Summa Theologica Glossary
from Peter Kreeft’s Summa of the Summa
A
abstract
(opposite: concrete) not necessarily “spiritual” as vs. “material”, but some property, quality, or essence considered apart from the subject, thing, or substance that possesses it (e.g., justice, redness).
abstraction
the mental act of apprehending some form, quality, or essence without the rest of the object; considering a form without considering the whole, concrete material object or the image (*phantasm of it; e.g., abstracting the essential treeness, or the accidental bigness, of a tree from everything else in the concrete individual tree of what we see of it.
accident
(opposite: substance) that mode of being which can exist only in another being, as a modification or attribute of a substance (thing); e.g., the redness of a rose.
accidental
non-essential; non-substantial
agent intellect
the intellect in the act of abstracting form from matter; the intellect that informs and determines the potential, passive, or possible (receptive) intellect with this form.
analogical
the relationship between two things or terms which partly the same and partly different, neither univocal (wholly the same) nor equivocal (wholly different); the relationship of similarity but not identity between the meaning of a term when predicated of one subject (e.g., “milk is good”) and the meaning of that term when predicated of another subject (e.g., “God is good”).
appetite
in the widest sense, any inclination or tendency to some good or suitable object, or away from some bad or unsuitable object; more narrowly, in living things, the tendency to growth and health; still more narrowly, in animals, the senses’ desire for their natural object (see concupiscible appetite and irascible appetite); most narrowly, in man, the will’s desire for its proper good, happiness.
argument
a proof that a certain proposition (the conclusion) is true by showing (demonstrating) that it follows logically and necessarily from other propositions (premises) being true.
B
being
(1) that which is, whether actual or potential and whether in the mind (a “being of reason”) or in objective reality (a “being in nature”); (1A) ens: entity, thing, substance, that-which is; (1B) esse: the act of existing; (1C) essentia: essence, what a thing is; (2) the affirmative predicate “is” stating that the subject is, or is something (the predicate).
body
not just a human body, or an animal body, but any material thing that occupies space.
C
causality
influence of one being on another; responsibility of one being for some feature in another (the effect), such as its existence, its essence, its matter, its accidents, or its changes. See final cause, formal cause, efficient cause, material cause. In modern parlance “cause” usually means only “efficient cause”, i.e., that which produces existence or change in another.
change
actualization of a potency.
charity
the will to do good to another for his own sake.
common
(opposite: proper) present in two or more individuals or species.
concrete
(opposite: abstract) not necessarily material or sensible, but individual and actual.
contemplative
see speculative.
concupiscence
sense appetite seeking pleasure.
corporeal
pertaining to the body as distinct from the soul.
cosmos
the universe as ordered.
creation
the act of bringing a being into existence from non-existence; production of being from no pre-existing material.
deduction
argument from a more universal premise to a more particular conclusion, from a general principle to an instance or application of it.
demonstration
logically valid argument from premises that are true and evident, thus proving the conclusion with certainty.
determine
to cause some definite perfection; to specify, to make particular.
efficient cause
agent by which its acting produces existence or change in another.
emanation
flowing forth from a source.
end
good, goal, purpose, aim, obejctive.
epistemology
the science of knowing.
equivocal term
a term used with two wholly different meanings.
essence
in the broad sense, what a thing is, all its “intelligible notes” (characteristics) (as contrasted with its existence); in the narrow sense, as vs. accidents, the definition, or genus plus specific difference of a thing, that without which it cannot be deceived.
eternity
mode of existence without beginning, end, or succession; “the whole and perfect simultaneous possession of limitless life” (Boethius).
existence
the actuality of an essence, that act by which something is.
F
faculty
inherent power or ability.
final cause
end or purpose of a thing.
finite
limited.
form
the essential nature of a thing, that which signifies it to be this rather than that.
formal cause
form as determining matter.
G
genus
the aspect of thing’s essence which is common to it and other members of its species; a broader class to which a thing essentially belongs (e.g., “animal” for man, “plane figure” for triangle).
grace
that which comes from God’s free will, as distinct from natural necessity.
H
habit
disposition toward certain operations; inclination to an end. A “habit” is not a “rut”, but is freely made, in man, by repeated acts.
happiness
satisfaction of desire in really possessing its true and proper good. (Note that there is both a subjective and an objective element in happiness; thus neither a stone nor an evil man can be happy.)
I
idea
concept.
image
representation or likeness.
imagination
internal sense which produces images of sensible, material things even when they are absent.
incorporeal
immaterial, without body.
incorruptible
incapable of decay or destruction.
individual
that which cannot be divided without losing its identity.
induction
reasoning from individual cases to general principles, from more particular premises to more universal conclusions.
infallible
incapable of error, thus certain.
inference
reasoning from some truths (premises) to others (conclusions).
infinite
unlimited.
infused
received from without.
innate
inborn, given by nature.
irascible appetite
sense desire to fight a danger.
J
judgement
act of the mind comparing two concepts (subject and predicate) in an affirmative or negative proposition.
