Subordinated Causality as Illustration of Philosophy's Service to Theology


By Taylor Patrick O’Neill, Ph.D.

Philosophy at the Service of Theology

AT the heart of St. Thomas’ theory of knowledge is the fundamental truth that reality is one. While individual sciences may differ in the object of their study, these various objects come together to compose a single reality, the organized and intelligible cosmos. In this way, St. Thomas is able to maintain that philosophy and theology, while distinct, are capable of what Pope Benedict XVI called “mutual and advantageous collaboration.”[1] St. Thomas called Averroes the “perverter of Peripatetic philosophy”[2] since he maintained that theological and philosophical truths could be at odds with one another.[3] On the contrary, St. Thomas states: “Since, therefore, only the false is opposed to the true, as is clearly evident from an examination of their definitions, it is impossible that the truth of faith should be opposed to those principles that the human reason knows naturally.”[4] Philosophy may thus act as a handmaiden of theology (ancilla theologiae), providing it with truths known via human reason such that it might better understand the truths that are above human reason and revealed by God. St. Thomas utilizes the philosophical thought of the Greeks, particularly Aristotle, to help us better understand what we hold by faith.

Subordinated Causality

  There is a plethora of examples of the service which philosophy provides to theology. Perhaps one of the best examples is the concept of subordinated causality. This scholastic theory, drawing upon Aristotle,[5] posits a subordinated relationship between two causes, one which is primary and the other which is secondary or instrumental. Bernard Wuellner, S.J. in Dictionary of Scholastic Philosophy defines the primary or principle cause as, “a cause which works by the power of its own form…” while a secondary cause is defined as “a cause under and dependent upon the first cause… a cause that can only specify the kind, but not the being of the effect.”[6] In other words, the secondary cause truly causes some effect but only if it is first moved by the primary cause to cooperate in bringing about that effect. In this way, the primary cause is more properly the cause of the effect but it works through the secondary cause such that we can attribute the effect fully to both causes.

Subordinated causality can be contrasted with coordinated causality wherein two or more causes work together, side-by-side, as it were, such as when two men row a boat. Two men rowing a boat work together, with each man providing roughly fifty percent of the work needed to move the boat forward. With subordinated causality, we would not say that the primary and secondary cause each provide fifty percent of the causality of a given effect but rather that the primary cause brings about the entirety of the effect through the secondary cause. Rather than two men rowing a boat, an example of subordinated causality might be that of a father taking the hand of his child to help him write his name.

Two Extremes to be Rejected

  In general, this principle of subordinated causality is related to God insofar as God is the most primary or principal cause of all existence. Utilizing this principle allows us to reject two extremes regarding the relationship between God’s causality and the causality of lower things (be they people, the sun, electricity, etc.): occasionalism and divine passivity.

            Occasionalism holds that God is the only true cause at work in the cosmos. While this may seem absurd on the surface, this theory has been held by important and influential minds including Nicolas Malebranche and Muslim philosopher theologians Al-Ghazali and Al-Ashʿari. St. Thomas describes this theory as follows, “…some men have taken the opportunity to fall into error, thinking that no creature has an active role in the production of natural effects. So, for instance, fire does not give heat, but God causes heat in the presence of fire, and they said like things about all other natural effects.”[7] St. Thomas objects to this theory on numerous grounds, stating, “…if created things could in no way operate to produce their effects, and if God alone worked all operations immediately, these other things would be employed in a useless way by Him, for the production of these effects. Therefore, the preceding position is incompatible with divine wisdom,”[8] and “Therefore, if He has communicated His likeness, as far as actual being is concerned, to other things, by virtue of the fact that He has brought things into being, it follows that He has communicated to them His likeness, as far as acting is concerned, so that created things may also have their own actions.”[9]

            Of course, the opposite extreme from occasionalism would posit that God is completely passive in the execution and operation of His own created order. If He were not causally involved in the created order then all effects and motions which make up that order would be brought about solely by created causes. God would hold no providential control. And yet, St. Thomas, drawing upon Sacred Scripture, teaches that, “all things are subject to divine providence, not only in general, but even in their own individual selves.”[10] St. Thomas condemns those who hold that any aspect of the created order is the result of blind chance stating, “the ancient philosophers of nature are refuted, for they said that all things come about as a result of material necessity, the consequence of which would be that all things happen by chance and not from the order of providence.”[11]

            In order to find the mean between these two extremes, we must employ the philosophical notion of subordinated causality. Secondary, created causes are neither illusions nor are they independent of God’s causality and control. St. Thomas states that, “divine operation does not exclude the operations of secondary causes. But the resultants of the operations of secondary causes are within the scope of divine providence, since God orders all singulars by Himself, as we showed. Therefore, secondary causes are the executors of divine providence.”[12] Secondary causes are true causes and yet, insofar as they are subordinate and contingent upon God as first cause, God maintains an exhaustive providential control over the entirety of creation.[13] St. Thomas says, “Therefore, we do not take away their proper actions from created things, though we attribute all the effects of created things to God, as an agent working in all things.”[14] This philosophical proposition allows theology to adequately answer numerous challenging questions.

