1) There are a number of helpful topics by which one might examine some of the differences and similarities across the centuries from the Medieval period up through the Reformation, and each allows a set of concerns to come into focus. The related questions of the nature of grace and whether a person might merit salvation is one such helpful pair of topics. These questions, conjoined from the Middle Ages through the beginning of the Reformation, begin at a point where they are very much tied up with ontological questions about the relationship between beings and God, and about the character of knowledge, in general, and the nature of theological knowledge, in particular. Do beings naturally participate in God to some degree (i.e., in a manner according to the nature of a being), or are they wholly separate, radically contingent and entirely superfluous ephemera of the divine will, thoroughly alien in their being to divinity, without a native point of contact? Is knowledge –even secular knowledge– a participation in divine knowledge, or is it a navigation of singularly unique particulars through signs? Is grace participation in God, likeness to God, favor from God, divine acception, or else some or even all of these? Is this grace something which people are able to know they are partaking of? The Nominalists’ and Reformers’ answers to these questions illumine some of the crucial elements that come to characterize the Modern period, our secular cultural condition. We will begin with Thomas Aquinas (1225–1274), briefly noting the Ockhamist/Nominalist tradition which follows shortly after him, then we will move through these questions in Martin Luther (1483–1546).
2) The story beginning with Aquinas demands a brief prefatory note regarding Peter Lombard (ca.1096–1164). Lombard’s major work, the Sentences, consists of a series of “distinctions” which work their way sequentially through what are, for us, the familiar dogmatic loci of Christian theology – the Trinity, &c. In the course of these distinctions, Lombard addresses the apparent conflicts among textual authorities and traditional interpretive options of the same. In fact, the resolution to the tensions within the Christian tradition that the Sentences attempts to provide is itself one of several interpretive options. These fissures, which the Sentences suppresses by attempting to provide a resolution, prefigure the divisions which eventually appear centuries later in the rifts between various confessional parties, Protestant and Roman Catholic. Lombard, in discussing the sending of the Holy Spirit into the hearts of the faithful, takes the following to be a premise: “[…] the Holy Spirit is the love of the Father and the Son by which they love each other and us. It must be added to this that the very same Holy Spirit is the love or charity by which we love God and neighbor. When this charity is in us, so that it makes us love God and neighbor, then the Holy Spirit is said to be sent or given to us; and whoever loves the very love by which he loves his neighbor, in that very thing loves God because that very love is God, that is, the Holy Spirit.” This makes our love divine, a real Gift of God, a participation in divine life, and the Third Person of the Godhead in truth. What it is not is our own love, our own loving. Steven Ozment summarizes Lombard on this point: “Man is saved by an uncreated, not a created habit, by uncreated, not created, love, by the Holy Spirit within, not by an acquired talent he can call his very own.” After noting that Luther would later agree with Lombard on this issue, Ozment cites Thomas Aquinas’ reply to Lombard on the matter. Lombard, writes Thomas, “did not mean that the Holy Spirit was identified with our movement of love, but that charity […] was not elicited from a habit which was really our own”, making us “passive”, which is a “problem”, “for our loving is very much our own.” This disagreement prefigures the later Lutheran-Roman Catholic fault lines on this matter.
3) Aquinas understood God and the world as organically connected through a chain of being which flowed from God, as the limitless source of pure, actualized being, to beings; it is in this context that his understanding of knowledge, grace, and merit are set. All things come from God, the good, and are oriented to him in their root and principle, each being an expression of his goodness. Unsurprisingly, even natural knowledge was a participation in God, with the result that “[f]or Aquinas, human experience was a positive basis for understanding religious relations, because God and man shared a common reality” through human participation in the divine root (God is the common reality, not some third term). Yet if they share a common reality, the question arises of how, precisely, they relate. Thus, the question Ozment asks to focus discussion of the Scholastics: “how [can] grace […] be present in man’s soul[?] How can something divine be within human nature?”
