Introduction
Analytical natural theology normally exhibits what David Twetten has described as a ‘Religious Standard Approach’.Footnote 2 The core of such approach is the following assumption:
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(1) Religious approach: Arguments for the existence of God must be regarded as an attempt to defend the existence of the God of classical theism, and therefore the only successful proofs are those arguments that conclude in a God satisfying all the descriptions present in mainstream religious traditions, or at least most of them.
There are some good reasons to adopt such an approach. After all, is not the God of monotheistic religions what theists normally want to defend and atheists insist on denying? Why bother to prove or disprove the existence of a ‘God’ nobody believes on? Unfortunately, there are also good reasons to be sceptical of this enterprise. Those searching for religious answers will discover that the ‘God’ resulting from philosophical syllogisms is disappointingly cold and distant. Assuming that ‘God’ is the proper name of an individual with whom we get acquainted in Revelation makes the identification phase of cosmological arguments simply hopeless.Footnote 3
The religious approach often distorts our reading of some traditional authors. As Nicholas Wolterstorff has correctly noted, the apologetic task of persuading an open-minded atheist by providing rational evidence for theistic beliefs is alien to the true spirit that inspired medieval natural theology.Footnote 4 A typical example are the proofs of God's existence that Thomas Aquinas proposes at the beginning of his Summa Theologiae.Footnote 5 These arguments do not aim to establish the truth of classical theism by pointing the logical-deductive link between ‘God exists’ and other propositions a ‘standard atheist’ should be willing to accept.Footnote 6 Nor is it the concern of Aquinas to increase the level of warrant or rational justification for the theistic hypothesis by providing purely rational (i.e., not faith-based at all) arguments for the belief in God. Of course, there is nothing wrong with the rigorous philosophical exposition and evaluation of such arguments as The Five Ways, nor with the eventual employment of the arguments of natural theology within an apologetic context. But this would be a creative reappropriation of Aquinas’ thought, not an exposition of it.Footnote 7
Instead of (1), the approach of the five ways is described by Twetten as ‘non-prescriptive’:Footnote 8
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(2) Non-prescriptive approach: Natural theology does not presuppose a demanding prior definition that establishes the conditions an argument's conclusion must fulfill in order to be considered a proper demonstration of God's existence.
This allows natural theology to employ a plurality of definitions of ‘God’, resulting from the very plurality of the arguments that prove God's existence. The success of the arguments does not depend on its apologetic power, because they are not primarily supposed to induce religious belief. In the context of Aristotelian sciences, natural theology is a part of metaphysics, and as such aims towards theoretical justification but not necessarily towards rhetoric persuasiveness.
Aquinas' project makes more sense when read from this perspective. Instead of reinforcing The Five Ways with successive demonstrations of the divine attributes and suspending judgement about their demonstrative power until enough of them have been successfully proven, we should see natural theology as a very broad research program where the arguments are allowed to speak by themselves. Our aim can simply be to develop a systematic account of the ultimate cause of our universe, based on the very result of some initial arguments that demonstrate the necessity of positing the existence of such a cause. By determining God's explanatory role within our ontology, proofs of God's existence stablish a connection between our ordinary experience of nature and our comprehension of the supernatural as its ultimate ground. In Aquinas' philosophy, the basic and systematic sketch for this program that bestows a natural knowledge of God is triplex via, the ascension from creatures to God through the threefold path of causation, negation, and eminence.
Regarding faith-based definitions of God, these are always in the background, as an implicit and external guidance. As a matter of fact, philosophical reflection is also providing a novel guidance for the interpretation and greater intelligibility of religious beliefs, and for this reason it could be said that the main function natural theology has for a believer is semantic and hermeneutic. Only looking back retrospectively, The Five Ways that opened the Summa might seem for a believer to be evidence for the truth of classical theism. But isolating the ways from this bigger metaphysical framework and regarding them alone as self-sufficient proofs of theism from the very beginning is moving beyond the scope of Aquinas’ text and engaging in bad apologetics.
