The Key to Happiness
Thomas Aquinas's Summa Theologiae, Part I-II, Question 2

Table of Contents

Picture of <b>Matthew Shea</b><br><small>Assistant Professor of Philosophy, Franciscan University of Steubenville</small>
Matthew Shea
Assistant Professor of Philosophy, Franciscan University of Steubenville
Picture of <b>Brandon Dahm</b><br><small>Associate Professor of Philosophy, Franciscan University of Steubenville</small>
Brandon Dahm
Associate Professor of Philosophy, Franciscan University of Steubenville

Warm-Up: Do You Want to Be Happy?

Is happiness one of your goals in life? This is an easy question, and virtually everyone will answer yes. But what will make you truly happy? What does happiness really consist in? This is a harder question, and not everyone will give the same answer.

Introduction

The concern with happiness is not something new. The thinkers of old also cared and thought a lot about happiness. This includes Thomas Aquinas (1225-1274), a Dominican priest, scholar, and saint who was one of the greatest philosophers and theologians of the medieval period. For Aquinas, happiness is not just something all of us pursue and desire, but our primary purpose in life and our deepest desire. 


The text we will be reading is from Aquinas’s best-known work, the Summa Theologiae (“Summary of Theology,” abbreviated ST). In it, Aquinas combines Christian theology and Aristotelian philosophy into a harmonious synthesis of faith and reason. Our reading is from Part I-II, Question 2, which is a portion of what is sometimes called the “Treatise on Happiness,” consisting of Part I-II, Questions 1-5. The full text of the Summa Theologiae can be found here.

Key Concepts

Final End – The ultimate goal of human life. All of our other goals are chosen for the sake of this final end.

Highest Good – The greatest good for a human being.

Happiness – The final end and highest good of human life. The perfect good that objectively fulfills human nature and subjectively satisfies desire. 

Object of Happiness – The thing in which happiness essentially consists, the attainment of which will make us truly happy.

Happiness Criteria – The conditions that the true object of happiness must satisfy. They are: finality, intrinsic value, purity, internality, authenticity, stability, self-sufficiency, completeness.

Setting the Stage

To understand Aquinas’s account of happiness, we must know something about his views of human nature and human action. He thinks about these things “teleologically,” that is, in terms of ends, goals, and purposes. According to Aquinas, human beings are rational animals: living, bodily individuals with the capacity to reason. Our rational powers include the ability to think and know, which is called the intellect. The intellect naturally aims at truth as its end, goal, and purpose. Our rational powers also include the ability to desire, choose, and love, which is called the will. The will naturally aims at goodness as its end, goal, and purpose. All of our rational and free actions are aimed at some end. Because the will is naturally aimed at goodness, the end in question will be some good, either a real good or a merely apparent good. There is a hierarchy of ends and goods, with some ends being for the sake of further ends and some goods being superior to other goods.

For example, when we are sick we go to doctors so that they can prescribe us medicine; we take medicine so that we can return to being healthy; we stay healthy so that we can do things like work, play, and take care of our families. But the series of further ends and goods cannot go on forever. We must have a single final end and highest good in life that is chosen for its own sake rather than for the sake of something else, and that helps explain why we choose everything else. It must also be something that is good in itself rather than good because of its relation to something else. Medicine cannot be the final end and highest good because we take it only because it brings us health, and it is valuable only as a means to health. Aquinas argues that our final end and highest good is happiness. (For his defense of these claims, see the Summa Theologiae Part I-II, Question 1).

Main Idea

Happiness

When discussing happiness, Aquinas’s usual Latin terms are beatitudo and felicitas, often translated as “happiness,” “beatitude,” or “felicity.” He is not operating with a popular modern notion of happiness: a psychological concept that equates happiness with a mental state or emotion, such as subjective contentment or warm and fuzzy feelings. Instead, he is assuming the classical concept of happiness as a life that is good for a human person, living well and flourishing. Happiness is a deep and lasting state that realizes the human end and good. Contrary to a widespread modern assumption that happiness is purely subjective and relative to each individual, Aquinas maintains that there are objective facts about happiness that are universally true for all human beings, about which we can be correct or mistaken.

For Aquinas, happiness is both objectively fulfilling and subjectively satisfying. It includes the attainment of objective goods that fulfill our natural human powers (for example, health, knowledge, and friendship) and the satisfaction of subjective desires for these goods that we all have by nature. 

Aquinas makes a distinction between perfect happiness and imperfect happiness: happiness in the truest and unqualified sense vs. happiness in a qualified sense. In our reading, Aquinas is thinking about perfect happiness. One might object that this is too idealistic and unrealistic, like thinking about how to achieve “perfect health” or find the “perfect spouse,” and is doomed to fail because it is an impossible goal. Aquinas’s answer is that perfect happiness is possible and is something we all naturally desire.

Aquinas explains that there are two ways to think of happiness: (1) “the notion of the ultimate end”—the general and abstract concept that we have been discussing up till now, and (2) “the thing in which the ultimate end is realized”—the specific and concrete good that makes us happy (see ST I-II, q. 1, a. 7). The latter question is the focus of our reading. What is the object of happiness: the thing in which happiness essentially consists, the attainment of which will make us truly happy? Aquinas examines various candidates, chosen for their popularity and historical pedigree. He arranges them into “external goods”—wealth, honor, fame/glory, and power—and “internal goods”—goods of the body, pleasure, and goods of the soul. Our presentation will change up the order and combine honor, fame, and glory. At the end, Aquinas widens the scope to include any created good whatsoever, so his analysis does not leave out any possible answer. Aquinas’s method for evaluating the candidates is to test them according to a set of happiness criteria: the conditions that the true object of happiness must satisfy. These criteria are crucial to Aquinas’s argument, and we will identify them along the way as we move through the text.

Wealth

The first candidate for the object of happiness that Aquinas considers is wealth – money and possessions.

Article 1

I answer that, It is impossible for man’s happiness to consist in wealth. For wealth is twofold, as the Philosopher [Aristotle] says (Polit. i, 3), viz., natural and artificial. Natural wealth is that which serves man as a remedy for his natural wants, such as food, drink, clothing, carriages, dwellings, and such like; while artificial wealth is that which is not a direct help to nature, as money, but is invented by the art of man, for the convenience of exchange, and as a measure of things salable.

Now it is evident that man’s happiness cannot consist in natural wealth. For wealth of this kind is sought for the sake of something else, viz., as a support of human nature. Consequently, it cannot be man’s last end, rather is it ordained to man as to its end. Wherefore in the order of nature, all such things are below man and made for him, according to Psalm 8: “Thou hast subjected all things under his feet.”

And as to artificial wealth, it is not sought save for the sake of natural wealth, since man would not seek it except because, by its means, he procures for himself the necessaries of life. Consequently, much less can it be considered in the light of the last end. Therefore, it is impossible for happiness, which is the last end of man, to consist in wealth.