Aquinas’ answer is set within a larger canvas, and this canvas is rich. Human beings, and beings in general, come from God, and return to God, from a divine motion of love. If only like can know like, then knowledge of God is available to everything, for “God is the First Mover, simply, it is by His motion that everything seeks to be likened to God in its own way.” [109.6 (these numbers are sections from the “First Part of the Second Part” of Aquinas’ Summa Theologica)] Beings are not fully autonomous things, nor are they totally unlike God, but, as a result of their divine origin, are theophanies: as God is the perfect fullness of being, and the consummate good, and all things are beings, manifestations of the good, for God to withdraw from a being would be for that being to vanish: “if [the good] had been withdrawn, even [a person’s] nature would have fallen back into nothingness.” [109.8] (This position is basic to all Platonic traditions, which see that to be as equivalent to being intelligible, and so equivalent with a relative degree of unity, symmetry, harmony — i.e., goodness. This does not mean that the mode of a thing is good.) Yet God wills all things in the simple act of willing himself: all things are contingent manifestations of God, and exist for the end of the display of the perfect good from which all come and to which all are appointed. “God seeks from our goods not profit, but glory, i.e. the manifestation of His goodness” [114.1]. This is a cosmic movement of love: “to love God above all things is natural to man and to every nature, not only rational but irrational, and even to inanimate nature, according to the manner of love which can belong to each creature.” [109.3] Indeed, God’s moving of creatures is neither violence nor an external imposition, but a natural and appropriate thing, for he “moves everything in its own manner, just as we see that in natural things, what is heavy and what is light are moved differently, on account of their diverse natures.” [113.3] God moves all things as the good: “the common good of the whole universe […] is God” [109.3], who is “the eternal good” [110.1], “the […] common good” [111.5], and “the Highest Good” [112.4]. While many things are good for human beings, God alone is the simple good of persons, being himself the simple and the good [114.10]. While all things will, in every act of willing, some sort of worldly good, they do so in a manner proportionate to their nature. Grace is different, because it does not move one to a worldly good, but to God, the eternal good.
In Aquinas, even ordinary knowledge participates in God, underscoring that God is participated in always, at some level, even in ordinary knowing and reasoning: the First Mover moves everything, even the human faculties involved in secular knowledge. Aquinas teaches that the mind is less corrupt than the will and the flesh, and that the mind is the first to be corrected in the order of salvation (the will follows the mind/intellect). “[H]uman nature is more corrupt by sin in regard to the desire for good, than in regard to the knowledge of truth.” [109.2] The mind’s proper object is, effectively, God, the good, as “the intellect […] precedes the will” [113.4], and the “good […] is the object of the will” [113.4] – for will follows intellect, each thing is organically connected to God, referred to him natively as to the end proper to it, as an arrow to the bullseye on the target, and necessary to it for its own flourishing. The contemporary scholar Steven Ozment notes that this means that we sin when we move to a temporal good, rather than our eternal good, as though a natural movement towards goodness gets snagged on some lesser object. Our dulled mind leads to a disordered appetite/will, which seeks not God as the common good, but our private good, making us an egotistical splinter. Not surprisingly, if the natural good of each and all things terminates in God, harmony between creatures and between creatures and their mutual divine root follows naturally from one following the course of one’s nature: “to sin is nothing else than to stray from what is according to our nature […].” [109.8] For Aquinas, knowledge is certain, and requires the limits, boundaries, the principles of things; grace is divine, and so its principle is limitless and the end of its movement (God) cannot be known (knowledge involves limits; God has no limit, no boundary). Yet faith is certain. The epistemological assumption behind this is that “only like [can] know like”, something divine must be in us, something that extends to knowledge of God beyond the limits of our nature. This seed of grace by which we know, this gift of the Spirit, is called a “pledge” [114.3]. Unlike the sign-based understanding of a “pledge” that would come later, Aquinas sees signs as merely conjectural, and so this “pledge” is not a sign — that is, the knowledge had from this “pledge” is not sign-based.
Merit concerns reward, and reward is appropriate to a relationship which is just, which has the form of justice. Justice, however, requires equality, or else it is not simple; and yet reward can be relative, and not simple, when there is a relationship of inequality. There is the greatest inequality between the unlimited, infinite (God) and the limited, finite (beings). Thus, between God and beings, there is only a proportionate equality “inasmuch as both operate after their own manner.” [114.1] As grace is a seed, and full eschatological participation in God the tree [114.3], so merit should be considered with regard to its incipient divine form, its final divine goal, and our (hopefully) growing human participation (interruptions are possible) in the goal contained in this initial pledge/seed.