The following pages will try to sketch this structure of a natural theology inspired in the texts of Aquinas.Footnote 9 The first section will present the so called ‘Gap Problem’ objection that frequently presents in the religious approach. The second section develops the importance of the triplex via as the basic scheme for Aquinas’ account of ‘God’. A final section will discuss how triplex via can help to overcome the potential difficulty of the ‘Gap problem’ by placing the ways in the context of a wider philosophical inquiry.
I. A ‘Gap Problem’?
A common objection to The Five Ways is the so-called ‘gap problem’, which could be presented as follows:
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(3) Gap problem: Even if cosmological arguments successfully establish the existence of a Necessary Being or First Cause, it is unclear whether this result coincides with what theists usually mean by ‘God’.
I borrow this expression from Alexander Pruss,Footnote 10 who in turn attributes it to Richard Gale. I am also taking the liberty of describing Aquinas’ ways as ‘cosmological arguments’, even though some Thomistic authors, such as Joseph Owens,Footnote 11 express reservations about this. The Five Ways obviously differ in many respects from the Leibnizian argument that Kant famously criticized, but there are still sufficient similarities to accept their description as ‘cosmological’ in a broad sense.
A common strategy to defend Aquinas against (3) is to incorporate in the argument the immediately following quaestiones, where Aquinas gradually argues for the divine attributes of traditional theism. Twetten calls this additional step of the argument the ‘identification stage’, and describes the strategy as a ‘total package defense’:Footnote 12
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(4) Total package defense: The successfulness of cosmological arguments requires that additional arguments be given in order to show that the Necessary Existent fulfills at least some of the descriptions of God commonly held by classical theism.
One of the most notable applications of this strategy belongs to Norman Kretzmann, according to whom Aquinas would achieve his goal gradually. To show this, his commentary on the Summa Contra Gentiles provisionally invites us to name the immediate result of the Thomistic ways ‘Alpha’, and then see how the development of Alpha's attributes by Aquinas make it increasingly resemble the theistic God.Footnote 13 Twetten also cites as adherents of this approach William L. Rowe and William L. Craig, for whom the conclusion that God exists is only reached in ST I q.11.Footnote 14 We could also include John Wippel in this category, since he considers the Thomist ways an incomplete argument unless we attach to them a demonstration of the uniqueness of God (which in turn presupposes Aquinas’ previous treatment of God's entitative attributes).Footnote 15 Pruss will also follow this route.Footnote 16
From an exegetical point of view, this strategy seems somewhat forced. Aquinas says that the demonstration of God's existence is dealt with specifically in ST I q.2, and at no point does he suggest reserving judgment regarding success or failure of the arguments until later. There appears to be no textual basis for claiming, as Wippel suggests, that Aquinas ‘realized that without this additional argumentation his proof that God exists would not be complete’.Footnote 17
A more careful consideration of Kretzmann's interpretation could be useful. He titles the project in general as a ‘metaphysics of theism’, which shows that he has in mind something broader than just arguments intended to increase the rational justification of theistic beliefs. He also compliments Wolterstorff's point regarding the difference between medieval natural theology and evidentialist apologetics.Footnote 18 Kretzmann knows that SCG is not designed to meet the objections of hypothetical non-believers but an attempt to show how the truths of faith are in harmony with those achieved by philosophical reason, providing argumentative clarification and confirmation for Christian doctrine.Footnote 19 However, Kretzmann distinguishes between a heuristic natural theology (typical of pagan philosophers, who wanted to use natural reason to discover the truth about God), and an expositional one (which works under the influence of religion and seeks the systematic presentation of the truth about God and everything concerning Him), the latter being what Aquinas does.Footnote 20 Kretzmann will later conclude that this expositional project fails, since the arguments offered in SCG I 13 are not conclusive demonstrations of the existence of the God of classical theism. Therefore, he will argue that we must give up natural theology as Aquinas understood it, and instead of beginning by proving the existence of ‘God’ think in terms of an ‘ultimate explanatory principle’, inquiring into its nature (the attributes it should have) and only at the end returning to the problem of God's existence.Footnote 21
In my opinion, Aquinas view of natural theology is always heuristic, and if SCG adopts what Kretzmann calls an expositional perspective this is so just because it is not strictly a treatise on natural theology. Nevertheless, from the very beginning, and consistently through all of SCG I, Aquinas will consider God as an ‘ultimate explanatory principle’. Only by the end of each chapter, once the main point has been stablished by philosophical argumentation, Aquinas will quote some passages of Scripture that seem to be in harmony with the results of the inquiry. The alleged need to suspend judgement about the arguments for the existence of God and return to this problem by the end of the process only makes sense when one wants to evaluate whether or not the resulting natural theology increases the degree of justification that certain religious beliefs would have, or if this metaphysical proposal outweighs an eventual atheistic metaphysics. But this is not part of natural theology itself, it is an apologetical retrieval of the results of natural theology.
