¹ St. Thomas Aquinas, Summa Theologiae, (Textum Leoninum Romae 1888 editum), ST I q.45, a. 6, co.: “Ut enim supra ostensum est, cum de Dei scientia et voluntate ageretur, Deus est causa rerum per suum intellectum et voluntatem, sicut artifex rerum artificiatarum. Artifex autem per verbum in intellectu conceptum, et per amorem suae voluntatis ad aliquid relatum, operatur.” English translations, unless noted, are taken from Aquinas, Thomas St., Summa Theologica: Complete English Edition in Five Volumes, trans. the Fathers of the English Dominican Province (Notre Dame, IN: Ave Maria Press, 1981)Google Scholar.

² In treating the image none of the following scholars mention instrumental causality: Kondoleon, Theodore, Exemplary Causality in the Philosophy of St. Thomas Aquinas, Ph.D. diss. (Washington, D.C.: The Catholic University of America, 1967)Google Scholar; Boland, Vivian, Ideas in God according to Saint Thomas Aquinas (New York: E.J. Brill, 1996)CrossRefGoogle Scholar; Doolan, Gregory, Aquinas on the Divine Ideas as Exemplar Causes (Washington, DC: The Catholic University of America Press, 2008)Google Scholar; Fr.Perret, Marie-Charles, “La notion d'exemplarité.” Revue Thomiste 41 (1936), pp. 446–69Google Scholar; Meehan, Francis, “Efficient Causality in Aristotle and St. Thomas.” PhD diss., (Washington, D.C.: Catholic University of America, 1940), p. 180–81Google Scholar.

³ St. Thomas Aquinas, Sententia libri Metaphysicae (Textum Taurini 1950 editum), Com. Meta. V l.3, n. 783. These are only accidental differences and thus do not divide the causes essentially.

⁴ Reith, Herman, The Metaphysics of St. Thomas Aquinas (Milwaukee: The Bruce Publishing Company, 1962), p. 156–58Google Scholar.

⁵ Meehan, p. 181.

⁶ Perrett, 461: “Séparer la cause efficiente de la cause exemplaire, c'est donc pratiquer un morcelage aussi pénible que celui d'un artiste produisant une oeuvre d'art sans idéal, d'un idéal aboutissant à une œuvre d'art sans artiste.”

⁷ Aquinas's ex officio treatments (according to Meehan) are: “IV sent. 1.1.4; de verit. 27.4; de pot 5.1.6 and 5.6.4; SCG III 66 ; ST I-II q. 62, a. 1.”

⁸ E.g. Aquinas conceives of the relation of all finite agents to God in terms of instrumentality. Cf. SCG III c. 70.

⁹ St. Thomas Aquinas, Questiones Disputatae de Potentia (Textum Taurini 1953 editum), De Pot. q.3, a. 7: “Sic ergo Deus est cause omnis actionis, prout quodlibet agens est instrumentum divinae virtutis operantis.” Cf. also, SCG II, 21: “Omnis… alia substantia praeter Dum est causata inquantum habet esse causatum ab alio. Impossibile est igitur quot sit causa essendi nisi sicut instrumentalis et agens in virtute alterius.”

¹⁰ It seems that Aquinas here means motion in an improper sense (change) and not locomotion (especially if one is to make sense of his using instrumentality to express all finite causality in relation to God. Cf. St. Thomas Aquinas, Summa Contra Gentiles (Textum Leoninum, 1961 editum), SCG III c. 70). Cf. St.Aquinas, Thomas, Commentary on the Physics of Aristotle (Notre Dame: Dumb Ox Press, 1999), III, l. 2, nn. 285–86Google Scholar. Cf. also Wippel, John, The Metaphysical Thought of Thomas Aquinas (Washington, D.C.: The Catholic University of America Press, 2000), p. 445–46Google Scholar. Motion is properly said only of changes in quality (alteration), place (locomotion), and quantity (increase/decrease). Motion can improperly be said of changes in substance (generation/corruption) and even more broadly of any transition from potency to act whatsoever (the action of something in potency insofar as it is in potency, i.e. change).

¹¹ De Pot. q. 5, a. 5, co.

