The work of Thomas Aquinas, though somewhat insignificant in his own day, is arguably some of the most studied, discussed, and revered to emerge from the medieval period. As Plantinga, Thompson and Lundberg maintain, ‘of all the theologians, it is undoubtedly the shadow of Thomas Aquinas (c. 1225-74) that looms largest over the Latin theology of the Middle Ages.' Merely one capable theologian amongst many in the Middle ages, the Thomist works have since gathered copious esteem, valued as the perfect manifestation of reason used in defense of faith within a systematized theology. This dynamic between faith and reason is what underpins the entirety of Aquinas’ theology; absolute priority is afforded to faith, reason merely acting as a tool to expound the truths of faith graciously bestowed upon us through revelation. Theology is faith seeking understanding, but the tool of reason utilized to achieve such understanding should never be so arrogantly deployed so as to undermine the truths of faith. In this essay, I will aim to further examine Aquinas’ stance on the correct relationship between faith and reason and, subsequently, assess how this understanding is mapped onto the Thomist theology of the sacraments and, specifically, the Eucharist. Aquinas’ Eucharistic work is perhaps one of his most enduring contributions to theology; indeed, as Davies writes, ‘he is often thought of as the eucharistic theologian par excellence of the Catholic Church…' I will seek to sustain the line of argument that Aquinas’ Eucharistic theology acts as a microcosmic manifestation of his theological method; faith and tradition provide the theological truths which Aquinas subsequently expounds using reasoned argument- not to prove or give credence to his beliefs of faith- but merely to defend them and to understand them on a level beyond the mere acceptance and ascent to certain propositions.
Throughout his career, Aquinas, like most prominent academic theologians, was embroiled in the debate over the correct utilization of philosophy, specifically Aristotle, in the universities. It is due to his desire to reject the adoption of radical Aristotelianism that Aquinas offers a systematic account of the relationship between faith and reason, ultimately granting the latter the position of handmaid to the former. The term ‘handmaid’ has connotations of subordination, however, which seems contrary to Aquinas’ understanding of the two disciplines; as Sigmund writes, ‘for Aquinas…a belief that faith and reason were both valid and divinely legitimated sources of human knowledge meant that neither should be considered as dominating the other.' Both divinely inspired, it is impossible that the disciplines of reason and faith should contradict and, therefore, one cannot exist as subordinate to the other, merely equal and complimentary. As Aquinas writes For that with which the human reason is naturally endowed is clearly most true; so much so, that it is impossible for us to think of such truths as false. Nor is it permissible to believe as false that which we hold by faith, since this is confirmed in a way that is so clearly divine. 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. This being said, however, reason cannot, according to Aquinas, function alone in determining the highest theological truth. The highest truths about God can only ever be revealed by God himself and cannot be discerned through reason and deduction from nature; as Plantinga, Thompson and Lundberg write, ‘truths such as the triune nature of God or creation ex nihilo could be known only through faith’s dependence on grace…reason is capable of much, but it must be complemented by faith.' Niederbacher offers a neat formula for what Aquinas would consider propositions of faith or ‘credible’ propositions, ones which ‘belong to the object of faith that are believed on God’s authority' ‘A proposition p is a credible proposition if and only if i) p is true ii) p is revealed by God; iii) p is assented to because p is revealed by God; iv) p presents truths about God and created things insofar as they are necessary and sufficient for orienting the life of human beings toward their last end. ‘ These propositions can, evidently, be assented to because they are revealed, and not because we reason to them. However, the highest principles of faith, though unable to be demonstrated by human beings, can be defended using reasoned argument, ‘ thus, Aquinas claims, that one should be able to show that these principles of faith are not impossible, that they do not contradict what is self-evident or demonstrable, that defeaters can be defeated, that one can draw conclusions from the principles in a deductive way.' Some of the more basic theological truths, such as that of God’s existence, Aquinas does believe to be rationally demonstrable; when discussing our assent to the precepts of the Decalogue, for example, he does not make reference to divine revelation to explain our knowledge of the content of the natural law but argues that It is therefore evident that since the moral precepts are about matters which concern good morals; and since good morals are those which are in accord with reason; and since also every judgment of human reason must needs be derived in some way from natural reason; it follows, of necessity, that all the moral precepts belong to the law of nature Reason should not be fought against since, as Cross puts it, ‘God’s giving human beings reason is a necessary consequence of his creating human beings: being rational is part of what it is to be human.' It is, however, limited.