II. Triplex Via as a Systematic Proposal for an Account of ‘God’
This forces us to consider what I call the semantic and hermeneutic functions of natural theology. Aquinas’ Five Ways allow us to fix the referent for the word ‘God’; they can be taken as a rational basis for speaking intelligibly about the divine source of creation. And this semantic dimension is not a mere ad hoc resource that falls into oblivion once the referent of the word has been established. Rather, the entire Thomistic discussion of divine attributes is conditioned by it; our knowledge of the divine essence must be developed over the horizon that the ways have opened.
Aquinas undertakes the task of giving an account of the divine attributes through what he called the triplex via (threefold path). In short, Aquinas says that ‘from the divine effects we cannot know the divine nature as it is in itself, so as to know what it is; but only by way of eminence, and of causality and of negation’ (ST I q.13, a.8, ad 2). What he means by that is slightly more elaborated on in this other quote:
We know about God His relationship to creatures (insofar as He is the cause of them all); and also that creatures differ from Him (insofar as He is not one of those things caused by him), and that creatures are not separated from Him by reason of any defect on His part, but because He superexceeds them
(ST I q.12 a.12).Aquinas thinks that this approach is grounded in natural reason, and, therefore, it can allow a meaningful communication between a Christian believer and a pagan: ‘Neither the catholic nor the heathen know the very nature of God as it is on itself, but both of them know it according to some notion of causality or excellence or remotion’ (ST I q.13 a.10 ad 5).
Here we confront a formula taken from Pseudo-Dionysus that Aquinas re-elaborated and repeated numerous times in his works.Footnote 22 Triplex via offers the following systematic program for the development of natural theology:
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(5) Hermeneutic program of triplex via: Beginning by the demonstration of the existence of God, we can move forward to an account of the divine nature by attributing to God (i) predicates that express His causal action towards creatures (via causalitatis); (ii) negative predicates that express His separation or transcendence from the produced effects (via remotionis or via negationis); (iii) eminent predicates expressing the superlative preexistence of all created perfections in the uncreated essence of God (via eminentiae).
This methods of causality, removal, and eminence might even be a particularly interesting contribution of the Thomistic reflection to contemporary discussion, since it has the peculiarity of providing a systematic procedure for the philosophical determination of the divine attributes, beginning from the explanatory function God fulfills towards created reality. The itinerary taking us from the demonstration that God exists towards the conceptual articulation of divine attributes is precisely that of this interrelation between causality, eminence, and removal.
II.A. Triplex Via as an Intertwined Whole: The Grounding Place of Via Causalitatis
The order in which Aquinas states the three parts of the triplex via is not always uniform. Some consider that this somewhat variable way of presenting it may suggest a flexible use,Footnote 23 and this seems especially compelling when considering those texts where the three paths seem to function as independent routes to establish a certain truth about God (e.g., SSPL I d.35 q.1 a.1).