Subordinated Causality and Human Freedom

There is perhaps no theological question more demanding or controversial than the relation between divine causality and human freedom, and while a full consideration of that question would be well beyond the scope of this little essay, we can at least see how the concept of subordinated causality permits the theologian to maintain both divine government of human actions and their truly free character.

            St. Thomas maintains that God moves the will of the free creature but that this providential movement can move and cause in varying ways. It can move or cause of necessity or it can move and cause a thing to happen contingently, i.e. without absolute necessity.[15] God’s grace indeed moves us to some good action, but God works providentially upon the will in such a way that He preserves our free choice of that action.[16] In a real way, we are not simply moved to x deed as a robot programmed for operation; rather, we cooperate and participate in our willing x as a secondary and subordinated cause.  Thus, the theologian can maintain the primacy of grace and divine causality without robbing man of the dignity of being a free creature . It is this which differentiates him from mere animals and which is the source of the very possibility of his merit and eternal life.

Subordinated Causality and the Authorship of Scripture

  Following upon this, it is not difficult to imagine how the theologian might make sense of the authoring of the Sacred Scriptures. In what way can Scripture be called the Word of God if it was written by human authors? Is the theologian required to maintain that God takes possession of their intellect in order that He may override their will so as to maintain His own divine authorship?

Once again, these difficulties can be answered only with advertence to subordinated causality. Scriptural authorship paints a picture, as it were, of the rich and beautiful cooperation in salvation history which man is gifted by God. Dei verbum states, “In composing the sacred books, God chose men and while employed by Him they made use of their powers and abilities, so that with Him acting in them and through them, they, as true authors, consigned to writing everything and only those things which He wanted.”[17] In this way, we can both recognize the words of Sacred Scripture as entirely coming from God and yet also being marked, if you will, by the “styles of feeling, speaking, and narrating” of the human authors.[18]

Subordinated Causality and the Sacraments

  Finally, subordinated causality allows the theologian to better understand the way in which the sacraments confer grace. For Protestant reformers like Martin Luther, there was a concern that the sacraments had come to be viewed as a kind of incantation or magic. In response, his sacramental theology rejects the idea that the sacraments themselves act as causes of grace.[19] Of course, the Church rejects this view since it robs the sacraments of their causality, necessitating that they act as mere signs of a grace given alongside but quite apart from the sacraments themselves. Rather, the Church teaches that the sacraments work ex opere operato. They are themselves efficient causes of grace. The Council of Trent affirms this over and against Luther’s theology of the sacraments, stating:

If any one saith, that the sacraments of the New Law do not contain the grace which they signify; or, that they do not confer that grace on those who do not place an obstacle thereunto; as though they were merely outward signs of grace or justice received through faith, and certain marks of the Christian profession, whereby believers are distinguished amongst men from unbelievers; let him be anathema.[20]


If any one saith, that by the said sacraments of the New Law grace is not conferred through the act performed, but that faith alone in the divine promise suffices for the obtaining of grace; let him be anathema.[21]

Does this, in turn, neuter the primacy of God as the sole source of grace? St. Thomas’ advertence to subordinated causality again provides the way forward. He says:

Those who hold that the sacraments do not cause grace save by a certain coincidence, deny the sacraments any power that is itself productive of the sacramental effect, and hold that the Divine power assists the sacraments and produces their effect. But if we hold that a sacrament is an instrumental cause of grace, we must needs allow that there is in the sacraments a certain instrumental power of bringing about the sacramental effects.[22]

Of course, if sacramental causality is instrumental, this necessitates a higher and more primary cause which utilizes the sacraments as instrumental causes. These causes are fundamentally contingent upon the primary cause for any causality which they have. The primary cause of sacramental grace is God Himself, as St. Thomas states. “Just as an instrumental power accrues to an instrument through its being moved by the principal agent, so does a sacrament receive spiritual power from Christ's blessing and from the action of the minister in applying it to a sacramental use.”[23] Moreover, “Now the principal efficient cause of grace is God Himself… whereas the sacrament is as a separate instrument. Consequently, the saving power must needs be derived by the sacraments from Christ's Godhead through His humanity.”[24] The sacraments acting as subordinated, instrumental causes of grace in no way take away from the sovereignty of God as exclusive origin and author of that grace.