With regard to our acts of charity, there is no justice or equality between our acts and the reward at the end of faith: our acts of charity following from this seed, this pledge, are always human acts, and so they do not have “condign” or full merit. (They do have relative or “congruous” merit, the human being working proportionately after his or her own manner, “if a man does what he can” [114.3], even though “the first act must flow from grace” and so “cannot be meritorious of the first grace” [114.5], for in this sense “all merit is repugnant to grace” [114.5] when the gift itself is considered. The initial bestowal is gratuitous; no creaturely act can merit the bestowal of grace. The rational creature, however, once moved by the gift of grace from the First Mover, moves according to the manner of a rational creature, and this movement involves what Aquinas calls ‘free will’: a free movement involves some kind of congruous merit, as these free acts participate in grace in their grace-caused faith and grace-moved charity, and aim at a supernatural end, so that there is some kind of relationship or proportion between them, however immeasurable.)
With regard to the divine pledge of the Spirit and grace, however, there is condignity, because the divine end is already contained in the divine seed, so that there is equality and justice; as only God can be equal with God, so that it is by God’s own work in them that they attain to salvation, human beings can have condign merit. Thus, “our merit is a subsequent cause” of our “reaching everlasting life”, “the first” being “God’s mercy.” [114.3]
Humanity, in Aquinas, has an end that is proper to its nature, though this nature is limited like all natures, its end less than perfect charity; the end of human nature is an articulation of God, the good, but is not perfect blessedness and a share in divine joy. The principles of the actions of all things are from God, but the principle of everlasting life is beyond the principles of the activity of human life and being. Thus salvation requires that humanity be elevated above the limit and end proper to its nature, and oriented to God as the proper end of all things; this is grace. Grace, in Aquinas, formally acts upon humanity to expand the powers of its motion to an end above the ends of its nature.
Because the human being has both intellect and will, a supernatural infusion of grace involves the infused virtues of faith (relative to the intellect) and charity (relative to the will) – and this means it involves expanding the range of freedom’s powers to draw it to God in the movement of faith and love. Freedom does move by its own, now expanded power, but, it could not have thought about even seeking this supernatural end without first being moved to it by God preveniently, for all beings are limited, and the principles of their movement take them to ends that are themselves limited – but grace is an unlimited principle of movement into an unlimited good, God. Only God can move natures to such an unlimited, infinite, supernatural end, for God is the First Mover, and the origin and end of all things as Actus Purus and Perfect Good.
The origin of grace lies with God, who does not, in fact, move all people to salvation. God can move anyone to blessedness, and yet does not do this for all. Some are given grace, but perhaps not all are given perseverance in grace, although Aquinas does cite Augustine, who wrote that “grace is related to the will or to the free will “as a rider to his horse” [110.4, Obj.1], which would seem to imply a kind of inevitable perseverance through grace indwelling the will, which itself is “a power of the soul”. This doesn’t make God a puppeteer, or any other such metaphor of manipulation: God is simple, and when speaking of his intellect and will, as when speaking of his choices, there is also simplicity: the content of God’s knowledge is simple, as it is all-containing self-knowledge, and the object of his will is simple, as his gratuitous self-willing self-multiplication, of sort. Creatures are each and all by-products of this simple, unitary, eternal act of divine self-willing self-multiplication, and they are naturally oriented to God as contingent means to this, their necessary end. God’s will is one act. This is not a set of discrete choices God makes –which would falsely imply that the failure of some to enter into eternal life stems from a set of negative choices which God makes– but the fallout of a single, simple, infinite willing or act.
As a final note, the philosophy-of-being elements in Aquinas do not seem to sit with total comfort beside the Christological and sacramental elements. Although Aquinas never denies that grace can come by another way than the sacramental one, he does not necessarily relate the sacramental means of grace to God as the end of creatures and creation except by way of the ordinances of the divine will. So in [112.1], Christ’s humanity is “an instrument” of his Godhead, and does “cause grace” by the divinity “joined” to it, as though extrinsically. Further, “the sacraments of the New Law” cause grace “instrumentally”. There is here, incipiently, the later Medieval distinction between God’s absolute will and freedom, and his contingent will and the actual things and means he has instituted for salvation (which becomes cardinal for the Magisterial Protestant theological positions). The idea of natural symbols would seem to violate freedom, as though they imposed some sort of necessity on God. In Aquinas, God’s freedom does not appear to link up comfortably with his teaching of God’s will as having himself as its own object as the good. The divine freedom above and behind the signs, which gives them and opens up a universe of radical contingency, unlike a realist world of the analogy of being and the Neoplatonist cascade of natural names and symbols. Further prefiguring later developments is what he writes in [113.3], where a right intentionality is necessary for the reception of the sacraments.