However, there are also many texts where the triplex via functions as an integral whole, as three steps or moments for the discursive process of conceiving God, intertwining and mutually dependent. For example, Aquinas claims in De Potentia (q.7 a.5 ad 2) that knowledge must be successively affirmed of God as the cause of all wisdom, denied inasmuch as it is not in God according to the way in which this attribute is understood by us, and once again eminently affirmed inasmuch as there is not absence of wisdom but perfect science in God. Also, in his exposition on De Trinitate, Aquinas identifies the three moments as interconnected movements in the discursive process through which the knowledge of God is deepened:
Therefore, the human mind grows in the knowledge of God in a threefold way, though it can never attain a knowledge of what He is, but only knowledge that He is. First, knowledge of God grows as a more perfect knowledge of His efficacy in the production of things is attained. Second, inasmuch as the nobler effects of the Cause are known, since by resembling Him those effects manifest His eminence more than others. Thirdly, knowledge of God grows as He is recognized as more and more afar from all the things that appear in his effects. Hence Dionysius said in De Divinis Nominibus that God is known as the cause of all things, exceeding them all and separated from them all
(SBT I q.1 a.2).Footnote 24In particular, the global account of the divine attributes developed in ST I qq. 3 to 26 will show how the three moments of the triplex via are systematically related in the progressive development of the divine attributes. The nature of this systematic intertwining comes to light when considering the order Aquinas frequently uses to present them. Attempts have been made to show systematic reasons for the changes in the expository order of triplex via. Michael Ewbank examines several texts, explaining that, in each case, it is the context what justifies the order Aquinas is using.Footnote 25 This author shows convincingly that, whenever Aquinas begins with via negationis, the existence of God has been presupposed.Footnote 26 He also shows clearly that the vast majority of texts place the via causalitatis first, a trend especially marked in ST and SCG, which are precisely those works where Aquinas is carrying out a systematic development of divine attributes based on the result of the arguments initially used to prove the existence of God.Footnote 27 On the other hand, those texts in which he begins by negation are generally early ones, or are commentaries to other texts where this order is employed.
Why this priority of causation? Keep in mind the sort of discursive process that we have sketched here. Natural theology leads us from the knowledge of creatures to that of the Creator, achieving first His existence and then, indirectly and very imperfectly, some of His attributes. Our account of ‘God’ must follow from the demonstrations; they must be their development.
There is a text where Aquinas expressly links via causalitatis with the answer to the question an sit:Footnote 28 Humans know God through causality because, ‘since creatures are defective and changeable, it is necessary to trace them back to some immutable and perfect principle. And according to this, it can be known that God exists’ (Super Epistolam B. Pauli ad Romanos ch.1 l.6). Aquinas’ famous ways to prove this are nothing but a formalized philosophical development of the ascent from the insufficiency of creatures to their ultimate foundation in the Creator, that is, an account of the via causalitatis, and accordingly, the gateway to further discourse on divinity.
The only place where Aquinas begins with eminence seems to be ST I q.13 a.8 ad 2. This exception is very interesting for our purposes, because it figures precisely where Aquinas is talking about what people ordinarily intend when they use the word ‘God’. Does this mean that, despite the priority that via causalitatis acquires on a systematic metaphysical context, Aquinas recognizes that in natural religiosity the sense of God's eminentia is more fundamental? Strictly speaking, that with which Aquinas associates the primordial sense of God in ordinary experience is God's provident care over all things, according to the spurious etymology he has taken from Damascene. This seems to be an experience where the sense of eminence and divine causality over the world are intimately linked. Providence presupposes our dependence on God, but considers it from the perspective of the wisdom and benevolence by which divinity governs nature. It can then be said that the eminence exhibited in providence is particularly dominant in the level of religious belief and the obscure pre-philosophical natural understanding of ‘God’. However, in the systematic development of natural theology that aims to give those beliefs intelligibility, it is necessary to give priority to the underlying causal relationship.