¹² On the other hand, there is certainly development beyond this simple identification. The difference may be seen when comparing St. Thomas Aquinas, De Veritate (Textum Leoninum 1972 editum), q. 27, a. 4, ad 3 (DV), SCG II c. 89 & SCG III c. 70. Put simply it is the difficulty of reconciling SCG II c. 89: “This accounts for our observation of the fact that an effect produced by a principal agent through an instrument is more properly attributed to the principal agent than to the instrument. In some instances, however, the action of the principal agent attains to something in the effect produced, to which the action of the instrument does not attain” with SCG III c. 70: “rather, it is wholly done by both, according to a different way, just as the same effect is wholly attributed to the instrument and also wholly to the principal agent.” For some aspects of this development see O.P.Blankenhorn, Bernhard, “The Instrumental Causality of the Sacraments: Thomas Aquinas and Louis-Marie Chauvet,” in Nova et Vetera, English Edition, Vol. 4, No. 2 (2006), pp. 255–94Google Scholar.

¹³ Aquinas only mentions this division in his early DV. It does not seem he would have to abandon it in his later development on the causality of an instrument. Hence, one may consider it as at least compatible with his mature thought wherein he utilizes the term instrument for both free and determined agents.

¹⁴ DV q. 24, a. 1, ad 5: “Ad quintum dicendum, quod instrumentum dupliciter dicitur. Uno modo proprie; quando scilicet aliquid ita ab altero movetur quod non confertur ei a movente aliquod principium talis motus; sicut serra movetur a carpentario: et tale instrumentum est expers libertatis. Alio modo dicitur instrumentum magis communiter quidquid est movens ab alio motum, sive sit in ipso principium sui motus, sive non. Et sic ab instrumento non oportet quod omnino excludatur ratio libertatis; quia aliquid potest esse ab alio motum, quod tamen seipsum movet: et ita est de mente humana.” Cf. Also ST I q. 36, a. 3, ad 2 & SCG II c. 21: “But it is only in order to cause something by way of motion that an instrument is ever employed; for to be a moved mover is the very essence of an instrument.” It would seem that Burrell's distinction between instrument and secondary cause breaks down with this citation and SCG III c. 70. What Burrell wants to identify as a secondary cause is really an instrument in the broad sense. Likewise, what Burrell identifies as strictly secondary causality is identified by Aquinas as instrumentality in SCG III c. 70. Cf. Burrell, David, Freedom and Creation in Three Traditions (Notre Dame: University of Notre Dame Press, 1993), 97Google Scholar. Nevertheless, this does not mean there is no difference between the third and fourth ways God works in nature. cf. Meehan, 298–99.

¹⁵ DV q. 27, a. 4, co: “Haec enim est ratio instrumenti, in quantum est instrumentum, ut moveat motum; unde, sicut se habet forma completa ad per se agentem, ita se habet motus quo movetur a principali agente, ad instrumentum, sicut serra operatur ad scamnum. Quamvis enim serra habeat aliquam actionem quae sibi competit secundum propriam formam, ut dividere, tamen aliquem effectum habet qui sibi non competit nisi in quantum est mota ab artifice, scilicet facere rectam incisionem, et convenientem formae artis. Et sic instrumentum habet duas operationes: unam quae competit ei secundum formam propriam; aliam quae competit ei secundum quod est motum a per se agente, quae transcendit virtutem propriae formae.”

¹⁶ ST III q. 62, a. 1, ad 2: “Ad secundum dicendum quod instrumentum habet duas actiones, unam instrumentalem, secundum quam operatur non in virtute propria, sed in virtute principalis agentis; aliam autem habet actionem propriam, quae competit sibi secundum propriam formam; sicut securi competit scindere ratione suae acuitatis, facere autem lectum inquantum est instrumentum artis. Non autem perficit actionem instrumentalem nisi exercendo actionem propriam; scindendo enim facit lectum. Et similiter sacramenta corporalia per propriam operationem quam exercent circa corpus, quod tangunt, efficiunt operationem instrumentalem ex virtute divina circa animam, sicut aqua Baptismi, abluendo corpus secundum propriam virtutem, abluit animam inquantum est instrumentum virtutis divinae; nam ex anima et corpore unum fit. Et hoc est quod Augustinus dicit, quod corpus tangit et cor abluit.”

¹⁷ De Pot., q.3 a. 4: “in the sense that the second cause could have a twofold action, one proceeding from its own nature, and the other from the power of a preexisting cause.” Nevertheless, in order to understand an instrument's nature one must know the end to which it is ordained. Cf. DV q. 2, a. 5, s.c. 3.

