A rich young man kneels in the road and asks: Good teacher, what must I do to inherit eternal life? Christ's first answer is a question: Why do you ask me about what is good? There is one who is good.[1] Every question about the good — the philosophical one, the moral one, the personal one — terminates there. The classical tradition and the Christian tradition agree on this; they differ only in how explicitly they name the One at the end of the road.

I. The one-sentence definition

Thomas Aquinas, following Aristotle, gives the working definition: bonum est quod omnia appetunt — the good is what all things seek.[2]

Read this slowly, because it is not what moderns hear. "Good" is not being defined by how it feels, by who approves of it, or by what someone decided it should be. It is being defined by the universal inclination of every being toward what completes it. An acorn seeks to be an oak. A seed seeks to germinate. A man seeks to flourish as a man. The direction of every appetite of every thing, when you trace it, is the direction of that thing's completion. The good is what every thing, by its nature, is inclined toward.

And therefore: bonum et ens convertuntur — good and being are convertible.[3] Whatever is, insofar as it is, is good. To be is to be good; the two are the same reality, named from different angles. Being is what a thing has; good is what that being is toward.

II. Aristotle's argument

Aristotle opens the Nicomachean Ethics with a line the tradition has never let go of: every art and every inquiry, and similarly every action and choice, seems to aim at some good; hence the good has been well described as that at which all things aim.[4]

He then argues that the good for a thing must be the good proper to that thing. A good knife is a sharp knife — because cutting is what a knife does. A good eye is a seeing eye. What, then, is a good human being? A human being's ergon — its function, its work, the activity characteristic of it as a human — is rational activity in accordance with virtue. The good for a human being, therefore, is activity of the soul according to virtue, sustained over a whole life.[5]

The argument is called the ergon argument. It has been attacked and defended for twenty-four hundred years. What has never been displaced is the move at its heart: if a thing has a characteristic activity, then the good for that thing is the perfection of that activity. If human beings have such an activity, then the good for us is not arbitrary, not chosen, not constructed. It is discovered.

III. Thomas's demolition of the candidates

Thomas takes up the question at ST I-II q.2 — eight articles, each one asking whether happiness (the ultimate human good) consists in some candidate. He goes down the list: wealth, honor, fame, power, bodily goods, pleasure, any good of the soul, any created good. Each is rejected, in turn, with a single kind of argument: the candidate cannot satisfy an infinite desire.

The argument is structurally the same each time. Human beings are made such that any finite good, once attained, does not rest us. We attain the fortune, the fame, the pleasure — and the appetite returns, unsatisfied. The experience is not accidental; it is diagnostic. Our appetites are sized for something no finite good can fill. Therefore, no finite good is the good for us. Happiness — beatitudo, the ultimate good — consists in God alone.[6]

Augustine had said it a thousand years earlier in a sentence the Church has never improved upon: fecisti nos ad te, et inquietum est cor nostrum donec requiescat in te — you have made us for yourself, and our heart is restless until it rests in you.[7]

IV. Evil as privation

If every thing that is, is good insofar as it is, then what is evil? Not a rival substance alongside goodness. Not a thing at all. Evil is privatio boni — the privation of a good that ought to be there.[8]

Blindness is not a third eye. It is the absence of sight in a being that should see. A wound is not a new part of the body. It is a tear in the wholeness the body should have. A moral evil — a lie, a theft, a murder — is not a new moral substance alongside virtue. It is a failure of a power of the soul to be what that power should be.

This is not a minimization of evil. Evil, as privation, is perfectly real. Blindness is as real as sight. A cancer is as real as a healthy cell. But privation has no positive ground of its own; it is intelligible only against the good it lacks. Which is why evil, however vast, can never be metaphysically ultimate. It is parasitic, always, on the good it distorts.

V. The natural law

If there is a good for human beings, and it is discoverable by reason, then the basic shape of right action is discoverable by reason. This is the natural law, and Thomas's famous first principle of it is: bonum est faciendum et prosequendum, et malum vitandum — good is to be done and pursued, and evil avoided.[9]

From this first principle, the tradition derives the precepts of the natural law: preserve human life, transmit and protect it; live in society, render what is due; seek truth, especially about God; and so on. These are not rules imposed on nature. They are the structure of human good made explicit.

John Paul II at Veritatis Splendor §§79–83 develops the corollary the modern mind needs most: there are acts which, of their very nature, can never be ordered to the good — intrinsece malum, intrinsically evil.[10] Direct killing of innocents. Perjury. Blasphemy. Acts that cannot be made good by any intention, by any circumstance, by any outcome. The argument is not that they are usually wrong. It is that the act itself, as described in its moral species, is incompatible with the good of the human person as a human person. Therefore no end, however noble, licitly orders them.