II.B. The Dialectic Between Denial and Eminence in Aquinas’ Account of Divine Attributes
Negatio and eminentia should be seen as a backflip of causalitas: The principle of causality essential to Aquinas’ ways demands that God be separated from His effects, and the principle of causal similitude demands perfections to be pre-existing eminently in Him. Indeed, the structure of the treatise on Deo Uno in ST exhibits what Rudi Te Velde describes as a ‘dialectic between simplicity and perfection’,Footnote 29 precisely corresponding to this pattern. In The Five Ways, Aquinas has come to identify God as the cause of creatures (via causalitatis, treated in q. 2), then remove from God all the forms of composition observed of creatures (via negationis: the ‘divine simplicity’, treated in q. 3), and finally affirm the eminent and completely unified pre-existence of all created perfections in God (via eminentiae: the ‘divine perfection’, discussed in q.4). The other entitative attributes (goodness, infinity, omnipresence, immutability, eternity, and unity) progressively elaborate the notion of God over the basis of these first two. Something similar occurs, more explicitly, in SCG I, where Aquinas begins with the existence of God (chaps. 10–13), introduces a methodological chapter on the importance of the via negationis (ch. 14), develops various negative predicates (chaps. 15–27), and immediately after introducing the first positive attribute (ch. 28: divine perfection), provides a new methodological section on the analogical similarity between God and creatures (chaps. 29–36), and then continues with the positive predicates (ch. 37 et seq.).
II.C. Via negationis as a Backflip of Via Causalitatis
The use of via negationis here seems different from Dionysus’ use. It is not primarily a mystical path that seeks to highlight God's absolute otherness (though the mystical dimension is neither completely absent,Footnote 30) but rather the simple fact that, being the cause of all things, God cannot be identified with any of them—it is integral to the enterprise of intelligibly expressing the cause from its relationship with the effect.Footnote 31 This negative aspect is quite marked in the ways, since the arguments clearly demand God to be immobile, uncaused, infinite, etc. In any case, the radicality of God's causal action over creatures also entails a great radicality in this divine otherness, expressed primarily in the doctrine of divine simplicity. Even those predicates whose ratio involves no mixture of imperfection can be denied from God insofar as the modus significandi of these perfections is different in God and the creature; what in finite entities is an attribute or property of the substance, in God is fully identified with the very divine being (ST I q.13 a.3 and a.5).
Gregory Rocca distinguishes three types of negation in Aquinas’ theology:Footnote 32 the simple qualitative negation, by which it is totally and absolutely denied that a certain quality can be applied to God (e.g., ‘God is immaterial’), the objective modal negation, by which it is affirmed that God possesses a perfection but denied that it is present in Him in the way it occurs in creatures (in this sense, any predicate can be denied of God regarding the modus significandi), and the subjective modal negation, by which certain ways in which human beings inevitably understand and think divine attributes, given the very nature of our language and conceptual resources, must be denied (this sense, closely linked with the previous one, also allows the denial of any predicate of God, especially considering the divine simplicity). It is by appealing to the latter two types of negations that Aquinas tends to read Pseudo-Dionysius’ most provocative assertions. Also, it is to highlight this sense in which all predicates can be denied of God that, in some contexts, Aquinas gives priority to negatio in his exposition of the triplex via.
II.D. Via Eminentiae and Causal Resemblance
For contemporary readers, the most problematic step in this account of the cause from its effects will undoubtedly be the via eminentiae. This stage plays a crucial role in the theology of Aquinas, since eminentia allows us to substantially affirm some positive names of God.
In ST I q.13 a.2, St. Thomas criticizes the positions of Maimonides and Avicenna,Footnote 33 who allegedly defended a very agnostic negative theology, according to which all the names applied God in an affirmative way are used to express either an indirect denial or else some sort of relationship between God and creatures. Against this proposal, Aquinas poses quite forceful objections and defends the incorporation of a third kind of divine predication, precisely the via eminentiae. This happens mainly because the first two forms of attribution do not allow us to predicate real properties of God, but only negative and extrinsic ones. Thus, the possibility of attributing names substantially to God is expressly associated by Aquinas with the thesis according to which the effects must virtually pre-exist in their cause in a more perfect way.