In this passage, Aquinas applies two happiness criteria. The first is finality: happiness is an end in itself rather than a means to something else, and the last end toward which all our actions aim. Wealth fails this condition because it is only a means, not an end. We want wealth to acquire other things. Artificial wealth, such as money, is sought for the sake of natural wealth, and natural wealth is sought for the sake of human life. 

The second criterion is intrinsic value: happiness is valuable in itself, for its own sake, and not just because of its relation to something else. Wealth has only instrumental value as a means to other good things, not intrinsic value in its own right.

Power

The next candidate is power, which can be defined as the ability to do things and make things happen, to carry out one’s will, and to control other people.

Article 4

On the contrary, Happiness is the perfect good. But power is most imperfect. For as Boethius says (De Consol. iii), “the power of man cannot relieve the gnawings of care, nor can it avoid the thorny path of anxiety.” And further on: “Think you a man is powerful who is surrounded by attendants, whom he inspires with fear indeed, but whom he fears still more?” Therefore, happiness does not consist in power.

I answer that, It is impossible for happiness to consist in power; and this for two reasons. First because power has the nature of principle, as is stated in [Aristotle’s] Metaph. v, 12, whereas happiness has the nature of last end. Second, because power has relation to good and evil, whereas happiness is man’s proper and perfect good. Wherefore some happiness might consist in the good use of power, which is by virtue, rather than in power itself.

Aquinas employs the criterion of finality again in this argument. Power is only a means that enables us to achieve other things, whereas happiness is an end and an activity. 

He also introduces another happiness criterion: purity — happiness is wholly good and involves no evil. Happiness is the perfect good, and a “perfect good is that which is wholly free from any admixture of evil, just as that which is perfectly white is that which is entirely free from any admixture of black” (Summa Contra Gentiles, Bk. III, Ch. 48). There are two senses of purity used in this passage. The first is purity of condition: it is uncorrupted and untainted by moral or natural evils. Power fails this requirement because it does not prevent all evils, and there are many examples of powerful people who suffer, such as a tyrant who can be anxious and afraid of losing power, can become ill or be killed, or can be lonely without any true friends. The second sense is purity of cause: it cannot be used for evil. Power can be used for good or evil. Some of the most powerful people abuse their power and commit moral atrocities, revealing that power is not identical to happiness.

Honor, Fame, and Glory

Aquinas discusses the next candidates—honor, fame, and glory—separately, but we will lump them together because all of them can be understood as public esteem and respect or being well known and praised.

Article 2

On the contrary, Happiness is in the happy. But honor is not in the honored, but rather in him who honors, and who offers deference to the person honored, as the Philosopher says (Ethic. i, 5). Therefore, happiness does not consist in honor.

I answer that, It is impossible for happiness to consist in honor. For honor is given to a man on account of some excellence in him; and consequently, it is a sign and attestation of the excellence that is in the person honored. Now a man’s excellence is in proportion, especially, to his happiness, which is man’s perfect good; and to its parts, i.e., those goods by which he has a certain share of happiness. And therefore honor can result from happiness, but happiness cannot principally consist therein.

Article 3

On the contrary, Happiness is man’s true good. But it happens that fame or glory is false: for as Boethius says (De Consol. iii), “many owe their renown to the lying reports spread among the people. Can anything be more shameful? For those who receive false fame, must needs blush at their own praise.” Therefore, man’s happiness does not consist in fame or glory. […]

Reply to Objection 3: Fame has no stability; in fact, it is easily ruined by false report. And if sometimes it endures, this is by accident. But happiness endures of itself, and forever.

Aquinas’s arguments employ four happiness criteria. The first is internality: happiness is an “internal principle” — something connected to our intellect and will rather than something completely external and unconnected to anything inside us. Honor, fame, and glory have an external cause and are given by others.

The second criterion is, like before, intrinsic value. Honor, fame, and glory are consequences or effects of the good, not the good itself. More specifically, they are responses to the good in our knowledge, which is accompanied by esteem, respect, praise, etc. Honor, fame, and glory are bestowed on someone because of some good she already has, and this good is what causes her happiness. They themselves do not bring happiness but are a recognition of a person’s already-existing excellence and happiness.

The third criterion is authenticity: happiness is a true good. Its existence and its goodness are an objective reality that is not merely a function of our beliefs, attitudes, practices, etc. Honor, fame, and glory fail this condition because they depend on us and they can be given even when they are not actually deserved. People can be esteemed, respected, praised, and famous for something that is not true of them.

The last criterion that Aquinas uses in this passage is stability: happiness is permanent, secure, unending, and unable to be lost. He maintains that “man naturally desires to hold to the good that he has, and to have the surety of his holding, or else he must of necessity be troubled with the fear of losing it, or with the sorrow of knowing that he will lose it” (Summa Theologiae I-II, q. 5, a. 4). Therefore, to be perfectly happy we must know that our happiness will last. Honor, fame, and glory are unstable and can be lost if popular opinion changes. As celebrities often discover, fame can be fleeting, reputation can be fickle, and one can go from a hero to a villain (and vice versa) quickly and unpredictably.

Woah, We’re Halfway There

Midway through Question 2, Aquinas summarizes why happiness cannot consist in any of the external goods we have examined so far: wealth, power, and honor/fame/glory.

Article 4

Now four general reasons may be given to prove that happiness consists in none of the foregoing external goods. First, because, since happiness is man’s supreme good, it is incompatible with any evil. Now all the foregoing can be found both in good and in evil men. Second, because, since it is the nature of happiness to “satisfy of itself,” as stated in Ethic. i, 7, having gained happiness, man cannot lack any needful good. But after acquiring any one of the foregoing, man may still lack many goods that are necessary to him, for instance, wisdom, bodily health, and such like. Third, because, since happiness is the perfect good, no evil can accrue to anyone therefrom. This cannot be said of the foregoing: for it is written (Eccl 5:12) that “riches” are sometimes “kept to the hurt of the owner”; and the same may be said of the other three. Fourth, because man is ordained to happiness through principles that are in him, since he is ordained thereto naturally. Now the four goods mentioned above are due rather to external causes, and in most cases to fortune, for which reason they are called goods of fortune. Therefore, it is evident that happiness nowise consists in the foregoing.

In this argument, Aquinas repeats two of the previous happiness criteria: purity of condition and of cause (Aquinas’s first reason), and internality (Aquinas’s fourth reason). He also adds two new criteria. One is self-sufficiency (Aquinas’s second reason): happiness is enough by itself to fully satisfy all our desires; or, as he qualifies it, all of our natural desires for things that are objectively good. If we are happy, there will be nothing left for us to desire. Someone with a great amount of wealth, power, and honor/fame/glory could still lack significant goods that human beings naturally desire, such as health, wisdom, virtue, or friendship.

The other new happiness criterion is a third sense of purity: purity of effect (Aquinas’s third reason) – it cannot be the reason bad things happen to us. Wealth, power, and honor/fame/glory can all cause bad things to befall us. As the saying goes, “more money, more problems.” Power can corrupt and can breed envy and challenge. Fame can lead to public scrutiny and criticism. And so on.