L
life
the power of a substance to move itself
locomotion
motion in space
M
matter
the principle in a thing’s being by which it is able to be determined by form; potency as vs. actuality. In modern parlance, the word refers to actual, visible, formed things (e.g., chemicals, molecules); but in Thomistic and Aristotelian parlance “matter” is not of itself observable or even of itself actual. It is not a thing but a metaphysical principle or aspect of things, which together with form explains change, as the actualization (in-form-ing) of potency (matter).
material cause
that (potency) from which a thing is produced—e.g., the clay of a pot.
mean
something in the middle between two extremes.
metaphysics
that division of philosophy which studies being as such, and the universal truths, laws, or principles of all beings; “the science of being qua being”.
motion
broadly, any change; more narrowly, change of place, or locomotion.
N
natural
(1) as vs. artificial: found in nature, what a being has from birth, what happens by itself without outside interference (art or violence); (2) as vs. supernatural: what is or happens without direct, divine intervention; (3) as vs. rational: without intelligence (e.g., “natural bodies”); (4) as vs. arbitrary or conventional: what flows from a thing’s essence; necessary.
necessary
what cannot be otherwise.
nominal
(as vs. real) pertaining to a name only. “Nominalism” is the theory that universal terms like “justice” or “man” are only names, not real essences; it is perhaps the most pervasive and destructive error in modern philosophy.
P
participation
sharing in, possessing some perfection of.
passion
in general, receptivity, being acted on by another, in particular, intense movement of the sensitive appetite.
passive
in potency to be determined by another agent.
patient
any being that is changed by an agent.
perfection
most generally, any definite actuality in a being; more particularly, any definite good suitable to a being; most particularly, complete good attained by a being.
phantasm
sense image.
philosophy
literally, the love of wisdom; the science that seeks to understand all things by knowing their causes by natural reason.
possible
that which can be.
potency
or potentiality the principle of change; capacity or ability to be actualized in some way.
predicate
(noun): term that says something about the subject; (verb): to state something about a subject.
principle
source; that from which something proceeds.
proper
distinctive, special, specific (as vs. common).
property
“proper accident”, an attribute that is not the very essence of the subject but results from its essence (e.g., speech in man or greenness in chlorophyll).
proposition
declarative sentence, affirmative or negative.
providence
intelligent plan by which things are ordered to an end.
prudence
practical wisdom, knowing how to choose good means to good ends, what to do and how to do it. It has none of the prudish, prune-like, over-careful connotations of the word in modern parlance.
Q
quiddity
whatness, essence.
R
reason
(1) most generally, that which distinguishes man from brute animals: intelligence; (2) more specifically, the power of reasoning (all three “acts of the mind”: conceiving, judging, and arguing); (3) most specifically, the power to argue or prove (the “third act of the mind”).
reduction
the mental act of bringing something complex back to a more fundamental or elementary form or principle, or seeing it within a general principle or class.
S
science
intellectual knowledge by means or causes or general principles. In one way, “scientific” meant something narrower and tougher in pre-modern times: certain knowledge of real causes. In another way, it meant something broader and looser than the modern scientific method, for it did not always require experimentation or mathematical measurement.
sensation
act of one of the five senses.
simple
not composed of parts.
sin
any human act (deed, word, or deliberate desire) in disobedience to divine law.
soul
generally, the first intrinsic (inner, natural) principle of life in a living body; specifically, the human soul is the first principle of human, rational life, i.e., of knowing and willing.
species
(1) in logic, the class to which a thing essentially belongs, expressing both the genus and the specific difference (e.g., “man is a rational animal”); (2) in epistemology, a likeness or representation of an object, the form of an object known.
specify
to determine to a definite form or class.
speculative
(opposite of practical) contemplative; knowledge for the sake of knowledge, seeking the truth for its own sake rather than for action (doing something with it) or production (making something by it). “Speculative” does not necessarily mean “uncertain” or “hypothetical”.
subject
(1) in logic, the term in a proposition about which something is said in the predicate; (2) in metaphysics, a substance in relation to attributes; (3) in epistemology, a knower as distinct from an object known.
substance
a being that exists in itself rather than in another (as vs. accident).
supernatural
beyond the power of nature, caused by God alone without secondary (natural) causes.
syllogism
(1) logical argument; (2) especially a deductive argument; (3) especially a certain deductive argument, with three terms, two premises, and one conclusion.
T
term
(1) in metaphysics, the first or last point of a series; (2) in logic, the subject or predicate of a proposition, expressing a concept.
transcendent
greater than, superior to.
transcendental
universally common to all things. The five transcendental properties of all being are: something, one, true, good, beautiful.
truth
conformity of the mind to real things.
U
universal
general, common to many.
univocal
having the same meaning when predicated of different things.
virtual
having an active, positive potency to some perfection; more than merely passively potential, but less than actual.
virtue
good habit.
W
will
rational appetite; power of the soul to desire or choose a good known by the intellect.