''Actus primus'', or first actuality, is a technical expression used in

scholastic philosophy Scholasticism was a medieval school of philosophy that employed a critical organic method of philosophical analysis predicated upon the Aristotelian 10 Categories. Christian scholasticism emerged within the monastic schools that translate ...

. The

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

word ''actus'' means determination, complement. In every being there are many actualities, which are subordinated. Thus existence supposes

essence Essence ( la, essentia) is a polysemic term, used in philosophy and theology as a designation for the property or set of properties that make an entity or substance what it fundamentally is, and which it has by necessity, and without which it ...

; power supposes

existence Existence is the ability of an entity to interact with reality. In philosophy, it refers to the ontology, ontological Property (philosophy), property of being. Etymology The term ''existence'' comes from Old French ''existence'', from Medieval ...

; action supposes faculty. The first actuality (''actus primus'') begins a series; it supposes no other actuality preceding it in the same series, but calls for a further complement, namely, the second actuality (''actus secundus''). But as the same reality may be called "actuality" when viewed in the light of what precedes, and "potentiality" when viewed in the light of what follows (see ''

actus et potentia In philosophy, potentiality and actuality are a pair of closely connected principles which Aristotle used to analyze motion, causality, ethics, and physiology in his ''Physics'', ''Metaphysics'', ''Nicomachean Ethics'', and ''De Anima''. The c ...

''), the meaning of the term "first actuality" may vary according to the view one takes, and the point where the series is made to begin. Primary matter (see

matter and form Hylomorphism (also hylemorphism) is a philosophy, philosophical theory developed by Aristotle, which conceives every physical entity or being (''ousia'') as a compound of matter (potency) and Substantial form, immaterial form (act), with the gener ...

) is a pure potentiality, and the substantial form is its first determination, its first actuality. The complete

substance Substance may refer to: * Matter, anything that has mass and takes up space Chemistry * Chemical substance, a material with a definite chemical composition * Drug substance ** Substance abuse, drug-related healthcare and social policy diagnosis ...

constituted by these two principles receives further determinations, which are, in that respect, second actualities. Yet these may also be conceived as first actualities. Thus the

extensive quantity Physical properties of materials and systems can often be categorized as being either intensive or extensive, according to how the property changes when the size (or extent) of the system changes. According to IUPAC, an intensive quantity is one ...

of a substance is a first actuality when compared to the

shape A shape or figure is a graphics, graphical representation of an object or its external boundary, outline, or external Surface (mathematics), surface, as opposed to other properties such as color, Surface texture, texture, or material type. A pl ...

. Power is a first actuality when compared to action. And this is the most frequent application of the terms ''actus primus'' and ''actus secundus''. The former is the faculty; the latter, the exercise or function. To see ''in actu primo'' simply means to have the sense of vision; to see ''in actu secundo'' is to actually perform acts of vision. The modern distinction of

potential Potential generally refers to a currently unrealized ability. The term is used in a wide variety of fields, from physics to the social sciences to indicate things that are in a state where they are able to change in ways ranging from the simple re ...

and

kinetic energy In physics, the kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its accele ...

might serve as another illustration: the loaded gun, or the engine with steam buildup, represent first actualities; the bullet speeding to the mark, the engine flying over the rails, represent second actualities.

References

Scholasticism {{philo-stub

See also

References