Pleasure

In the second half of Question 2, Aquinas turns to internal goods, starting with pleasure or delight: pleasant experience, enjoyment, and having fun. Pleasure can take the form of either a bodily sensation (such as the taste of ice cream) or a mental attitude of taking pleasure in something (such as a job well done).

Article 6

I answer that, […] in every thing, that which pertains to its essence is distinct from its proper accident: thus in man it is one thing that he is a mortal rational animal, and another that he is a risible animal. We must therefore consider that every delight is a proper accident resulting from happiness, or from some part of happiness; since the reason that a man is delighted is that he has some fitting good, either in reality, or in hope, or at least in memory […] Therefore, it is evident that neither is delight, which results from the perfect good, the very essence of happiness, but something resulting therefrom as its proper accident.

The essence of a thing refers to its necessary and essential attributes that make it what it is. Proper accidents are non-essential attributes that naturally flow from a thing’s essence and manifest themselves when everything goes as it should. For example, being a social animal is part of the essence of a gorilla, whereas going gray is a proper accident that all gorillas share but is not something that makes them a gorilla. Rationality is part of the human essence, whereas risibility (the capacity to laugh) is something that stems from rationality but is not a defining characteristic of human nature.

Likewise, Aquinas argues, pleasure is not the essence of happiness but a proper accident of happiness. When we attain our final end and highest good, it will bring us pleasure, but pleasure itself is not the final end and highest good. One sign that Aquinas is right is that when we pursue pleasure apart from the good it follows from, something goes wrong. Think of fast food without nutrition, sex without love, or success without honest effort. Pleasure fails the criterion of finality because it is not an ultimate end that is pursued for its own sake, and the criterion of intrinsic value because it is a consequence or effect of the good, not the good itself. Whereas honor/fame/glory are responses to the good in one’s knowledge, pleasure is a response to the good in one’s affections, sensations, feelings, or attitudes.

Thought Experiment

The Experience Machine

In this passage, Aquinas rejects hedonism: the theory that happiness consists in pleasure as the only thing that is intrinsically good for us. Hedonism is an influential tradition in the history of ethics, with proponents such as Epicurus, Jeremy Bentham, John Stuart Mill, and Henry Sidgwick. It is a more serious contender now than it was in Aquinas’s time, and he might be accused of dismissing it too quickly here. So it is worth considering hedonism more carefully.

A popular argument against hedonism is the Experience Machine thought experiment, which was introduced by the philosopher Robert Nozick in his book Anarchy, State, and Utopia (1974). In this hypothetical scenario, people have the option of plugging into a machine for the rest of their lives that allows them to experience a virtual reality that is designed to be maximally enjoyable, containing all imaginable pleasures and no pain. The question is: Should you plug into the Experience Machine? Would a life in the machine be the happiest life possible?

If hedonism were correct, then it seems the answer must be yes, because living in the Experience Machine is much more pleasant than living in the real world. But Nozick argues that we would and should answer no. There are good reasons why a life in the machine is not the best life for us. Some important things are missing that seem to matter and to be intrinsically valuable, including: (a) reality—we want actual contact with the real world as opposed to living in an illusion; (b) agency—we want to do and achieve certain things, not just have the false experience of doing them; (c) virtue—we want to become virtuous persons, but genuine character development cannot happen in the machine; and (d) relationships—we want real relations with other persons, but in the machine we can interact only with artificial characters or avatars. If this argument is sound, then hedonism fails the happiness criteria of internality, authenticity, self-sufficiency, and completeness, which will be discussed in the next section.

Goods of the Body

Next, Aquinas considers goods of the body and goods of the soul, which are stronger candidates than any of the previous ones. He ultimately concludes that happiness consists in neither. His overall argument has three steps. (1) The whole human being is ordered to something else. Aquinas further supports this claim by zooming in on the two parts of the human being—body and soul—and showing that both are ordered toward something else. (2) The body is ordered to the soul. (3) The soul is ordered to something outside of the individual.

Aquinas begins with goods of the body, which include primarily life (staying alive) and health, but also physical excellences (longevity, strength, speed).

 

Article 5

I answer that, It is impossible for man’s happiness to consist in the goods of the body, and this for two reasons. First, because if a thing be ordained to another as to its end, its last end cannot consist in the preservation of its being. Hence a captain does not intend as a last end the preservation of the ship entrusted to him, since a ship is ordained to something else as its end, viz., to navigation. Now just as the ship is entrusted to the captain that he may steer its course, so man is given over to his will and reason, according to Ecclus. 15:14: “God made man from the beginning and left him in the hand of his own counsel.” Now it is evident that man is ordained to something as his end, since man is not the supreme good. Therefore, the last end of man’s reason and will cannot be the preservation of man’s being.

Second, because, granted [for the sake of argument] that the end of man’s will and reason be the preservation of man’s being, it could not be said that the end of man is some good of the body. For man’s being consists in soul and body; and though the being of the body depends on the soul, yet the being of the human soul depends not on the body, as shown above [ST I, q. 75, a. 2]; and the very body is for the soul, as matter for its form, and the instruments for the man that puts them into motion, that by their means he may do his work. Wherefore all goods of the body are ordained to the goods of the soul, as to their end. Consequently, happiness, which is man’s last end, cannot consist in goods of the body.

Aquinas argues that bodily goods fail to meet two happiness criteria. The first is finality. The preservation of one’s existence cannot be the final end because human beings are ordered to something else as their ultimate end. I myself am not the highest good—that would be an absurdly ego-centric and exaggerated view of my self-worth, effectively making myself equal to God. To put it differently, “surviving isn’t thriving.” Merely staying alive and being healthy is not enough for a flourishing life. Moreover, bodily goods cannot be the highest goods because we are composed of body and soul. The goods of the body exist for the sake of the soul, and the soul is higher than the body. So, a bodily good cannot be the final end.

The second criterion is a new one: completeness – happiness includes all other subordinate goods and lacks no essential goods; it is comprehensive and includes all human goods. Aquinas endorses Boethius’s statement that happiness is “a state made perfect by the aggregation of all good things” (Summa Theologiae I, q. 26, a. 1). Bodily goods fail this requirement because they do not include goods of the soul. The highest parts of our nature—the capacities that make us human—are the rational powers of intellect and will. The goods corresponding to our rational powers (knowledge, freedom, friendship, virtue, beauty) are more valuable than those corresponding to our bodily powers. Thus, a bodily good cannot be the complete and highest good.

Goods of the Soul

At this point, we might assume that the only remaining candidate for the object of happiness is a good of the soul – some positive characteristic of a person’s mind or spirit. This category includes the possession and exercise of the intellectual virtues (intelligence, wisdom), and the moral virtues (justice, courage). But Aquinas rejects this candidate too. To understand why, it is important to keep in mind that a “good of the soul” is something inherent to the person, not something outside the person that is accessible to the soul.