The via eminentiae depends on what could be called ‘the principle of causal similitude’, according to which causal relations demand that the perfections communicated to the effects pre-exist super-eminently in their cause. This principle will be probably regarded very contentious by a non-Thomist contemporary reader, and it is worth asking whether it can plausibly be applied to any relation of causality or only to some peculiar forms (those Aquinas describes as participatio). Is this the scholastic thesis completely outdated by modern science? Or is it actually the case that whenever describing a cause based on its effects, we cannot assume complete heterogeneousness if we want our explanation to be intelligible? In short, we are facing a subject that deserves a much more detailed study than the present pages allow, and one that could become the true Achilles’ heel of Aquinas’ natural theology.Footnote 34
III. The Hermeneutic Function of the Ways and their Demonstrative Power
The true force of Aquinas’ ways as arguments for theism could only be appreciated once they have been used to achieve a metaphysically elaborated concept of God and his relation to nature. Rushing to assess whether or not the immediate result of the ways coincides with a previous purely religious-based concept of ‘God’ instead of letting natural theology develop its own conclusions may block this rational itinerary and prevent us from ever benefiting from the exercise. Having this in mind we can now return to (3) –gap problem.
Recent literature sometimes chooses to relativize the idea that the ways pretend to be rational demonstrations of the existence of God. Lubor Velecky says that the ways do not claim to be truly ‘proofs of the existence of God’, but only ‘proofs that God exists’.Footnote 35 His argument is based on the distinction between ‘Dei esse’ and ‘Deum esse’ that Aquinas makes in ST I q.3 a.4 ad.2. Such distinction made sense for the purposes of the objection Aquinas was responding there, but it would be unfair to think that all of those who today say that the ways are demonstrations of the existence of God are implying that through them we can know the divine actus essendi. It is difficult for me to understand in what sense could any argument demonstrate the actus essendi of anything. Existential proofs are always proofs that certain things exist, not an intellectual grasp of the act of being of the things in question.
Another approach is represented by Pasquale Porro,Footnote 36 who claims that the use of elliptical expressions such as ‘et hoc omnes dicunt Deum’ (and this everyone calls God) should be seen as a deliberate gesture: Aquinas knows that the demonstration in question has not led to God in himself, but to a general cause of all things that we can, in a way, identify as ‘God’. This is partly true, but I disagree with the opinion of this same author, according to which the ‘philosophical God’ would be called ‘God’ in an extrinsic and provisional way at this stage of the argument.Footnote 37 I would rather say that this and no other is the primary meaning of the expression in question, and that this extrinsic nominal definition is the only sort of definitions we are ever going to have during the present life state. Considerations about the way in which the great monotheistic religions use the concept should not excessively condition our judgment on the demonstrative value of the arguments. Aquinas does not give us further justification for the nominal definition involved in the demonstration, because all what is needed here is a vague and general understanding on how the name ‘God’ is normally used in common language. Nominal definitions are not the result of a systematic scientific research, but a highly pragmatic and conventional way of indicating what we normally mean by a certain word. There are no requisites this implicit definition must fulfill for the argument to be successful, because Aquinas’ main concern at this stage is not with the common use of a given name (he will develop that concern much later, in q.13, once God's existence and entitative attributes have already been stablished). For natural theology, ‘God’ is simply the philosophical God, that to which the arguments that open the treatise conclude. Therefore, the only nominal definition that matters here is the definition provided by the argument's conclusion.Footnote 38
A separate matter is whether the way in which classical theism conceives of God is capable of rational justification. We could certainly insert the ways in a wider argumentative complex that pursues the specific demonstration of the truth of classical theism, we may even inspire this enterprise in the texts of Aquinas’ himself and be successful at it, but when doing that we will be going beyond natural theology as such. In any case, the project is not hopeless, because the nominal definition that results from the arguments for God's existence, once it has been further developed according to (5) –the hermeneutic program of triplex via, has an important similitude to the theistic image of God.
Adopting (2) –non-prescriptive approach, means that the nominal definition of ‘God’ to be used in the proofs will be provided by the demonstrations themselves. Twetten reconstructs, from various texts of Aquinas, three conditions a satisfactory nominal definition should meet in order to serve in an existential argument: It must be drawn from the effects, it supposes certain negation of or a relationship towards them, and it must be commensurate with the nature or essence of what we are demonstrating.Footnote 39 Certainly, the ‘definitions’ of God that Aquinas has at the end of his Five Ways do fulfill these conditions. They all express a causal relationship between God and creatures: God is the cause of entities that are mobile, ontologically dependent, contingent, share in perfection at different levels, and are ordered towards certain ends. In addition, this cause is described as a different reality, separate from and transcendent in relation to its effects: God is an ‘unmoved mover’, an ‘uncaused cause’, a ‘per se necessary being’, a ‘maximally perfect being’, and ‘an intelligent being guiding all things to their proper fulfillment’.