Aquinas’ understanding of sacramental theology in general is not something he reasons towards but something he inherits as a truth of faith from the Christian tradition. The sacraments are derived from Christ’s death on the cross since it is in the flesh that he offers, and humans receive, grace. From the pierced side of Christ, the blood and water, the Eucharist and baptism, flow; Aquinas writes that ‘on Romans 5:14: “After the similitude of the transgression of Adam,” etc., the gloss says: “From the side of Christ asleep on the Cross flowed the sacraments which brought salvation to the Church.” Consequently, it seems that the sacraments derive their power from Christ’s Passion.' Faith, for Aquinas, should have implications for the way in which Christians behave; it is through partaking in the sacraments that Christians live a life directed towards God and a life lived in Christ. They serve the dual function of offering sanctification and simultaneously acting as a form of worship. It does seem that Aquinas’ sacramental theology is expounded through the use of reason, however. For example, he emphasizes the dual nature of sacraments as both signs and causes of grace; as Torrell and Guevin observe, ‘ Thomas’s definition of sacrament…brings together both meaning and efficacy in one formula: “the sign of a sacred reality that is acting to sanctify man.”‘ Sacraments are signs which represent the sanctification which they bring about, ‘symbols which make real what they symbolize.' Aquinas is also able to assert that sacraments are causes of grace insofar as the materials utilized are those which God uses to provide grace, they are ‘instrumental causes.' Aquinas draws a distinction between this kind of ‘instrumental cause’ and what he calls ‘principal causes’ of grace. He argues that the latter ‘produces its effect in virtue of its form’; God produces grace this way as its principal cause. Sacraments, however, serve as instrumental causes of grace in that they produce grace ‘solely in virtue of the impetus imparted to it by the principal agent…it is by divine institution that they are conferred upon us for the precise purpose of causing grace in and through them.' The instrumental parts of the sacraments are many; as Jordan notes, ‘the same instrumental power is found in the very different elements of a sacrament- in its verbal formulae, its prescribed actions, its material. Finally, the instrumental efficacy of the sacraments depends on the efficacy of the humanity of Christ, itself an instrument of His divinity.'
Aquinas also reasons that the sacraments are necessary for human beings; his reasons are threefold. Firstly, he reasons from the idea that since ‘it is characteristic of divine providence that it provides for each being in a manner corresponding to its own particular way of functioning' to the idea that people are aided by the sacraments in a way which is appropriate to the human way of coming to knowledge- through physical things. His related second reason argues that humans, ‘if they were to be confronted with spiritual realities pure and unalloyed their minds, absorbed as they are in physical things, would be incapable of accepting them.' Finally, he argues that sacraments make worship easier for us since they involve the continuation of our relationship with the physical; as Davies puts it, ‘in Aquinas’ view, sacraments are fun.'
Within his sacramental theology, as a whole, the dynamic between reason and faith which Aquinas has set up becomes manifest; he accepts the necessity and value of sacraments in faith, and accepts the method of administration of the sacraments from tradition; he does, however, use reason to explain the mechanism behind the sacraments and to examine the intricacies of sacramental theology. It is in his treatment of the Eucharist, however, that we can see most clearly the dialectic between reason and faith play out.
