled “Christian Behaviour,” and which concerns itself with living the Christian life, Lewis relies as much on Aristotle — particularly as filtered through Aquinas and Dante — as he does on the Bible. He does so because, to put the matter boldly and unapologetically, Aristotle got it right! And he got something else right, too.
Aristotle on Moral Agency
As much an influence on Christian virtue as he was on legal thinking in the west, Aristotle defines with acute ethical clarity and keen psychological insight the precise nature of moral agency. For a human agent to perform an action of true virtue, he “must have knowledge, secondly he must choose the acts, and choose them for their own sakes, and thirdly his action must proceed from a firm and unchangeable character” (NE II.4). To paraphrase James 1:22, a moral agent must be both a hearer and a doer of virtue; he must understand fully the nature of his choice and then put that choice into action. In fact, Aristotle, somewhat sarcastically, compares philosophers who think they will become virtuous merely by studying virtue to “patients who listen attentively to their doctors, but do none of the things they are ordered to do” (NE II.4). Let us not forget James’s sobering comparison of non-doing hearers to demons: “Thou believest that there is one God; thou doest well: the devils also believe, and tremble” (James 2:19).
“God is not mocked,” warns Paul in Galatians 6:7, “for whatsoever a man soweth, that shall he also reap.” For Aristotle, as for the Bible, the manner in which a person does something (the means) is as important as the end. Virtue is a complicated thing that calls for intellectual, emotional, and spiritual discernment of a high order. It is easy, writes Aristotle, to “give or spend money; but to do this to the right person, to the right extent, at the right time, with the right motive, and in the right way, that is not for every one, nor is it easy; wherefore goodness is both rare and laudable and noble” (NE II.9).
We who live on this side of Aristotle and Jesus may consider this statement to be an obvious one. But it was not obvious until Aristotle stated it, and it lacked the power to change the world until Jesus preached its proper use in the Sermon on the Mount (Matthew 5–7) and exposed its misuse by the hypocritical scribes and Pharisees (Matthew 23). Attitudes matter as much as words; motives matter as much as deeds. Whether we act in ignorance or with knowledge, in the heat of passion or after cold calculation, matters as much to God as it does to a human judge. Moral agency is a heavy burden to bear and should not be taken lightly.
As an ethicist of the highest order, Aristotle taught Greece, then Europe, and then the world to attend carefully to whether the deeds of people accused of misconduct were committed voluntarily or involuntarily, freely or as a result of compulsion. He taught us the right questions to ask and the right circumstances to take into account. A modern Supreme Court judge could speak these words, and they would not seem out of place: “Acting by reason of ignorance seems also to be different from acting in ignorance; for the man who is drunk or in a rage is thought to act as a result not of ignorance but of one of the causes mentioned, yet not knowingly but in ignorance” (NE III.1). The drunk driver who kills someone in an accident did not do so voluntarily, but he did choose to drink and drive and that makes him a responsible agent, even if it was the alcohol that impaired his senses and caused him to swerve, unwittingly, into another car.
Aristotle and Lewis on How Our Choices Shape Our Character
Carefully and systematically, as if he were cataloguing every variety of a plant or animal species, Aristotle works his way through various “cases” in which ignorance does or does not release a person from moral culpability. Along the way, he makes an incisive distinction between a wish and a choice, and another between a choice and an opinion, that have both moral and legal implications. Wishes, he explains, are related to ends, while choices are related to means. For example, “we wish to be healthy, but we choose the acts which will make us healthy, and we wish to be happy and say we do, but we cannot well say we choose to be so; for, in general, choice seems to relate to the things that are in our own power” (NE III.2). While wishes can transport us to lands of impossibility, choices rest in our own world of possibilities.
It is the same with choices and opinions. Since opinions, too, can be possible or impossible, they involve issues of right and wrong, truth and falsehood. Not so choice, which involves issues of good and bad, virtue and vice: “by choosing what is good or bad we are men of a certain character, which we are not by holding certain opinions” (NE III.2). It is the choices we make, not the wishes we imagine or the opinions we toy with, that shape our character.
Or, to quote Lewis again, who does not have to work hard to take Aristotle’s meditations on virtue, choice, and character up a notch into the fuller revelation of Christ and the New Testament:
every time you make a choice you are turning the central part of you, the part of you that chooses, into something a little different from what it was before. And taking your life as a whole, with all your innumerable choices, all your life long you are slowly turning this central thing either into a heavenly creature or into a hellish creature: either into a creature that is in harmony with God, and with other creatures, and with itself, or else into one that is in a state of war and hatred with God, and with its fellow-creatures, and with itself. To be the one kind of creature is heaven: that is, it is joy and peace and knowledge and power. To be the other means madness, horror, idiocy, rage, impotence, and eternal loneliness. (Mere Christianity, III.4)
Each of us at each moment is progressing to the one state or the other. Aristotle did not develop a doctrine of heaven and hell, but Lewis’s extrapolation of what a virtuous or vicious state of character might look like when drawn out to eternity is true to Aristotle’s ethical and psychological vision.
For Aristotle and Lewis alike, virtue and vice are not things that we do, but creatures that we become. Whether or not Aristotle, had he met Lewis, would have accepted heaven and hell as destinations, he would certainly have recognized them as processes.
Louis Markos, Professor of English and Scholar in Residence at Houston Christian University, holds the Robert H. Ray Chair in Humanities. His 30 books include From Achilles to Christ: Why Christians Should Read the Pagan Classics (IVP Academic, 2007) and From Plato to Christ: How Platonic Thought Shaped the Christian Faith (IVP Academic, 2021).
This excerpt, slightly modified, is taken from chapter 12 of From Aristotle to Christ: How Aristotelian Thought Clarified the Christian Faith (IVP Academic, 2025).