Article 7

I answer that, As stated above [ST I-II, q. 1, a. 8], the end is twofold: namely, the thing itself, which we desire to attain, and the use, namely, the attainment or possession of that thing. If, then, we speak of man’s last end as to the thing itself which we desire as last end, it is impossible for man’s last end to be the soul itself or something belonging to it. Because the soul, considered in itself, is as something existing in potentiality: for it becomes knowing actually from being potentially knowing, and actually virtuous from being potentially virtuous. Now since potentiality is for the sake of actuality as for its fulfillment, that which in itself is in potentiality cannot be the last end. Therefore, the soul itself cannot be its own last end.

In like manner neither can anything belonging to it, whether power, habit, or act. For that good which is the last end is the perfect good fulfilling the desire. Now man’s appetite, otherwise [known as] the will, is for the universal good. And any good inherent to the soul is a participated good, and consequently a portioned good. Therefore, none of them can be man’s last end.

First, Aquinas argues that goods of the soul, like goods of the body, do not satisfy the criterion of finality. Metaphysically speaking, potentiality is ordered to actuality as its end. For example, the potentials inherent to the parts of our visual system (the eyes, optic nerve, visual cortex, etc.) exist so that we can actually see; they are ordered to the activity of seeing as their natural end. Likewise, the potentials inherent to the parts of the soul—the potential of the intellect to know things, the potential of the will to desire and choose things, the potential of the intellect and the will to acquire virtues—are ordered to something else as their end. The highest parts of the soul are aimed at something outside of us: the intellect is aimed at truth, and the will is aimed at goodness. So, the soul itself is not the final end.

Second, Aquinas argues that goods of the soul fail the criterion of self-sufficiency. The highest good cannot be a power, habit, or activity of the soul because any good that inheres in the soul is a limited (“participated”) good, not an unlimited (“universal”) good. But the human will naturally desires an unlimited good. Thus, a limited good of the soul cannot be the highest good that fully satisfies our desires. We will hear more about this shortly because it is central to Aquinas’s next argument.

Connection

Find Your Inner Happiness?

It is common today to hear that happiness can be discovered “inside myself” and that I should strive to find my “inner happiness.” We are sometimes told that “I am enough,” and as long as I am happy with myself then I do not need to depend on anything or anyone else for my happiness. We once came across a fortune cookie with a similar message, which read: “The purpose of life is to know yourself and love yourself and trust yourself and be yourself.” 

Aquinas would say that the attempt to find happiness inside myself or by myself is a recipe for deep unhappiness. I can be happy only by looking outside of myself. As Aquinas puts it, “Happiness itself, since it is a perfection of the soul, is an inherent good of the soul; but that which constitutes happiness, viz., which makes man happy, is something outside his soul” (Article 7, Reply to Objection 3). Happiness does perfect the soul, and we attain happiness through an activity of the soul; but the object of happiness, the thing that makes us happy, is something outside the soul. Our highest powers are intellect and will, and the best activities we can engage in are knowing and loving. We do not just want to know and love ourselves; we want to know and love things beyond ourselves, especially other persons.

In Article 5, Aquinas compares a human person to a ship. The ship itself (like the human body) must be steered by the captain (like the human soul), and the captain must steer the ship toward some destination. Although a good captain knows his ship intimately (self-knowledge) and appreciates its goods while accepting its weaknesses (self-love), the purpose of sailing is not merely to keep the ship afloat or to move around aimlessly just for the sake of moving, but to get somewhere. Likewise, the purpose of human life is not merely to stay alive, think and choose for the sake of thinking and choosing, or even to be virtuous. It is to fulfill one’s destiny. The key question is: What is our final destination? What is the purpose of human life? What are we made for? Aquinas turns to this question next.

Any Created Good

After having rejected so many candidates for the object of happiness, we are left wondering if there is anything that can fit the bill. At the end of Question 2, Aquinas asks if anything in the world can make us happy, whether it be a created person, thing, activity, or experience. His answer is no. Finite goods like the ones we have discussed are real goods, but they are not the greatest goods, and they will not satisfy the deepest longings of the human heart.

Article 8

It is impossible for any created good to constitute man’s happiness. For happiness is the perfect good, which lulls the appetite altogether; else it would not be the last end, if something yet remained to be desired. Now the object of the will, i.e., of man’s appetite, is the universal good; just as the object of the intellect is the universal true. Hence it is evident that naught can lull man’s will save the universal good. This is to be found, not in any creature, but in God alone, because every creature has goodness by participation. Wherefore God alone can satisfy the will of man, according to the words of Psalm 102: “Who satisfieth thy desire with good things.” Therefore, God alone constitutes man’s happiness.

Argument

God Alone Can Make Us Happy

Aquinas’s argument in this passage can be formulated as follows:

Premise 1: Happiness fully satisfies our desires.

Premise 2: Our intellect and will are naturally aimed at unlimited (“universal”) truth and goodness. 

Premise 3: So, we desire unlimited truth and goodness.

Premise 4: So, only unlimited truth and goodness can bring us happiness. 

Premise 5: God alone is unlimited truth and goodness.

Conclusion: Therefore, God alone can bring us happiness.

In premises 1-4, Aquinas applies two happiness criteria: completeness and self-sufficiency. On his account of human nature, our natural desires for truth and goodness will not be satisfied by any incomplete and finite amount, but only by a kind of truth and goodness that is complete and infinite. We do not just want to know some truths and have some goods, but all truth and all goodness.

Premise 5 states a tenet of classical theism—the understanding of God’s nature held by Aquinas and most theistic philosophers historically. According to classical theism, God is Truth Itself, for to know the truth is to know reality or being, and God is Being Itself. God is also Goodness Itself, “the universal fount itself of good” and “the infinite and perfect good” (Article 8, Reply to Objection 1). God is the cause and paradigmatic exemplar of all perfections, including being, truth, and goodness; and all created being, truth, and goodness is a participation in God’s nature. (For more, see Aquinas’s discussion of the divine attributes of perfection, goodness, and truth.)

In the conclusion, Aquinas gives his answer to our question. The true object of happiness is God: “God is the last end of man and of all other things […] For man and other rational creatures attain to their last end by knowing and loving God” (Summa Theologiae I-II, q. 1, a. 8). Knowing and loving are the best activities we can perform, and the best thing we can know and love is the personal God, who is Truth Itself and Goodness Itself. Union with God is our final end and highest good, and the only thing that can bring us the perfect happiness we desire, realizing the two components of happiness—objective goodness and subjective satisfaction—to the highest possible degree.

Summary

According to Thomas Aquinas, happiness is the final end and highest good that all of us seek in life. Finite and imperfect goods such as wealth, power, honor/fame/glory, pleasure, goods of the body, and goods of the soul can make us imperfectly happy, but they cannot make us perfectly happy. The only way we can attain true and perfect happiness is in personal relationship with the infinite and perfect good who is God.

Do It Yourself!

Are You Happy?

Reflect on the following questions: 

Are you truly happy? If so, why? If not, why not? 

What would it take for you to be happy? Is something missing in your life?