VI. Christ as the Good

The classical argument, on its own, reaches as far as there must be a Good that is not created, toward which every creature is ordered. Scripture gives that Good a name and a face.

At Matthew 19, a rich young man asks Christ about the good. Christ refuses the easy answer and gives a harder one, which is the right one: there is one who is good.[11] The point is not self-effacement — don't call me good. The point is to redirect the young man's question. He is looking for a teaching; he is standing before the Source. The good he seeks is not a rule, not a list. The good he seeks is a Person, who proceeds to tell him: follow me.

At John 14: I am the way, and the truth, and the life.[12] The transcendentals converge at a single subject. The good, the true, the way — they are not separate Beings. They are the one Being, seen from three angles that the human mind can never quite hold together without a face to rest them on. The Incarnation is the face.

VII. Four modern confusions

The good is preference. "Good is whatever I prefer." No — that would make "I prefer what is bad for me" incoherent; it would make a parent who wants her child to stop eating paint a tyrant; it would make the entire category of akrasia (weakness of will, preferring against one's own judgment) disappear. The common sense of moral life presupposes that preferences can be right or wrong against a good that does not consult the preferer.

The good is pleasure. Aristotle dismantles this in NE VII and X. Some pleasures degrade the one pleased; some pains ennoble. The addict's pleasure at his next dose is not good for him, and no one seriously argues it is. Pleasure is a property of goods rightly enjoyed, not the definition of the good.

The good is authenticity. "Be true to yourself." Unexamined, this collapses. If the self to whom I am being true is cruel, cruelty becomes authentic and thereby good — an evident absurdity. The tradition reverses the formula: the good is the measure of the self, not the self the measure of the good. Be true to who you are called to be, which is a self ordered to the Good that is not you.

The good is utility. What is useful is useful for something. A tool is useful for building; building is useful for shelter; shelter is useful for living; and living is useful for — what? The chain terminates, or it does not. If it terminates, there is an ultimate good that is not merely useful but good in itself. If it does not terminate, the chain is an infinite regress with no bottom, and nothing in it is actually useful for anything. Utility presupposes what it cannot ground.

VIII. What to do with this

If you have read this far: three takeaways.

First, nothing will rest you but God. This is not a motto. It is a structural claim about the appetites you already have. Every time a desired thing is obtained and the appetite returns, take the return as data. You were made for something bigger than the thing you just got.

Second, the Good is a Person, not a system. A system will not walk you out of the tomb. A system is not the thing Mary knelt to. A person can ask, and be followed. The reason the Church insists on the personhood of Christ is not piety; it is metaphysics. The Good, to be the Good, must be a someone.

Third, some acts will never be good. Intrinsece malum. This is the hardest teaching the Church holds on this question, and the most useful to a reader in a confused age. There are acts the good of the human person cannot incorporate, in any circumstance, under any intention, for any outcome. Know the list. Hold it. The Church's pastoral voice is tender; her doctrinal voice, on this, is not, and should not be.

Augustine's line, once more, as a close: pondus meum amor meus; eo feror, quocumque feror — my weight is my love; I am carried, wherever I am carried, by it.[13] Know what you love. That is the answer to what is the good? in the voice of a man who learned it the hard way and would not let you learn it any other way.

IX. What to read next

For the metaphysics of which the good is one mode, see The Transcendentals: being, oneness, truth, goodness, and beauty as one reality under four aspects. For truth specifically — the question Pilate asked and the Johannine Christ answered — see What is truth? on this site.

Sources cited

  1. T0 Gospel of Matthew 19:16–17 (Nestle-Aland 28).
  2. T1 Thomas Aquinas, Summa Theologiae I q.5 a.1 (Leonine edition).
  3. T1 Thomas Aquinas, Summa Theologiae I q.5 a.3.
  4. T2 Aristotle, Nicomachean Ethics I.1 (1094a1–3).
  5. T2 Aristotle, Nicomachean Ethics I.7 (1098a16–18).
  6. T1 Thomas Aquinas, Summa Theologiae I-II q.2 a.8.
  7. T1 Augustine, Confessions I.1.1 (CCEL).
  8. T1 Augustine, Enchiridion ch. 11 (CCEL).
  9. T1 Thomas Aquinas, Summa Theologiae I-II q.94 a.2.
  10. T0 John Paul II, Veritatis Splendor §80 (1993).
  11. T0 Gospel of Matthew 19:17 (Nestle-Aland 28).
  12. T0 Gospel of John 14:6 (Nestle-Aland 28).
  13. T1 Augustine, Confessions XIII.9.10 (CCEL).