            As we can see, the philosophical principle of subordinated causality is at the heart of many theological doctrines, including those which safeguard God’s primacy of governance and grace alongside true human and sacramental cooperation in that sovereignty. This ought to suffice to illustrate the indispensable assistance which theology requires from the properly philosophical science. Moreover, this particular philosophical insight of subordinated causality gives the Christian much to contemplate regarding how God governs the world and the special place which man has in the unfolding of the divine work of that world. This has been beautifully considered by J.R.R. Tolkien:


Disgraced he may be, yet is not dethroned,

and keeps the rags of lordship once he owned,

his world-dominion by creative act:

not his to worship the great Artefact,

man, sub-creator, the refracted light

through whom is splintered from a single White

to many hues, and endlessly combined

in living shapes that move from mind to mind.

Though all the crannies of the world we filled

with elves and goblins, though we dared to build

gods and their houses out of dark and light,

and sow the seed of dragons, 'twas our right

(used or misused). The right has not decayed.

We make still by the law in which we're made.[25]


[1] Pope Benedict XVI, General audience from June 16, 2010.

[2] St. Thomas Aquinas, De unitate intellectus contra Averroistas, Chapter 2, §59.

[3] Ibid., chapter 5, §123: “Adhuc autem gravius est quod postmodum dicit: per rationem concludo de necessitate, quod intellectus est unus numero; firmiter tamen teneo oppositum per fidem. Ergo sentit quod fides sit de aliquibus, quorum contraria de necessitate concludi possunt. Cum autem de necessitate concludi non possit nisi verum necessarium, cuius oppositum est falsum impossibile, sequitur secundum eius dictum quod fides sit de falso impossibili, quod etiam Deus facere non potest: quod fidelium aures ferre non possunt. Non caret etiam magna temeritate, quod de his quae ad philosophiam non pertinent, sed sunt purae fidei, disputare praesumit, sicut quod anima patiatur ab igne Inferni, et dicere sententias doctorum de hoc esse reprobandas. Pari enim ratione posset disputare de Trinitate, de incarnatione, et de aliis huiusmodi, de quibus nonnisi caecutiens loqueretur.”

[4] ScG, Chapter 7, §1: “Quia igitur solum falsum vero contrarium est, ut ex eorum definitionibus inspectis manifeste apparet, impossibile est illis principiis quae ratio naturaliter cognoscit, praedictam veritatem fidei contrariam esse.”

[5] See, for example, Metaphysics, II, Chapter 2, §153: “For intermediate things in a series limited by some first and last thing must have as their cause the first member of the series, which they follow; because if we had to say which one of these three is the cause of the others, we would say that it is the first. What is last is not the cause, since what is last is not a cause of anything. Neither is the intermediate the cause, because it is the cause of only one; for it makes no difference whether one or several intermediates exist, or an infinite or finite number. Indeed, in series that are infinite in this way or in the infinite in general, all parts are intermediates to the same degree right down to the present one. Therefore, if there is nothing first in the whole series, nothing in the series is a cause.”

[6] Bernard Wuellner, S.J., Dictionary of Scholastic Philosophy (Milwaukee: The Bruce Publishing Company, 1956), 19.

[7] ScG III, Chapter 69, §1: “Ex hoc autem quidam occasionem errandi sumpserunt, putantes quod nulla creatura habet aliquam actionem in productione effectuum naturalium: ita scilicet quod ignis non calefacit, sed Deus causat calorem praesente igne; et similiter dicunt in omnibus aliis effectibus naturalibus.”

[8] Ibid., §13: “Si autem res creatae nullo modo operarentur ad effectus producendos, sed solus Deus operaretur omnia immediate, frustra essent adhibitae ab ipso aliae res ad producendos effectus. Repugnat igitur praedicta positio divinae sapientiae.”

[9] Ibid., §14: “Si igitur communicavit aliis similitudinem suam quantum ad esse, inquantum res in esse produxit, consequens est quod communicaverit eis similitudinem suam quantum ad agere, ut etiam res creatae habeant proprias actiones.”