Do you agree with Aquinas’s happiness criteria? Which ones do you agree with or disagree with? 

Is it possible for you ever to be happy in this life? If not, is it possible to be happy in the next life?

Want to Learn More?

In our reading, Aquinas does not explicitly say how God is supposed to satisfy all the happiness criteria we have identified. He goes on to argue that they are met only in the state of eternal union with God in the afterlife. For Aquinas, true happiness is a supernatural end (heavenly union with God) that is reached by supernatural means (God’s grace), and it is ultimately a gift of God’s rather than an achievement of ours. If these claims strike us as being too “religious” or “faith based,” we should remember that Aquinas’s method is to use reason, argument, and evidence to answer the big questions of life; so it is worth considering his arguments for these claims too. For his full account of happiness, keep reading the Summa Theologiae, especially Part I-II, Questions 3-5.

Acknowledgements

This work has been adapted from the Summa Theologiae by Thomas Aquinas, translated by Fr. Laurence Shapcote, and made available online by the Aquinas Institute. This work is in the public domain. All images were created using Midjourney.

Citation

Shea, Matthew and Brandon Dahm. 2025. “The Key to Happiness: Thomas Aquinas’s Summa Theologiae, Part I-II, Question 2.”  The Philosophy Teaching Library. Edited by Robert Weston Siscoe, <https://philolibrary.crc.nd.edu/article/key-to-happiness/>.

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Object of Happiness – The thing in which happiness essentially consists, the attainment of which will make us truly happy.

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Key Concept

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Pleasure – Epicurus would have us think about pleasure as coming in two forms: moving and static. Moving pleasures are the type that we experience in the process of satisfying a desire (this coffee tastes amazing!). Static pleasure is the feeling of being satisfied — no longer experiencing need or want (I am feeling so peaceful sitting in the park). Epicurus thinks these static pleasures are the best sort.

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Key Concept

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Key Concept

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Key Concept

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Key Concept

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Key Concept

Metaphysics: the study of what there is. Traditionally, metaphysics is divided into general metaphysics and special metaphysics. The former investigates the general features of reality and asks questions such as ‘What is possible?’. The latter studies particular kinds of being and asks questions such as ‘Does God exist?’ or ‘Is the soul immortal?’.

Key Concept

Reason: the faculty that knows a priori. Kant uses this term in a general sense (the knowing faculty as such) and in a specific sense (the faculty that demands ultimate explanations).

Key Concept

A priori: term denoting propositions that can be known independently from experience. For example, propositions such as ‘All bachelors are unmarried’ or ‘The whole is greater than its parts’ can be known without recourse to any experience.

Key Concept

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Key Concept

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Key Concept

Form (εἶδος / ἰδέα) – Intelligible, immaterial, perfect entities that explain the unity among the many things which share the feature named by the entity (e.g., Beauty, Squareness, Oddness). For example, think of a square. There might be many different squares, but they all share features like having four sides of equal length. So, the Form of Squareness would include all of those features that make something a square.

Key Concept

Guardian – This is the name Plato gives to the ruling class in his ideal city. Think of them as philosopher kings – they have complete control over the organization of the state. The Republic is partially about why Plato thinks they would be needed for an ideal system of government and what they would need to learn to do the job well.

Key Concept

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Key Concept

Soul (ψῡχή) – What Greeks meant by this word is controversial. For now, think of it as the thing that makes you different from a rock or other objects, the thinking and experiencing part of you as well as the part of you that acts and makes decision. You might use the word ‘mind’ or ‘self’ to talk about this.

Key Concept

Virtue – Virtues are the character traits that make a person good. For example, most people consider courage and generosity to be virtues. English-speakers usually reserve the word ‘virtue’ for human beings, but in ancient Greek the word can be more comfortably applied to other beings as well.

Key Concept

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Key Concept

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Key Concept

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Key Concept

Meletus – A poet and citizen of Athens and one of Socrates’ accusers. Amongst other things, Meletus accused Socrates of impiety and corrupting the youth.

Key Concept

Divine Voluntarism – The idea that God is free to determine even the most basic truths. If divine voluntarism is true, then God could have made it so that 2+2=5 or so that cruelty and blasphemy are holy and good.

Key Concept

Euthyphro Dilemma – The question, “Is a thing holy because the gods love it, or do the gods love it because it is holy?” The general idea of a forced choice (or “dilemma”) about the true order of explanation occurs often in philosophy and gets referred to by this term.

Key Concept

Essence – What a thing fundamentally is. A square might be red or blue without changing the fact that it’s a square, but a square must have four sides, so having four sides is part of a square’s essence.

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Definition – The perfect description of a thing. A definition should pick out all and only examples of a thing. For example, ‘bachelor’ might be defined as ‘unmarried man,’ because all unmarried men are bachelors, and only unmarried men are bachelors.

Key Concept

In Disney’s retelling of the Hunchback of Notre Dame, the clergyman Claude Frollo orders the death of many Roma on religious grounds. It is clear, however, that he is really motivated by spite and his unrequited lust for the Romani woman Esmerelda.

Key Concept

Spanish conquistadors were shocked by the scope of ritual human sacrifice among the Aztecs, as hundreds or even thousands of people were sacrificed each year. The Aztecs thought that the sacrifices could repay the sacrifices the gods had made in creating the sun and earth.

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Zeus – The god of sky and thunder in ancient Greek mythology, Zeus was depicted as chief among the gods and called the father of the gods and men.

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Forms – The perfect, divine, and intelligible entities that exist independently of the physical world. They are comprehensible only through reason, not through our senses, and their existence explains the properties of objects in the physical world.

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Recollection – The soul existed prior to birth; during this time it learned everything, and hence all learning is only recalling what we already know.

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Immortality of the Soul – Unlike the body, the soul is not subject to physical death, because it is immortal and indestructible.

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Philosophy – The practice of preparing the soul for death by training it to think and exist independently of the body

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Death – Plato understands this as the soul’s separation from the body

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Human Identity Across Time – Locke’s notion that any human stays the same across time if, and only if, it maintains the same (distinctively human) organizing structure of parts.

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Substance Identity Across Time – Something is the same substance across a segment of time if, and only if, it continuously exists across the relevant segment of time without gaining or losing any of its parts.

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Immaterial Soul – A personal thinking substance without any physical constitution.

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Personal Identity Across Time – Whatever makes someone the numerically same person (i.e., that very person) at different times; according to Locke, it is a relation of first-person consciousness via memory.

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Person – Locke’s forensic definition of person (pertaining to courts of law regarding the justice of praise, blame, reward, or punishment): a thinking, intelligent being, that has reason and reflection, and can consider itself as itself, the same thinking thing in different times and places.

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The Prophet Muhammad is a central figure in Islam.  He is viewed as the last of a long line of prophets, which includes Moses and Jesus. He is responsible for writing the Quran, which was dedicated to him by the angel Gabriel.  His life and sayings are recounted in the Hadith; he is viewed as an exemplary role model of Islamic life and faith.