The result of the argument does indeed fulfill Twetten requirements, but I don't think that is due to an implicit set of rules governing the construction of nominal definitions to be used in an existential arguments. Triplex via is presented as a program for the further development of the notion at which the arguments arrive, not a touchstone for the arguments success. Still, once we have used triplex via to develop the notion, we can return to the background problem of ordinary language about God. When considering this further matter Aquinas will lay down his nominal definition (ST I q.13 a.8), suggesting that triplex via captures correctly what people normally mean when talking about ‘God’. It is also at this stage of the argument that someone could more fairly accuse him from rushing the conclusion by assuming too easily that such a description makes a correct indication of what the word commonly means. However, if Aquinas' suggested nominal definition is granted, it is obvious that all what has been said so far in the Summa provides rational justification for belief in ‘God’. This possibility of a retrospective apologetical assessment is the fundamental intuition behind (4) –total package defense.
But this does not mean that the existence of God is only proven by the end of the discussion of divine attributes, or that Aquinas’ ways fail in their objective if not supplemented with further argument. The Five Ways may indeed succeed in achieving precisely what their author intended.
Certainly, if The Five Ways were fundamentally supposed to apologetically establish the truth of classical theism, determining the meaning of this proposition in daily discourse would indeed be a prerequisite, and each argument should conclude with an additional step showing how the conclusion satisfies the nominal definition stipulated. But such pre-establishment of the meaning for the word ‘God’ is extremely difficult, since its everyday use is full of ambiguities. Shedding light on these is perhaps the main contribution of Aquinas’ philosophical exercise; stylizing the rational ways by which God can be reached using human reason is somehow the most profound purpose of the ways. Aquinas himself considered his arguments rigorous demonstrations, but they are not ‘demonstrations’ in the sense modern science understands this word. Aquinas tries to elaborate his theology according to Aristotelian standards for science, and the Aristotelian episteme is not so much about establishing the truth value for certain propositions, but rather, assuming these propositions are already known to be true, integrating them into a demonstrative framework that adequately exhibits their causal and explanatory relationships.Footnote 40 The main contribution introduced by scientific systematization is neither discovering new truths nor attaining greater warrant for them, but reaching greater intelligibility, i.e., a deeper intellectual penetration of the meaning, foundations, and implications of the truths involved.
Conclusion
When proving God's existence, Aquinas allows himself a ‘non-prescriptive’ approach—he simply takes for granted, or even stipulates, that the conclusion of his ways is what is to be referred by the word ‘God’. Afterwards, the process of giving an account of God based on His explanatory function towards the world is developed according to the triplex via: God is the cause of all things (via causalitatis) and, as such, must be different from them (via negationis), and all the perfections that He communicates to creatures must eminently pre-exist in Him (via eminentiae). The causal relationship between God and the world is the starting point for all reflection on Him, and the arguments to show that God exists contribute to its conceptual articulation. Eminence and denial follow from the understanding of the causation present in the ways and are intertwined in the specification of the divine attributes.
This structure gives Aquinas project of proving that God exists a primarily semantic and hermeneutic objective. Of course, this does not preclude the process from also having some apologetic efficacy, but in order to assess that dimension we cannot isolate the ways from the wider program within which they are inserted. Therefore, there is not such a thing as a ‘gap problem’ for natural theology as such, and the ways themselves will be successful or not independent from their usefulness in the justification of what contemporary literature commonly dubs ‘classical theism’. Still, the project of justifying religious belief in ‘God’ could benefit from the ways, and particularly from a development of the result of such arguments that follows the systematic program of triplex via. Aquinas' writings seems to resemble that approach, which is why the discussion of divine attributes occupies a considerably larger space than that of the existence of God. And yet this first question was by no means trivial—it constitutes the fundamental ground for the whole of our discourse on God. Perhaps it was no accident that Aquinas chose to name his arguments precisely viae—`paths.’