¹⁸ Clark, Mary T., An Aquinas Reader (New York: Fordham University Press, 2000), p. 78Google Scholar. Cf. de an., a. 6 and ad. 2. “The act of existing (actus essendi) is the highest act in which all things can participate, but the act of existing itself does not participate in anything at all. And so if there is a being that is itself a subsisting act of existing (impsum esse subsistens), as we call God, we say that it does not participate in anything. But this is not the case with other subsisting forms, which necessarily participate in the act of existing itself and are related to it as potentiality to act.”

¹⁹ Wippel, pp. 132–76. Put simply, the creature is not identical with its existence but merely has existence. Thus, the essence exercises causality when it is co-created as “relative non-being” which limits the esse received to a certain mode of esse.

²⁰ Carroll, Warren, Creation in St. Thomas (Toranto : PIMS, 1997)Google Scholar; SCG II, c. 35, n. 4. “Et ideo, sicut effectus naturalis agentis sequitur esse agentis …”

²¹ De Pot., q. 3, a. 4. SCG III, c. 78; IV, c. 74.

²² ST III q. 62, a. 1, ad 2.

²³ SCG III c. 70.

²⁴ Velde, Rudi te, Participation and Substantiality (New York: Brill, 1995), p. 175CrossRefGoogle Scholar.

²⁵ Jordan, Mark D., “Theology and Philosophy,” in The Cambridge Companion to Aquinas, eds. Kretzmann, and Stump, (Cambridge: University Press, 1993), pp. 232–51CrossRefGoogle Scholar.

²⁶ Jordan, “Theology and Philosophy.” Cf. also SCG III, c. 70.

²⁷ Wawrykow, Joseph, “Jesus in the Moral Theology of St. Thomas,” in Journal of Medieval and Early Modern Studies 42.1 (2012), pp. 13–33. Cf. page 27.CrossRefGoogle Scholar

²⁸ United instruments can either be animate or inanimate. The only animate united instrument is the human nature of Christ. Certainly, according to Aquinas, Christ's human nature is ontologically united to his divine nature in the second person of the Trinity (without mixing). Inanimate united instruments are a harder category to identify. Indeed it seems that the body or the hands are animated precisely by the soul and would thus be animated conjoined instruments. Nevertheless, in themselves they are inanimate and only when used by the soul or the intention of the soul are they seen as instruments. Thus it seems right to identify them as inanimate conjoined instruments. They are inanimate in themselves (are not the principle of act).

²⁹ This is the only category that Wawrykow does not explicitly identify. Nevertheless, one could get such a category from Aquinas's texts such as SCG IV c. 41: “Now, the body and its parts are the organ of the soul in one fashion; external instruments in quite another. For this axe is not the soul's very own instrument, as this hand is, for by an axe many can operate, but this hand is deputy to this soul in its very own operation. For this reason the hand is an instrument of the soul united to it and its very own, but the axe is an instrument both- external and common.”

³⁰ SCG IV c. 41.

³¹ Super Sent., lib. 2 d. 18 q. 2 a. 3 ad 2: “Alio autem modo sequitur aliquid ex eis sicut ex instrumentis, ut dicit philosophus in 2 de anima, quod ignis in motu augmenti est sicut instrumentum regulatum, sed principaliter agens et regulans est virtus animae dirigens in determinatam quantitatem.”

³² SCG III C. 126 N. 2: “Again, since bodily organs are the instruments of the soul, the end of each organ is its use, as is the case with any other instrument;” SCG IV c. 33.

³³ ST I-II q. 18, a. 1, ad 2.

³⁴ This is implied by Aquinas's criticism of Plato for positing subsisting ideas apart from a mind. Cf. Doolan, pp. 192–195.

³⁵ ST I-II q. 15, a. 3, co.: “Respondeo dicendum quod, cum ideae a Platone ponerentur principia cognitionis rerum et generationis ipsarum, ad utrumque se habet idea, prout in mente divina ponitur. Et secundum quod est principium factionis rerum, exemplar dici potest, et ad practicam cognitionem pertinet. Secundum autem quod principium cognoscitivum est, proprie dicitur ratio; et potest etiam ad scientiam speculativam pertinere. Secundum ergo quod exemplar est, secundum hoc se habet ad omnia quae a Deo fiunt secundum aliquod tempus. Secundum vero quod principium cognoscitivum est, se habet ad omnia quae cognoscuntur a Deo, etiam si nullo tempore fiant; et ad omnia quae a Deo cognoscuntur secundum propriam rationem, et secundum quod cognoscuntur ab ipso per modum speculationis.”