Key Concept

Exhortation — The method of understanding and interpreting Truth available to the common people. The majority of people take scripture literally and understand truth and right action based upon this understanding. They are persuaded by the vivid imagery of the Quran and the rhetorical exhortations of religious leaders. Averroes takes this to be lowest form of understanding

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Dogmatic Discourse — The method of understanding displayed by those who, through natural ability and habit, are able to have a deeper understanding of the Quran, and of the truths it illuminates. These people know that not all of the scriptures are to be taken literally, and that greater underlying Truths are revealed by interpreting some elements allegorically. Still, they err on the side of dogmatism and literal interpretation whenever uncertainty arises. Averroes associates this way of thinking with Muslim theologians and views this to be the middle level of understanding.     

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Philosophical Inference – The type of understanding associated with philosophical demonstration or argument. This is the highest level of understanding, accomplished by a select few, who have a natural capacity for philosophy and proper philosophical training. 

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Law — The Quran (the central religious text of Islam) and, to a lesser extent, the Hadith (reports of what the prophet Muhammad said and did). Averroes is concerned with explaining how philosophy relates to what Muslims take to be the unerring Truth regarding God and the nature of existence, as they are expressed in Scripture.

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Occasionalism — a theory claiming that God is the only true cause of changes in the world. For example, when you high-five me, you’re not really the cause of the stinging sensation I experience. God is the cause. Your high five is just the occasion on which God causes it.     

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Interactionism — a theory claiming that things in the world can truly cause changes in each other. For example, when you high-five me, you truly cause me to experience a stinging sensation in my hand.

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Substance Dualism — a theory claiming that the mind (or soul) and body are two distinct and very different things.

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Body — what it sounds like! The body is the physical part or aspect of a thing and has characteristics like shape, size, etc.

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Soul — that part or aspect of a thing involving mental aspects of their existence, e.g., thoughts, feelings, decisions, etc. The “soul”, in this sense, is more or less just the mind.

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Causal Interaction — When one thing acts (i.e., itself does something) and in so acting makes another thing change. For example, when you high-five me, you cause me to experience a stinging sensation in my hand.

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God as God – The phrase “God as God” is basically a synonym for “God the subject.” In other words, it refers to God precisely in God’s status as an incomprehensible divine Other.

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Incarnation – The Christian doctrine of the incarnation is the notion that the word of God became fully human in the person of Jesus of Nazareth. It is closely associated with the doctrine of the trinity, which asserts that God the Father, God the Son (Jesus as the word made flesh), and God the Holy Spirit are one God.

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Religious Fanaticism – In Feuerbach’s use of the term, a religious fanatic is someone who is unwaveringly faithful to God as an utterly mysterious superhuman being. They subordinate other things—especially the love of other humans—to submission before this divine other.

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God the Subject – When Feuerbach refers to God as a subject, he is referring to the commonplace religious belief that God is a being who has various attributes, like a loving nature.

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Faith Separates Man From God – Faith separates God from man in this sense: it treats God as a mysterious other, a being radically distinct from us.

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 Faith – Belief in and fidelity to a transcendent divine subject like God.

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Orthodoxy – Orthodoxy refers to “right belief,” and it is concern with identifying heresies and ensuring that people believe and practice correctly.

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Indirect Form of Self-Knowledge – Feuerbach’s view is that religious belief is a naive way of relating to our human nature and its perfections. It is naive or childlike because it treats these as external realities that belong to God. He believes a mature and contemplative person realizes these don’t belong to God, but rather to our species, abstractly conceived.

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Above the Individual Man – The human perfections are “above the individual” insofar as no particular individual ever perfectly realizes them. They are abstractions.

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Divine Trinity – Feuerbach is having fun here. He is using the theological phrasing of the Trinity to talk about human perfections. In calling reason, love, and freedom of the will “divine,” he means they are absolutely good; they are activities whose goodness is intrinsic to their practice or exercise. This isn’t a novel philosophical view. For example, Immanuel Kant argued that autonomy or a good will is the only thing which is unconditionally good.

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Perfections – The end to which a faculty or power is ordered. For example, omniscience would be the perfection of the intellect. Traditionally, God is said to possess all perfections.

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Love – When Feuerbach writes about love, he is referring to unconditional concern for others and the desire for fellowship with them. He is here asserting that love, understood in this sense, is the perfect activity of the affective faculty. In other words, our feelings and passions are fully actualized and engaged in an intrinsically valuable activity when we genuinely love others.

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Infinite – The infinite is whatever can be understood as unbounded or unlimited. Human nature in the abstract is unbounded and unlimited. It is only bounded or limited in its concrete form as it is realized by particular material individuals.

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Higher Consciousness – The sort of consciousness that mature human beings possess, but which other animals do not. It is “higher” than animal consciousness because it involves thinking abstractly about the form or essence of things.

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Science – Feuerbach uses the term science in its classical sense, meaning systematically organized knowledge. Any body of knowledge founded on an understanding of first principles and the essences of things is a science in this sense.

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Popular Sovereignty – The view that a government’s authority to rule comes from the people, making a ruler subject to the will of their citizens.

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The Divine Right of Kings – The theory that kings are chosen by God and thus that political revolt is a rebellion against the will of God.

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Synthesis – The prefix ‘syn-’ means “together,” so a synthesis “brings together” or combines elements of both a thesis and its antithesis.

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Antithesis– An antithesis is the contradiction of a thesis. For example, internationalism could be understood as the antithesis of nationalism.

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Thesis – In Hegelian terms, a thesis can be understood as a position or theory. Examples include any of the “-isms” that we discuss in science, history, and philosophy, such as Darwinism, capitalism, nationalism, etc.

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Progressor’s Temptation – a unique temptation for those making progress in which pride impedes their further progress and leads to backsliding.

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Progressors – those who are not yet expert Stoic practitioners, but who are also aware of the fact that they must change their lives in that direction. They are working on making progress.

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Intellectualism – the philosophical view that our motivations and emotions are all judgments. The reason why you do something, your motivation, is because you believe it’s the right thing to do. The reason why you feel good or bad about something, an emotion, is because you believe that something good or bad happened to you.

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Duties – acts of service, obedience, and respect that we owe to each other. The duties we owe to each other depend on what kind of relationship we have.

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Askeses – exercises of Stoic thought and practice that make the lessons and habits of Stoic philosophy second-nature for Stoic practitioners.

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Externals – things that are not under our control but that are all-too-easily confused with things that should be important to us, like wealth, status, and pleasure. Too many people believe externals like these are necessary for the good life, and the Stoic path is to focus not on these things but rather what is up to us. 

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The Fundamental Division – the division between things that are under our direct control and those that are not. The important lesson is to care only about the things we can control.

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The Greatest Happiness Principle – A principle which says that actions are right insofar as they promote happiness and wrong insofar as they promote unhappiness

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Higher and Lower Pleasures – Types of pleasures that differ in terms of their quality. Things like food and drugs create lower pleasures. Things like intellectual pursuits and doing the right thing create higher forms of pleasure.

