The concept of first cause, by which, in the absolute sense, God is understood, is derived from the metaphysical demonstration of the necessity of an ultimate efficient per se (direct) cause of the existence of multiple and diverse finite realities (St. Thomas, Summa theologiae, 1a, 2.3). The first cause is the ultimate uncaused cause, the one cause of all other reality. In the relative sense, the first cause may be the cause that is first in any order of created causes.
Finite reality, in which essence and existence are distinct, requires an efficient proper cause of its being, for its nature is not sufficient reason for its finite existence. A proper effect demands the actual operation of the cause of which it is the effect and ceases with the cessation of that cause (St. Thomas, Summa theologiae 1a, 104.1). Whatever demands a cause of its becoming (in fieri ), demands also a cause of its existence (in esse ), since the first of all effects is being, which is presupposed to all other effects, and does not presuppose any other effect (St. Thomas, Summa contra gentiles, 2.21). Continued existence, therefore, is a present effect that must be due to the operation of the present cause of that existence.
The argument proceeds from the premise, an obvious fact of sensory and intellectual experience, that realities, both substance and accidents, come into existence through the action of a series of essentially subordinated efficient causes. But it is a contradiction in terms that such a series should proceed to infinity. The existence of a first cause, itself uncaused and self-subsistent, must be admitted necessarily.
The same conclusion follows an argument proceeding from the consideration of contingent realities (that may either exist or not exist). It is evident that such realities are not the reason for their own existence, otherwise they would be self-existent. Their existence, therefore, must be the effect of the proper efficient first cause of existence. The existence of all being, therefore, is the direct proper effect of the per se causality of the first uncaused cause.
All causes, other than the first cause, whether they be properly principal or instrumental, are secondary causes whose very existence as causes, as well as whose operations as causes, is an effect of their proper direct cause, God Himself.
The concept of first cause, therefore, signifies not only the primary causality of all causal activity in the created universe, but the primary causality of the very being of all causes. Moreover, the conservation of all created reality in existence is the proper effect of the first cause, whether the reality be of the material or spiritual order, or the composite of the two. Whatever is, or can be, is an effect of the first, efficient, causality of the first cause.
See Also: exemplarism; exemplarity of god; god in philosophy; god, proofs for the existence of; good, the supreme.
Bibliography: Dictionnaire de théologie catholique, ed. a. vacant et al., 15 v. (Paris 1903–50; Tables générales 1951–), Tables générales 1:557–560. j. de vries et al., Lexikon für Theologie und Kirche, ed. j. hofer and k. rahner, 10 v. (2d, new ed. Freiburg 1957–65) 6:96–100. i. m. dalmau, Sacrae theologiae summa, ed. Fathers of the Society of Jesus, Professors of the Theological Faculties in Spain, 4 v. (Madrid), v. 1 (5th ed. 1962), v. 2 (3d ed.1958), v. 3 (4th ed. 1961), v. 4 (4th ed. 1962); Biblioteca de autores cristianos (Madrid 1945– ) 61, 90, 62, 73, 2.1:1–36.
[m. r. e. masterman]