³⁶ DV q. 3, a. 1; ST I q. 35, a. 1, ad 1.

³⁷ Doolan, 160–161.

³⁸ DV q. 3, a. 1, co; ST III q. 24, a. 3, ad 3: “the exemplified thing must conform to the exemplar according to the order of form.”

³⁹ ST I-II q. 9, a. 3, co. In this sense Kondoleon is right that the exemplar is a final cause. Cf. Kondoleon, pp. 158–60.

⁴⁰ Perrett, p. 462. Strictly speaking one may also divide between the finis operis and the finis operantis. A idea in the practical order is only a final cause as the finis operis not the finis operantis. Put simply, I intend to build a house for the sake of inhabiting. For the sake of inhabiting is the finis operantis whereas the house is the finis operis. The idea is the end of production not the end intended by the agent. Hence, strictly speaking the house is a means conceived in the act of counsel/deliberation and not the end intended by the will. It is only a final cause in an extended sense. Cf. DPD q. 3, a. 16, co.: “And although the form is the end of the operation, being the end that terminates the operation of the agent, nevertheless not every end is a form. For there is in the intention an end that is not the end of the operation, as in the case of a house. The form of the house is the end terminating the operation of the builder: but his intention does not terminate there but in a further end, namely a dwelling-place, so that the end of the operation is the form of a house, that of the intention, a dwelling-place.”

⁴¹ DPD q. 6, a. 3, ad 16.

⁴² Perrett, p. 461.

⁴³ DPD q. 6, a. 3, ad 3; VI meta. l. 1, n 1153; ST I q. 14, a. 8.

⁴⁴ X meta. l. 2, n. 1959; XII meta. l. 7, n. 2535.

⁴⁵ ST I-II q. 17, a. 1, co.

⁴⁶ ST I-II q. 9, a. 1.

⁴⁷ Reith, p. 156.

⁴⁸ SCG II c. 21, n. 6.

⁴⁹ ST I-II q. 62, a. 1, co.: “Et ideo aliter dicendum, quod duplex est causa agens, principalis et instrumentalis.”

⁵⁰ SCG II c. 21, n. 78 : “Now, the effect answering to an instrument's proper action is prior, in the order of productive process, to the effect corresponding to the principal agent.”

⁵¹ While this argument is conjectural vis-à-vis explicit texts, one might take SCG III c. 69, n. 23 as evidence: “Similiter etiam non oportet quod, quia omnis actio inferiorum corporum fit per qualitates activas et passivas, quae sunt accidentia, quod non producatur ex actione eorum nisi accidens. Quia illae formae accidentales, sicut causantur a forma substantiali, quae simul cum materia est causa omnium propriorum accidentium, ita agunt virtute formae substantialis. Quod autem agit in virtute alterius, producit effectum similem non sibi tantum, sed magis ei in cuius virtute agit: sicut ex actione instrumenti fit in artificiato similitudo formae artis. Ex quo sequitur quod ex actione formarum accidentalium producuntur formae substantiales, inquantum agunt instrumentaliter in virtute substantialium formarum.” Likewise, with DPD q. 3, a. 7, ad 7.

⁵² For St. Thomas's conception of the human act see Westburg, Daniel, Right Practical Reason: Aristotle, Action, and Prudence in Aquinas (Oxford: Clarendon Press, 1994)Google Scholar; Oesterle, John A., Ethics: The Introduction to Moral Science (New Jersey: Prentice-Hall, 1957)Google Scholar; Sherwin, Michael O.P., By Knowledge & By Love: Charity and Knowledge in the Moral Theology of St. Thomas Aquinas (Washington, D.C.: The Catholic University of America Press, 2005)Google Scholar; Bourke, Vernon J., Ethics: A Textbook in Moral Philosophy (New York: The Macmillan Company, 1951)Google Scholar; Rziha, John, Perfecting Human Actions: St. Thomas Aquinas on Human Participation in Eternal Law (Washington, D.C.: The Catholic University of America Press, 2009)Google Scholar.

⁵³ ST I-II q. 9, a. 1, co.

