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

scholastic philosophy Scholasticism was a medieval European philosophical movement or methodology that was the predominant education in Europe from about 1100 to 1700. It is known for employing logically precise analyses and reconciling classical philosophy and C ...

. The

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

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

essence Essence () has various meanings and uses for different thinkers and in different contexts. It is used in philosophy and theology as a designation for the property (philosophy), property or set of properties or attributes that make an entity the ...

, power supposes

existence Existence is the state of having being or reality in contrast to nonexistence and nonbeing. Existence is often contrasted with essence: the essence of an entity is its essential features or qualities, which can be understood even if one does ...

, and faction 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''), 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) is a pure potentiality, and the substantial form is its first determination, its first actuality. The complete substance 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 or chemical 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. The terms "intensive and extensive ...

of a substance is a first actuality when compared to the

shape A shape is a graphics, graphical representation of an object's form or its external boundary, outline, or external Surface (mathematics), surface. It is distinct from other object properties, such as color, Surface texture, texture, or material ...

. Power is a first actuality when compared to action. 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 r ...

and

kinetic energy In physics, the kinetic energy of an object is the form of energy that it possesses due to its motion. In classical mechanics, the kinetic energy of a non-rotating object of mass ''m'' traveling at a speed ''v'' is \fracmv^2.Resnick, Rober ...

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

{{Catholic philosophy footer Scholasticism Concepts in metaphysics

See also

References