Thomas Aquinas Glossary
to Accompany Treatise on Happiness
and Treatise on Human Acts

included in Treatise on Happiness
translated by John A. Oesterle
(University of Notre Dame Press, 1983)

Instructor: Dr. Jan Garrett

Last revised date: October 11, 2005

Go to A D G I M R V

This is a somewhat rough guide to the vocabulary of Thomas Aquinas in his Treatises on Happiness and Human Acts. It is meant as an aid to students struggling with the texts for the first or second time. Scholars should of course confirm or correct such definitions against the words of Thomas' texts themselves. If anyone familiar with the relevant texts discovers errors, please point them out to me.-Jan Garrett

accident - in logic, a predicate that is attributed to a subject in fact but not by necessity. "Accident" in this sense should not be confused with a per se or proper accident.

act -- see first act, second act, potency; action, two types of

action - (1) one type involves external object (e.g., opening an envelope); (2) the other is complete in itself (e.g., thinking a mathematical truth). In sense (2), action corresponds to activity.

activity (operatio) - another name for 2nd act, especially when it concerns human faculties. Performing a virtuous activity (use of practical intellect) and contemplating known truths (use of speculative intellect) are examples of activity. See potency.

antecedent involvement - if X could not come into existence without Y existing beforehand, then X antecedently involves Y. Thus, since general knowledge is requires prior sense-experience, knowledge antecedently involves the senses; see essential involvement and consequent involvement

appetite - an inclination or bent to a good, used 1. of any potency with respect to its act; 2. of any being [with respect] to its fulfilment though not mediated by knowledge (natural appetite); 3. of conscious desire [sense appetite]; 4. of rational appetite or will. (This definition is based on Summa Theologiae [Blackfriars, 1969], vol. 16, p. 156.)

choice - an act of the will in relation to the means (q. 13); compared with intention, which is properly related to the end, choice is of the means (to an intended end). Choice is a result of deliberation.

composition - synthesis, the combining of simpler things to produce something more complex; actions aimed at producing a complex result proceed by composition, but what had to be done was figured out by deliberation, using resolution (analysis).

concupiscence - actualized appetite for what is physically pleasant

concupiscible power - one of two major types of sense appetite. The other is irascible power.

consequent involvement - if Y reliably results from X but is distinguishable from it, then X consequently involves Y

contingent truth - a proposition that happens to be true but is not a necessary truth

created being - a being that exists as the result of another being; aka contingent being

deliberation - inquiry that proceeds from a conception of a desirable end to the choice of act that will lead to that end; is not used when strict science or art dictates what should be done but only where there is some indeterminacy; proceeds by resolution rather than composition. See inquiry, resolution.

delight - pleasure or a specific kind of pleasure; see happiness

demerit - that which is rendered in accordance with justice or recompense as a result of evil acts (q.21, a. 3); see merit, recompense.

demonstration - roughly, valid deductive reasoning from true primary premises; the premises of demonstration are themselves necessary truths and "better known" than the conclusion (knowledge of which depends on them).

Demonstration, essential to science, is contrasted with deliberation and with dialectical arguments whose premises are either not known to be true or are not known to be necessarily true.

See necessary truth; science; deliberation.

divine essence - the essential nature of God, the intellectual vision of which, according to Thomas, constitutes perfect happiness. It is one thing to know that God exists (e.g., as creator of the material world), another to understand by intellectual vision what He is.

end - that to which a thing is ordered by the will of a rational being; a real or apparent good. See means, order (verb); proximate and remote; irrational creature; happiness

enjoyment - the delight one experiences in acquiring the ultimate end

essence (aka "very being") of a thing; relate to and contrast with per se accident. The essence of a thing is stated in its (real) definition, which explains the per se accidents of a thing. For instance, the essence of a lunar eclipse is the earth's blocking the light of the Sun; if the only thing that could cause a circular shadow to fall on the moon were the earth's blocking the light of the Sun, then this event (circular shadow falling on the moon) would be a per se accident of the lunar eclipse.

essential involvement = if X essentially involves Y, then the definition of X includes Y

eternal law - God's mind insofar as it may be considered the supreme rule that governs human actions. See also reason.

existence per se - related to and contrasted with existence by reason of (or because of) something else. Per se beings exist because of their nature - God alone is a per se being. Beings that exist by reason of other things are caused to exist by other things. In Thomas' view, all created beings exist by reason of other things.

exterior principle - an external cause

first act; see potency and second act, to which it is related and with which it is contrasted.

form - always explicitly or implicitly related to and contrasted with matter. Matter tends to correlate with potency and form with first act. (See those terms as well.)

good - see end.