4) Contextually, Aquinas’ understanding of grace and participation were set against the backdrop of an ecclesiastical institution which had successfully acquired a great deal of worldly power and possessions. The city, the state, the king – these were not the (super)natural telos of human life; God was, and the institution of the Church in the West at the time understood itself to be organically connected to, and ontologically descended from, the God in whom all organically participated, to some degree. The Church’s worldly power, and her spiritual power, were both able to map themselves onto, and found themselves upon, Aquinas’ model of participation in God, as this made them the fullness of authority, and anything but conventional. Luther would later criticize the “three walls” which the papacy had built around itself, accusing it of attempting to be alone the office descended from God, and having the authority to offer the final and binding interpretation of the biblical text, which was thus unable to be used as a set of divine signs for a massive project of revision, by which signs even the papacy might be criticized. The emphasis on signs and freedom also leads to an increasing emphasis on signs as mediating between free agents, signs as contracts of sorts, different from oaths of fealty, and much more in line with the budding mercantile economy. (Luther rejects that he and Erasmus are dealing with such mercantile conventions at the outset of his reply to Erasmus.) So justice for Aquinas is equal exchange, and though this grace is not for sale, it may be that, in the minds of Aquinas’ contemporaries, the likeness involved in the analogy of being is not totally separated from the likeness involved in the just weights and measures used in money-based transactions. (Money would seem to be rather unlike any given thing measured by it, and so likened to any given thing arbitrarily, in a way that exceeds the relative organic likenesses and mutual measurements involved in bartering.)
 Peter Lombard, The Sentences, Book 1: The Mystery of the Trinity, transl. Giulio Silano (Toronto: PIMS, 2007), 88.
 “For Aquinas, God, man, and the world were connected to one another not by verbal or artificial relations, but by the structure of reality itself. They related to one another like tendons to bones and muscles […] the relationship was organic […].” Ozment, Age of Reform, 54.
 [109.1] The “act of the intellect or of any created being whatsoever depends upon God in two ways: first, inasmuch s it is from Him that it has the form whereby it acts; secondly, inasmuch as it is moved by Him to act.” Further, to know things, mankind “does not need a new light added to his natural light, in order to know the truth in all things, but only in some that surpass his natural knowledge.” “Every truth by whomsoever spoken is from the Holy Ghost as bestowing the natural light, and moving us to understand and speak the truth, but not as dwelling in us by sanctifying grace […]. […] The material sun sheds its light outside us; but the intelligible Sun, Who is God, shines within us. Hence the natural light bestowed upon the soul is God’s enlightenment […].”
 [109.8] “man needs grace to heal his nature […] in the present life this healing is wrought in the mind – the carnal appetite being not yet restored. […] in this state man can abstain from all mortal sin, which take sits stand in his reason […]” [109.9] “although healed by grace as to the mind, yet it remains corrupted and poisoned in the flesh, whereby it serves “the law of sin”” [109.10] the restoration by Christ’s grace, although it is already begun in the mind, is not yet completed in the flesh, as it will be in heaven […].”[113.1] God “mov[es] and excit[es] our mid[s] to give up sin”, which movement causes the remission of sins. [113.4] “for the justification of the ungodly a movement of the mind is required, by which it is turned to God.”
 [113.1] “sin […] implies the disorder of a mind not subject to God”. “Faith and charity imply a special directing of the human mind to God by the intellect and will […].”
 [113.5] “the human mind […] by a movement of its free-will […]”
 [109.3] “in the state of corrupt nature man falls short of [seeking the common good] in the appetite of his rational will, which, unless it is cured by God’s grace, follows its private good […].” [109.7] The corruption of natural good in human beings means that “man’s will [is] not […] subject to God’s”, that is, to the good. [113.2] As a splinter, we are cut off from the good, from God, and are not at peace with our source and end: “an offense is remitted to anyone, only when the soul of the offender is at peace with the offended. Hence sin is remitted to us, when God is at peace with us […].””