The Eucharist is, as Davies notes, ‘the crowning sacrament' for Aquinas (hence his recommendation of daily communion); it is the sacrament towards which all of the others are directed, the culmination of the Christian life, the believer brought into unity with Christ, ‘all the benefits involved in the Incarnation…carry over into the Eucharist.' Through its receivers sharing in the passion, the Eucharist is also a mechanism through which sins are forgiven. In order for these things to be the case, Christ must be truly present in the sacramental bread; Aquinas is emphatic on this point- ‘Christ is sacramentally contained in the Eucharist' , ‘the real body of Christ and his blood are in this sacrament', ‘the reality of this sacrament demands that the very body of Christ exist in it.' The presence of Christ is present in the most direct and imminent sense, hence the import of the Eucharist; as Walsh writes, ‘from the point of view of the one who receives it, the Eucharist gives a bonding with Christ himself, in the full reality of his being, whereas the other sacraments give a transient, functional contact with Christ. The Christ received in the Eucharist is Christ in the fullness of his priesthood and the fullness of his glory.' Aquinas’ assertion of the real presence of Christ, however, is not something which we can argue is derived from reason or philosophical argument, but only through faith. As Davies notes, ‘belief in the literal or non-symbolic eucharistic presence of Christ is not, for him, something grounded on what we might recognize as proof or demonstration. As he sees it, it is something implied by Christian faith.' Indeed, Aquinas asserts that ‘the presence of Christ’s true body and blood in this sacrament cannot be detected by sense, nor understanding, but by faith alone, which rests upon Divine authority.' The real presence of Christ is implicit in scripture through the correct (i.e. literal, non-symbolic) interpretation of the statement ‘this is my body’. For Aquinas, we must take these words as they are written since they are the words of Christ and must, therefore, be true.
Though Christ’s presence in the bread is a belief fostered through faith, Aquinas’ famous doctrine of transubstantiation represents his belief in the ability of reason to expound principles of faith. He affirms transubstantiation as the absolute mechanism through which Christ comes to be present in the sacramental bread and wine; ‘take away the transubstantiation’, writes Kenny, ‘…and you take away the presence.' Aquinas explains transubstantiation as follows: the whole substance of the bread is changed into the whole substance of Christ’s body, and the whole substance of the wine into the whole substance of Christ’s blood. Hence this is not a formal, but a substantial conversion; nor is it a kind of natural movement: but, with a name of its own, it can be called “transubstantiation.” Aquinas adopts the Aristotelian language of substance and accidents in order to explain how the body of Christ is consumed at the Eucharist yet the taste, smell and feel of the bread remain. Though in traditional philosophy, accidents are usually spoken of in terms of being bound to a subject, Aquinas argues that accidents have natures suited to existing in a substance' but, in the Eucharist, the accidents of bread and wine are somehow maintained independent of their respective substances. Cross maintains that Aquinas uses two somewhat inconsistent strategies to defend this view, firstly arguing that the separated accidents ‘acquired individual esse in the substance of the bread and wine' but when separated from this substance, are maintained by God. Kenny offers the useful analogy of the smell of onion lingering after the onion has gone or the imprint of a boot in snow remaining once someone has walked on. In a similar way, the accidents of the bread are real and linger on but, substantially, Christ is present and not bread. The second strategy which Cross identifies is that ‘while the substance of the bread and wine remained, accidents of this kind did not have esse…rather their substance had esse through them…after the consecration, the accidents that remain have esse.'