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The Doctrine of Swine – An objection that utilitarianism entails that if people would be happy rolling in mud, that’s what would be morally best for them to do, so we should reject the theory.

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Utilitarianism – A normative theory of which actions are right or wrong. Utilitarianism says the right action is that which maximises utility.

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Jeremy Bentham – Considered by some as the father of utilitarianism, Bentham was a moral philosopher and one of John Stuart Mill’s teachers

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Epicurus – an ancient Greek philosopher and one of the first to advocate that the ultimate good is experiencing pleasure and avoiding pain.

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Utility – The thing that is ultimately valuable in itself. For Mill, this is happiness, which he then understands as pleasure and the absence of pain.

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Contract Theory – a modern political theory identifying consent as the sole justification for government. Contract theory is associated with Thomas Hobbes (1588-1679), John Locke (1632-1704), Jean Jacques Rousseau (1712-1778), and more recently, John Rawls (1921-2002)

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Prejudice – a foundational, strongly held, unreasoned (but not necessarily irrational) moral opinion or belief. We might believe, for example, that parents have special obligations towards their own children.

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A Priori – a philosophical term of art meaning (in Latin) “prior to experience,” which refers to knowledge that is innate or arrived at purely through reasoning, like the truths of mathematics.

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Rights – moral claims invoking immunity from (or entitlement to) some specific treatment (or good) from others. Commonly recognized rights include the right to free speech or the right to healthcare. 

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Reform – a change in the social order that originates from the existing character of society. An example would be market-based healthcare reform in a capitalist society.

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Conservatism – a modern political ideology that aims to preserve and promote the existing (or traditional)  institutions of society. These institutions typically include the rule of law, property, the family, and religion. 

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Contingent Being – A being that can fail to exist. Its existence is not guaranteed. This being might come to exist or it might not.

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Necessary Being – A being that can’t fail to exist. Its non-existence is impossible. This also means that such a being has always existed.

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Want to read more about why the infinite regress option doesn’t work in the Second Way? Check out Sean Floyd’s entry in the Internet Encyclopedia of Philosophy.

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Efficient Cause – An efficient cause is something that directly makes another thing exist or move. An example of this is when I kick a ball down a hill. I am the efficient cause of the ball rolling down the hill because I make it move down the hill.

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Infinite Regress: Begin with some fact. We begin to explain that fact by appealing to another fact, where these facts are related by either causality or dependence. To create the regress, you keep appealing to more and more facts about causality and dependence without end.

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Actuality – An ability or action something is currently exercising. Imagine that I am sitting comfortably at my desk, and then I stand up to take a break from reading. In this case, I am now actually standing. 

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Potentiality – What something has the capacity to do, but isn’t currently doing. Imagine I am sitting comfortably at my desk. Even though I’m not currently standing, I have the capacity to be standing. So, even while I’m not standing, I have the potential to stand. 

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Theists and Non-Theists – A theist is someone who believes that God exists, while a non-theist does not. Non-theists include atheists, who believe that God does not exist, and agnostics, who are uncertain about whether God exists.

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Glaucon – one of Plato’s brothers and one of Socrates’ main interlocutors in the Republic dialogue. In that dialogue, he challenges Socrates to provide a compelling justification for why one should be a just person beyond merely following conventions or avoiding punishment. This sets up Socrates’ defense of justice as intrinsically worthwhile. Throughout the Republic, Glaucon prods Socrates to fully explain his theories of the ideal society, philosopher-kings, and the Form of the Good.

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Aristotle – a Greek philosopher (384-322 BC) who studied under Plato and went on to be one of the most influential philosophers to ever live. Simply called “The Philosopher” by Thomas Aquinas and others in the medieval period, Aristotle’s views would eventually be synthesized with Christian theology, laying the intellectual foundation for later scholarly developments in Western Europe.

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Understanding – Socrates describes education as turning one’s “understanding” in the right direction. The word “understanding” here translates the ancient Greek term “to phronēsai,” which means “understanding,” “being conscious,” or “having insight.” People who are wicked focus their “understanding” on how best to accomplish their selfish and narrow desires. Those who are wise, in contrast, have learned to focus their “understanding” on what is truly good and beneficial.

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The Form of the Good – Socrates characterizes the ultimate goal of education as coming to know “the Form of the Good.” The Form of the Good is his technical term for the meaning of goodness: what it is to be good. Socrates is clear that this “knowledge of the Good” is not simply theoretical knowledge, but also knowledge in the sense of “knowing how”: knowing how to achieve what’s good, to do what’s good, to accomplish what’s good. Mere “book knowledge” or simply being smart is not enough.

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The Intelligible – Socrates uses “the intelligible” to name the aspects of the world that we can only grasp through thinking or insight. With my eyes I can see the tree outside my window, but what it means to be a tree is something I can only comprehend in thought. Likewise, I can see the people around me, but human nature, human dignity, and what it means to be human is something I can only grasp conceptually. “The intelligible” is the world insofar as it “makes sense” and can be comprehended.

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The Visible – By “the visible,” Socrates means those aspects of the world we can perceive with our five senses and our imagination—those aspects of the world we can see, hear, taste, smell, touch, and imagine. For example, with my eyes I can see the sky, trees, people around me, and so on as visible things. “The visible” is the world insofar as it can be perceived and imagined. 

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Education – Socrates says that the allegorical story he tells represents the effect of education on human nature. “Education” here is a translation of the ancient Greek word “paideia,” which means “education” in the widest sense of the term. “Paideia” doesn’t mean “education” in the sense of going to school or getting good grades. Instead, it refers to the process of becoming a wise, intelligent, good, and well-rounded human being.

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Allegory – An allegory is a symbolic narrative where characters, events, and/or settings represent abstract ideas or convey deeper meanings beyond the literal story. Socrates tells such a symbolic narrative in the passages below. The characters, events, and setting of his narrative symbolize the effect of what he calls “education.” 

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Self-knowledge – Knowledge of the contents of one’s own mind, such as one’s own beliefs and desires. Self-knowledge can be gained through introspection, that is, by reflecting on what one thinks and experiences. Some philosophers believe that self-knowledge has special properties that our knowledge of the external world lacks, such as being clearer, more reliable, or more valuable.

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Dualism – The view that the mind is entirely distinct from the body. This view is usually contrasted with different kinds of monism, which hold that the mind is ultimately just a part of the body (materialism) or that the body is ultimately just a part of the mind (idealism). Dualists hold that the mind and the body are fundamentally different aspects of reality, and both categories are needed to properly describe the universe, especially the human person. 

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The Self – What the ‘I’ in ‘I am, I exist’ refers to; the part of you that really makes you you. Many philosophers have provided rich accounts of what the self ultimately is, including the soul, the mind, one special feature of the mind (such as consciousness), a mixture of all these elements, or perhaps a mere illusion.  