⁵⁴ The conjectural evidence for this argument is ST I-II q. 16, a. 1, co.: “The use of a thing implies the application of that thing to an operation: hence the operation to which we apply a thing is called its use; thus the use of a horse is to ride, and the use of a stick is to strike. Now we apply to an operation not only the interior principles of action, viz. the powers of the soul or the members of the body; as the intellect, to understand; and the eye, to see; but also external things, as a stick, to strike. But it is evident that we do not apply external things to an operation save through the interior principles which are either the powers of the soul, or the habits of those powers, or the organs which are parts of the body. Now it has been shown above that it is the will which moves the soul's powers to their acts, and this is to apply them to operation. Hence it is evident that first and principally use belongs to the will as first mover; to the reason, as directing; and to the other powers as executing the operation, which powers are compared to the will which applies them to act, as the instruments are compared to the principal agent. Now action is properly ascribed, not to the instrument, but to the principal agent, as building is ascribed to the builder, not to his tools. Hence it is evident that use is, properly speaking, an act of the will.”

⁵⁵ It might seem at first that this argument cannot avoid committing two fallacies. First, the fallacy of an illicit conversion of an A proposition by claiming that because it is the very essence of an instrument to be moved that all moved things are instruments. Likewise, it seems that one cannot argue for this either. The following argument: all instruments are moved things, X is a moved thing, therefore X is an instrument is invalid (undistributed middle). Nevertheless, the argument is neither of the above. It is: all exemplars are that which cause when moved; all things that cause when moved are instruments; thus, all exemplars are instruments.

⁵⁶ ST I-II q. 9, a. 1, ad 3: “Ad tertium dicendum quod voluntas movet intellectum quantum ad exercitium actus, quia et ipsum verum, quod est perfectio intellectus, continetur sub universali bono ut quoddam bonum particulare. Sed quantum ad determinationem actus, quae est ex parte obiecti, intellectus movet voluntatem, quia et ipsum bonum apprehenditur secundum quandam specialem rationem comprehensam sub universali ratione veri. Et sic patet quod non est idem movens et motum secundum idem.”

⁵⁷ ST I-II q. 16, a. 1, co. & ad 3; DV q. 5, a. 10, co.: “and the characters of the good and of an end primarily pertain to the will, which uses everything we have as instruments toward achieving our end.” Cf. Brock, Stephen, “What is the Use of Usus in Aquinas’ Psychology of Action?,” in Moral and Political Philosophies in the Middle Ages, eds. Bazán, B., Andújar, E., Sbrocchi, L., vol. II (Ottawa: Legas, 1995), pp. 654–64Google Scholar.

⁵⁸ Brock, 660: “The ensuing act of use is his first actively undertaking the real performance of that kind of action, by setting the appropriate instruments to work.”

⁵⁹ There seem to be two separate questions here: whether instruments must always be efficient and whether instruments must always be in the same species of causality as their primary agent. An affirmative answer to the first would posit an odd conception in which God used us as instruments only in the efficient order. ST I-II q. 62, a. 1, co. certainly identifies instruments as functioning in the efficient order, but even in that article (whose context is concerned with efficient production of grace) has germs of the opposite opinion. “Hoc autem proprie dicitur instrumentum, per quod aliquis operatur.” That through which another operates does not necessarily have to be efficient. Likewise, in this article the idea in the mind of the agent is located as the principle agent and the saw the instrumental. Certainly then categories can be crossed in instrumentality according to Aquinas.

⁶⁰ DV q. 4, a. 1, ad 4: “Ad quartum dicendum, quod medium quod accipitur inter terminos motus, aliquando accipitur secundum aequidistantiam terminorum, aliquando autem non. Sed medium quod est inter agens et patiens, si sit quidem medium, ut instrumentum, quandoque est propinquius primo agenti, quandoque propinquius ultimo patienti; et quandoque se habet secundum aequidistantiam ad utrumque; sicut patet in agente cuius actio ad patiens pervenit pluribus instrumentis. Sed medium quod est forma qua agens agit, semper est propinquius agenti, quia est in ipso secundum veritatem rei, non autem in patiente nisi secundum sui similitudinem. Et hoc modo verbum dicitur esse medium inter patrem et creaturam. Unde non oportet quod aequaliter distet a patre et creatura.”

⁶¹ Doolan, pp. 173–175. I owe a special thanks to Dr. Doolan for whose class this paper was written and whose comments on it were indispensable.