goods - (1) external, e.g., wealth, favorable reputation; (2) of the body, e.g., health, physical beauty; (3) of the soul, e.g., moral and intellectual virtues, activities expressing such virtues

habit - a quality by which a being or a power is well or badly disposed. There are habits of the body, e.g., strength and weakness, and habits of the soul. Grace is a habit in the soul as a whole; the intellectual, moral, and theological virtues are habits in the parts of the soul.

happiness - the ultimate end for rational beings, including humans; requires possession of the virtues. See end, virtue.

happiness, common notion of -- happiness understood as a perfect or complete good

happiness, particular notion of - happiness understood as the vision of the divine being aka the supreme good (God is the particular object of happiness, according to Thomas)

human virtues - virtues that can be produced in us by teaching or habituation; they include the intellectual virtues and the moral virtues. Human virtues are distinguished from theological virtues.

inquiry - a mental process in which one seeks an answer to a question whose answer is not yet known (by the questioner).

intellect; see speculative and practical. "Intellect" sometimes means just speculative intellect, the power of understanding what something is and knowing truth (q. 9, a. 1). The intellect also has an important moral function; it has an apprehension or perception of particular goods that it presents to the will; this is the way the intellect "moves" the will. Since this perception is not necessarily correct, the will may pursue particular goods that it ought not pursue. Another function in the intellect in relation to action is deliberation.

intellectual virtue - excellence of the intellect or rational part of the soul; intellectual virtues include science, art, and prudence

intellectual vision - the intellectual activity by which the soul of the good person, in the afterlife, knows the divine essence; this "vision" is beatific, that is, it constitutes perfect happiness in the soul

intention - a tending to some end; properly an act of the will; the object of an intention is the end. (q.12, a. 1, R)

involvement = see essential, antecedent, and consequent

irascible power- the power or faculty of the soul with which we get angry (roughly equivalent to what Plato calls the "spirited part" of the soul). The irascible and concupiscible powers make up sense appetite. In the good person, the irascible and concupiscible powers are well disciplined and under the control of reason.

irrational creature, ends of - such creatures are ordered to their ends by the Creator. In Aquinas' view, such creatures are not ordered to happiness.

matter - always explicitly or implicitly related to and contrasted with form. Matter tends to correlate with potency and form with first act. (See those terms as well.) Aristotelians introduce the concepts of matter with simple examples (e.g., bronze names the matter of a bronze sphere and sphere names the form), but they can also use these concepts to explicate more abstract distinctions, e.g., in a living being, the body (considered in abstraction from life) is matter, and soul (as a principle of life) is form.

means - that which is chosen because it is thought to contribute to the production of an end (a real or apparent good); probably called a means or middle because it seems to stand between the wish for the end (which, through deliberation, leads to the choice of means) and the production of the end. See order (verb).

merit - that which is attributed to a person in accordance with justice or recompense in response to good acts (q. 21, a. 3); see demerit, recompense

moral virtue - a habit or trained disposition, shaping the way one feels in various situations and the way one deliberates and chooses. A virtuous person feels and chooses in ways that agree with (right) reason, the right reason of the prudent person; see prudence. The morally virtuous person has appropriate ends and is able to deliberate well. Moral virtues include justice, courage, temperance, generosity, and the like. The opposite of moral virtue is moral vice. Besides moral virtues, Thomas thinks there are theological virtues (faith, hope, and charity).

nature - a term with many meanings: (1) the intrinsic principle of things that move; (2) the matter of a material thing; (3) the form of a material thing; (4) the substance or essence (aka being) of a thing. (q. 10, a. 1, R)

necessary truth - proposition or statement that cannot be false; contrasted with contingent truths (propositions that happen to be true but might have been false) and self-contradictory statements (propositions that are necessarily false).

object (of will, vision, etc.) - the "target" of a mental act. For instance, the object of will is the end aimed at, the object of vision is a visible external thing

order (verb) - for a rational agent to order Y to X is for that agent to regard Y as a means toward X.

participate (verb): usually followed by "in" (occasionally "of"). One thing participates in another when the former expresses the characteristic quality of the latter, but less completely or intensely. The term is usually used when the writer sees the two beings as on lower and higher metaphysical levels, respectively. They share a common quality but are not necessarily members of the same community, social group, or social activity. See "participation."

participation - relationship between something at a lower metaphysical level and a similar thing at a higher metaphysical level. The phrase is Platonic: Platonists say, for instance, that a beautiful person participates in the ideal Form of Beauty. Thomas says in q. 3 a. 2 that in the present life "there is a participation in [perfect] happiness," by which he means that in the imperfect happiness available in the present life, there is a "shadow" of the perfect happiness a person may have (later) in the presence of God.

passions - feelings based on the sense appetite, i.e., on the irascible or concupiscible powers of the soul. They include, for instance, fear, anger, desire for money, and sexual desire, not as capacities or powers but as actual instances of the similarly named capacities.

per se accident; also called proper accident

per se existence; see existence per se

potency. This concept must be understood in relation to first act and second act.