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The ‘Cogito’ – Descartes’ famous claim ‘I think, therefore I am’ is often referred to as the cogito. The name comes from the Latin rendering of this phrase, which is ‘cogito, ergo sum.’ Descartes held that one can always believe this proposition with certainty. We cannot doubt our own existence, so the cogito survives his exercise of intense doubt. The cogito appears several times in Descartes’ writings, and he often phrased it slightly differently each time. It appears in the Second Meditation as ‘I am, I exist.’

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Certainty – When one believes something with certainty, one is maximally confident that it is true. A certainty is something that is beyond dispute or immune to doubt. Although this captures the basic idea, like many epistemological notions, clarifying precisely what the notion of certainty amounts to is an ongoing area of philosophical research. 

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Vice – A bad habit that we learn over time through instruction or instinct and that we develop through repetition. What makes the habit bad is that, once we have that habit, our tendency is to do the incorrect thing in certain types of situations. We may choose to do something entirely uncalled for in that situation, or we may act at the wrong time, in the wrong way, to the wrong degree, or with the wrong attitudes, or for the wrong reasons.

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Relative Mean – The “Goldilocks amount” of some type of action or emotion. When you act in this way, according to Aristotle, you act exactly as is required under the current circumstances. This means that you do what is called for by the situation at hand, rather than doing something too extreme or not doing something extreme enough. You do something in the moderate amount (the mean amount) relative to the specific situation you are in when you need to act.

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Excellence/Virtue – A good habit that we learn over time through instruction and repetition. What makes the habit good is that, once we have that habit, we have a strong tendency to do the right thing at the right time, in the right way, to the right degree, with the right attitudes, whenever we are confronted with a situation that we know calls us to exercise that habit.

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Doxastic Voluntarism – the view that we have at least some control over what we believe.

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Evidence – information that increases the probability that a claim is true.

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Sufficient – enough of something for a particular purpose. Whether something is sufficient is context-dependent.

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Solon – In the Histories of Herodotus, Solon visits Croesus, the king of Lydia. Even though Croesus shows Solon all of his wealth, Solon refuses to call him the happiest man who ever lived because he does not know how Croesus will die

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Priam – According to Greek mythology, Priam was the final king of Troy during the Trojan War. Despite his wealth and political power, he was killed by Achilles’ son Neopotolemus during the Sack of Troy

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Virtue – The consistent and reliable tendency to perform one’s function excellently. When a person has a certain virtue, like courage, they have spent time developing the habit, in this case reacting to danger well, using their human abilities. The virtues then make it possible for us to live a life of flourishing

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Sardanapalus – An Assyrian king described by the historian Diodorus as living a life of extreme decadence. Sardanapalus indulged himself with food, alcohol, and many concubines, even going so far to say that physical gratification is the purpose of life. Chrysippus said that, on his tomb is inscribed the following: “Though knowing full well that thou art but mortal, indulge thy desire, find joy in thy feasts. Dead, thou shalt have no delight […] I have only what I have eaten, what wantonness I have committed, what joys I received through passion; but my many rich possessions are now utterly dissolved.”

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Function – the characteristic activity of a given thing which makes it what it is. The function of a knife is cutting, while the function of a heart is to pump blood

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Eudaimonia – Frequently translated as ‘happiness’, eudaimonia means the attainment of active human flourishing, and is the end Aristotle identifies as humanity’s highest final good

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Final Good – A good that we pursue for its own sake. Common examples of final goods include happiness, knowledge, and friendship

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Instrumental Good – A good that we pursue for the sake of some other good. A common example is money, as money allows us to purchase other kinds of goods

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Anytus – an Athenian politician, war general, and  one of the primary accusers behind Socrates’ prosecution. Anytus feared that Socrates would undermine the young Athenian democracy he had helped create and defend

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Oracle of Delphi – the high priestess at the temple at Delphi, the oracle was one of the most sought after seers of the ancient world and was thought to relay messages from the god Apollo

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Chaerephon – an ancient Greek from the city Sphettus, Chaerephon is remembered as a loyal friend of Socrates, also making an appearance in two other Platonic dialogues, the Charmides and the Gorgias

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Meletus – A poet and citizen of Athens and one of Socrates’ accusers. Amongst other things, Meletus accused Socrates of corrupting the youth

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Apollo – the ancient sacred site Delphi was dedicated to the god Apollo, an ancient Greek god and the god that Socrates refers to throughout the Apology

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Virtue – a character trait, acquired through habitual practice, that enables one to act well. The virtues can also be thought of as excellences of human character, as they make it possible for us to live a life of flourishing. Examples of the virtues include courage, prudence, and justice

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The Evil Demon Argument – Argues that we cannot hold any of our beliefs with certainty because we could be radically deceived by an evil demon. A classic argument given by Descartes for doubting the reliability of almost all of our beliefs

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Philosophical Skepticism – The position that we do not know many things that we ordinarily take ourselves to know

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A Posteriori Knowledge – Knowledge that can only be acquired through having particular, concrete experiences. Such knowledge can be gained simply through our everyday experiences, or through more complex means like controlled scientific experiments

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A Priori Knowledge – Knowledge that can be gained without having any particular concrete experiences. Such knowledge is typically gained by rational insight or intuition

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Cartesian Method of Doubt – A process employed by René Descartes of rejecting all beliefs that he had at least some reason to doubt in order to see if he had any beliefs that he could know with certainty

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Revelation – Theological truths that have been made known by means of some religious text, testimony, authority, or experience, or the act or process in which such truths are made known.

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Rationalism – The view that the only reliable means of coming to know truths about God is reason. As a result, what we might otherwise believe by means of faith ought to be disregarded or even rejected in favor of what we must believe by means of reason.

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Fideism – The view that the only reliable means of coming to know truths about God is faith. As a result, what we might otherwise believe by means of reason ought to be disregarded or even rejected in favor of what we must believe by means of faith.

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Faith – The act of accepting a proposition as true for which there is less than demonstrable evidence, which rises above mere opinion but falls short of logical or scientific demonstration. Faith can also refer to a particular religious tradition or the body of beliefs that are central to that religious tradition.

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Virtue – a character trait, acquired through habitual practice, that enables one to act well. The virtues can also be thought of as excellences of human character, as they make it possible for us to live a life of flourishing. Examples of the virtues include courage, prudence, and justice

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Socratic Ignorance – an awareness of one’s own ignorance, and the reason that Socrates was deemed wise by the Oracle of Delphi. A person who lacks Socratic Ignorance may believe they know many things they actually don’t, leading them to overestimate how well they understand the world

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Apology – a formal defense of justification of an action or belief. A Christian apologist, for example, is someone who defends their faith and seeks to justify it through an appeal to reason.

Historical Connection

Solon’s Warning

In the Histories of Herodotus, Solon visits Croesus, the king of Lydia. Even though Croesus shows Solon all of his wealth, Solon refuses to call him the happiest man who ever lived because he does not know how Croesus will die

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Historical Connection

Priam

According to Greek mythology, Priam was the final king of Troy during the Trojan War. Despite his wealth and political power, he was killed by Achilles’ son Neopotolemus during the Sack of Troy

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