Aquinas’ doctrine of Transubstantiation is reasoned towards through a series of arguments; the doctrine emerges out of his reasoning from propositions he holds to be true and making deductions from these truths. For example, if it is Christ’s body that is present in the Eucharist (a true statement by faith), then it must be the case that the bread and wine changed into Christ’s body; something can only become something else by being created there (which Christ is not), moving there from another place (an impossible idea, since this would involve Christ moving from his place at the right side of God), or by changing into that thing. He also reasons towards the rejection of the symbolic understanding of the Eucharist by arguing that it would render Christ a liar when stating that ‘this is my body.’ It would be impossible for Christ to be untruthful. In addition, Aquinas notes that if the bread and wine remained throughout the sacrament, Christian believers would be guilty of idolatry when taking the sacrament, since they would be revering as divine something which is not. In all of these arguments we can see the dialogue between faith and reason; true statements of faith give rise to reasoned arguments which defend them. These reasoned arguments, in turn, lead to theological deductions. In conclusion, Aquinas’ Eucharistic theology acts as the perfect microcosm of his method; his attitude to the relationship between faith and reason is mapped onto his Eucharistic theology and, through understanding the steps he takes to arrive at his conclusions, we are able to see the dynamic between faith and reason at play; faith provides the theological truths upon which Aquinas builds, through reason, his sacramental theology. Through defending these undeniable truths of faith, other probable truths become clear, such as the doctrine of Transubstantiation. Aquinas expounds the truths of faith- not to prove or validate his beliefs- but merely to defend them, and to understand them on a level beyond mere acceptance and assent.
 Plantinga, R. J., Thompson, T. R. and Lundberg, M. D., An Introduction to Christian Theology (Cambridge: Cambridge University Press, 2010), p468
 Davies, B., The Thought of Thomas Aquinas (Oxford: Clarendon Press, 1992), Ch. 17, p.17
 Kretzmann, N. and Stump, E., The Cambridge Companion to Aquinas (Cambridge: Cambridge University Press, 1993)
 Aquinas, T., Summa Contra Gentiles I, by A. C. Pegis (Notre Dame, IN: University of Notre Dame Press, 1975) 7.1.
 Plantinga, R. J., Thompson, T. R. and Lundberg, M. D., An Introduction to Christian Theology (Cambridge: Cambridge University Press, 2010), p470
 Bruno Niederbacher, The Relation of Reason to Faith. Davies, B. and Stump, E., eds, Oxford Handbook on Aquinas (New York; Oxford: Oxford University Press 2012), p.2.
 ibid, p. 5
 Summa theologiae I-II, q. 100, a. 1 c
 *Cross, R., The Medieval Christian Philosophers: An Introduction (London: I. B. Tauris, 2014), p.122
 Summa theologiae 3.62.5
 Torrell, J.-P., Aquinas’s Summa: Background, Structure and Reception (Washington, D.C.: Catholic University of America Press, 2005), p. 58
 Davies, B., The Thought of Thomas Aquinas (Oxford: Clarendon Press, 1992), Ch. 17, p.8
 Summa theologiae 3. 62. 1
 Kretzmann, N. and Stump, E., The Cambridge Companion to Aquinas (Cambridge: Cambridge University Press, 1993), p219
 Summa Theologiae, 3. 61.1
 Davies, B., The Thought of Thomas Aquinas (Oxford: Clarendon Press, 1992), Ch. 17, p.15
 ibid, p.17.
 ibid, p.19.
 Summa Theologiae, 3.73. 5.
 ibid. 3. 75. 1
 ibid, 3.75.2
 Van Nieuwenhove, R. and Wawrykow, J., eds, The Theology of Thomas Aquinas (Notre Dame, IN: University of Notre Dame Press, 2005), p.360
 Davies, B., The Thought of Thomas Aquinas (Oxford: Clarendon Press, 1992), Ch. 17, p.22
 Summa Theologiae, 3. 75.1
 Kenny, A., Reason and Religion: Essays in Philosophical Theology (Oxford: Basil Blackwell, 1987), p.18
 Summa Theologiae, 3.75.4
 Davies, B., The Thought of Thomas Aquinas (Oxford: Clarendon Press, 1992), Ch. 17, p.31
 Summa Theologiae III, 77.1.3. Cited in Cross, R., The Medieval Christian Philosophers: An Introduction (London: I. B. Tauris, 2014), 114
 Summa Theologiae III, 77.1.4. Cited in Cross, R., The Medieval Christian Philosophers: An Introduction (London: I. B. Tauris, 2014), 114