Aristotle (from whom Aquinas gets it) introduces it by means of examples. The ability to learn (say, one's multiplication tables) illustrates potency; knowledge (of such tables) illustrates first act; actually thinking the mathematical truths involved illustrate second act. The eye as a physical organ illustrates potency; the capacity for vision of a healthy eye illustrates first act; actually seeing something with a healthy eye illustrates second act. The ability to become honest (shared by most young persons) illustrates potency; being honest (having developed the virtue of honesty) illustrates first act; voluntarily doing the honest thing from honesty illustrates second act.

practical intellect - the rational faculty that governs desire; roughly the will, rational desire (or rational appetite)

principle - first thing, starting point, cause, premise. Ends are principles or causes in that we begin our deliberation about action from some notion of an end. In a geometrical proof, the postulates and definitions that supply starting points are considered principles.

proper accident - Aristotle and Aquinas distinguish the proper accident of a thing from the essence of that thing. The proper accident of something accompanies it but does not explain it, but the essence of thing may explain or help to explain the presence of the proper accident. Only the definition of the essence explains it. According to Thomas, delight is the proper accident of happiness but not its essence. See also accident.

prudence - the primary intellectual virtue related to moral and political conduct; it enables the person who has it to deliberate and choose well. It cannot be present unless the person has the moral virtues too. Aquinas' notion of prudence is a version of Aristotle's notion of phronesis (often translated practical wisdom).

reason - the rational faculty, usually contrasted with the passions, or with the sensible and irascible appetites; sometimes equated with intellect, sometimes not; when contrasted with intellect, reason has to do with reasoning, as in inquiry or deliberation or proof while intellect relates to the direct mental grasp of basic truths.

(Right) reason may be considered a standard or a rule of human action; it is (q. 21, a. 1) the proximate rule, the rule closest at hand, in contrast to the supreme rule, the eternal law in the mind of God. Right ordering of action to an end is determined by a rule. (ibid.)

recompense - a sort of "payback," rendered to someone accordance with justice for his benefit or injury to another (q. 21, a. 3)

resolution - analysis, the breaking up of a complex whole into parts; the opposite of composition or synthesis. Resolution is part of the process of deliberation.

right (moral right) - the quality of human acts that tend to the end according to the order of reason and the eternal law; Thomas adds that an act is right by reason of being good. (q. 21, a. 1) See reason as a rule.

(to be) said in two [three, ůmany] ways - has two [three, ůmany] distinct meanings. This phrase is used when discussing meanings of key words like "nature."

science - an intellectual virtue that enables its possessor to demonstrate (deduce) truths based on apprehension of basic truths. The propositions known by science are arranged in a deductive system, in which general primary premises known by intellect lead necessarily to general conclusions. Scientia is a translation of Aristotle's episteme. (Euclidean geometry is the model for science.)

second act; see potency

sense appetite - a general name for the irascible and concupiscible powers of the soul, the powers on which the passions are based. Sense appetite is contrasted with rational appetite or will. Sense appetite is said to be passive with respect to the will, an active power.

sin (=moral wrong) - the quality of human acts when they deviate from what makes a voluntary act right (see right); Thomas says that a human act is sinful by reason of being evil. (q. 21, a. 1)

speculative intellect - the faculty of knowing for the sake of knowing

speculative science - sometimes just called "science"; the type of knowing characteristic of the speculative intellect; see speculative intellect and science

subject - as in the phrase "in a subject." Things that are present "in a subject" could not exist apart from a subject, but they are related to it without necessity. Baldness is in Socrates as in a subject (Socrates might not be bald); courage is in a human being's irascible appetite as in a subject (the person might not be courageous, or, more accurately, courage might be absent from her irascible appetite).

theological virtues - virtues in the powers of the human soul that cannot be produced in us without divine grace; they include faith (located in the intellect); hope (located in the will); and charity (located in the will). Contasted with the human virtues.

virtue - a habit or perfection of the soul; see intellectual virtue, moral virtue, prudence

will - the first principle of action; internal to a rational agent; closely associated with intention, deliberation, and choice; called "rational desire" (q. 1., a. 2, R), "rational appetite" (q. 6, a. 3, r. 1), it is not necessarily correct. The "proper object" of will is the end, but one can will (aim at or choose) a means with reference to an end. The will is active in relation to sense appetite. It is perfected by the moral virtue of justice (q. 59 a. 4; q. 61 a. 2) Will is discussed at length in the Treatise on Human Acts. See also intention, deliberation, choice, practical intellect.