[10] ST I, q. 22, a. 2: “…omnia divinae providentiae subiacere, non in universali tantum, sed etiam in singulari”.

[11] ScG III, Chapter 65, §13: “…excluditur error antiquorum naturalium, qui dicebant omnia ex necessitate materiae provenire: ex quo sequebatur omnia casu accidere, et non ex aliquo providentiae ordine.”

[12] Ibid., Chapter 77, §2: “Ostensum est supra quod divina operatio non excludit operationes causarum secundarum. Ea vero quae ex operationibus causarum secundarum proveniunt, divinae providentiae subiacent: cum Deus omnia singularia ordinet per seipsum, ut ostensum est. Sunt igitur secundae causae divinae providentiae executrices.”

[13] Ibid., Chapter 94.

[14] Ibid., Chapter 69, §29: “Non igitur auferimus proprias actiones rebus creatis, quamvis omnes effectus rerum creatarum Deo attribuamus quasi in omnibus operanti.”

[15] See SCG III, Chapter 73 and ST I, q. 19, a. 8.

[16] ScG III, Chapter 90, §3 – 4: “Again, all corporeal things are governed through spiritual beings, as we showed above. But spiritual beings act on corporeal things through the will. Therefore, if choices and movements of the wills of intellectual substances do not belong to God’s providence, it follows that even corporeal things are withdrawn from His providence. And thus, there will be no providence at all.

Besides, the more noble things are in the universe, the more must they participate in the order in which the good of the universe consists. So, in Physics II [4], Aristotle accuses the ancient philosophers of putting chance and fortune in the make-up of the celestial bodies, but not in things below. Now, the intellectual substances are more noble than bodily substances. Therefore, if bodily substances, in their substances and actions, fall under the order of providence, so do intellectual substances, for a greater reason.”

“Item. Quanto aliqua sunt nobiliora in universo, tanto oportet quod magis participent ordine, in quo bonum universi consistit. Unde Aristoteles, in II Phys., arguit antiquos philosophos, qui ponebant casum et fortunam in constitutione caelestium corporum, non autem in inferioribus rebus. Substantiae autem intellectuales sunt nobiliores substantiis corporalibus. Si ergo substantiae corporales, quantum ad suas substantias et actiones, cadunt sub ordine providentiae, multo magis substantiae intellectuales.        

Praeterea. Ea quae sunt propinquiora fini, magis cadunt sub ordine qui est ad finem: nam eis mediantibus etiam alia ordinantur in finem. Actiones autem substantiarum intellectualium propinquius ordinantur in Deum sicut in finem, quam actiones aliarum rerum, sicut supra ostensum est. Magis igitur cadunt actiones intellectualium substantiarum sub ordine providentiae, qua Deus omnia in seipsum ordinat, quam actiones aliarum rerum.”

[17] Dei verbum, §11.

[18] Ibid., §12.

[19] Martin Luther, Augsburg Confessions, Article 13. There Luther says that the sacraments are merely “signs and testimonies of the will of God toward us, instituted to awaken and confirm faith in those who use them” and that they should be condemned “who teach that the Sacraments justify by the outward act.”

[20] The Council of Trent, Session VII (March 6, 1547), canon 6.

[21] Ibid., canon 8.

[22] ST III, q. 62, a. 4: “Respondeo dicendum quod illi qui ponunt quod sacramenta non causant gratiam nisi per quandam concomitantiam, ponunt quod in sacramento non sit aliqua virtus quae operetur ad sacramenti effectum, est tamen virtus divina sacramento coassistens, quae sacramentalem effectum operatur. Sed ponendo quod sacramentum est instrumentalis causa gratiae, necesse est simul ponere quod in sacramento sit quaedam virtus instrumentalis ad inducendum sacramentalem effectum.”

[23] Ibid., ad 3: “Sicut virtus instrumentalis acquiritur instrumento ex hoc ipso quod movetur ab agente principali, ita et sacramentum consequitur spiritualem virtutem ex benedictione Christi et applicatione ministri ad usum sacramenti.”

[24] Ibid., a. 5: “Principalis autem causa efficiens gratiae est ipse Deus…sacramentum autem sicut instrumentum separatum. Et ideo oportet quod virtus salutifera derivetur a divinitate Christi per eius humanitatem in ipsa sacramenta.”

[25] J.R.R. Tolkien, Mythopoeia: To one who said that myths were lies and therefore worthless,

even though "breathed through silver.”