 [112.5] “certitude about a thing can only be had when we may judge of it by its proper principle. […] no one can know he has the knowledge of a conclusion if he does not know its principle. But the principle of grace and its object is God, Who by reason of His very excellence is unknown to us […] hence His presence in us and His absence cannot be known with certainty.”
 [112.5] “It is an essential condition of knowledge that a man should have certitude of the objects of knowledge; and again, it is an essential condition of faith that a man should be certain of the things of faith”, for “certitude belongs to the perfection of the intellect” and “whoever has knowledge or faith is certain that he has them”.
 [109.1] “Higher intelligible things of the human intellect cannot know, unless it be perfected by a stronger light, [faith as the light of grace], inasmuch as it is added to nature.” [112.5]; [114.3] The principle of this is the grace of the Holy Spirit, which dwells in the human being.
 [109.3] There is a natural knowledge of God, though: “nature cannot rise above itself”, yet it “can “be drawn to” things “above itself, for it is clear that our intellect by its natural knowledge can know things above itself, as is shown in our natural knowledge of God.” In this sense, God is loved above everything by the human being, but not in a perfect way corresponding to eternal blessedness.
 [112.5] “[…] things are known conjecturally by signs; and thus anyone may know he has grace” by “delighting in God”, “despising worldly things”, and “inasmuch as” one is “not conscious of any mortal sin.” Then there is “the hidden manna”, and “whoever receives it knows, by experiencing a certain sweetness […].”
 [114.1] “God is [not] made our debtor simply, but His own, inasmuch as it is right that His will should be carried out.”
 [114.1] “man obtains from God, as a reward of his operation, what God gave him the power of operation for”.
 [109.2] “In the state of integrity”, the human being can “wish and do the good proportionate to his nature, such as the good of acquired virtue, but not surpassing good, as the good of infused virtue. […] [I]n the state of perfect nature man needs a gratuitous strength superadded to his natural strength […] in order to do and wish supernatural good”.
 [114.2] “no act of anything whatsoever is divinely ordained to anything exceeding the proportion of the powers which are the principles of its act; for it is a law of divine providence that nothing shall act beyond its powers.”
 [109.5] “without grace man cannot merit everlasting life; yet he can perform works conducing to a good which is natural to man, as “to toil in the fields, to drink, to eat, or to have friends,” and the like […].”
 [109.3] “nature loves God above all things inasmuch as He is the beginning and the end of natural good; whereas charity loves Him as He is the object of beatitude and inasmuch as man has a spiritual fellowship with God.”
 [109.9] “no created thing can put forth any act, unless by virtue of the Divine motion.”
 [109.7] “without exterior help [human nature] cannot be restored to what surpasses its measure.”
 [109.5] “no act exceeds the proportion of its active principle […] nothing can by its operation bring about an effect which exceeds its active force […] everlasting life is an end exceeding the proportion of human nature […]. Hence man, by his natural endowments, cannot produce meritorious works proportionate to everlasting life; and for this a higher force is needed, viz. the force of grace.”
 [110.2] “Grace, as a quality, is said to act upon the soul […] after the manner of a formal cause, as whiteness makes a thing white, and justice, just.”
 [110.3] “the virtue of a thing has reference to some pre-existing nature” and “everything is disposed with reference to what befits its nature.” By the virtues, “a man is fittingly disposed with reference to the nature whereby he is a man; whereas infused virtues dispose man in a higher manner and towards a higher end, and consequently in relation to some higher nature, i.e. in relation to a participation of the Divine Nature […].” [114.2] “everlasting life is a good exceeding the proportion of created nature; since it exceeds its knowledge and desire […]. And hence it is that no created nature is a sufficient principle of an act meritorious of eternal life, unless there is added a supernatural gift, which we call grace.” [114.5] Grace “exceeds the proportion of nature” because it is of a divine principle. [114.10] “life everlasting is simply the reward of the works of justice in relation to the Divine motion”
 [110.2] “the gratuitous effect in man is not a quality, but a movement of the soul […].”
 [113.3] “in him who has the use of reason, God’s motion to justice does not take place without a movement of the free will; […] at the same time He moves the free-will to accept the gift of grace […].”
 [111.2] God’s movement of the mind into a grace-filled movement of its own is still “not attributed to the thing moved but to the mover.” “God moves the human mind to this act”, almost as though we were wind-up toys, except that the mind has its own principles of movement; there is no coercion here. God does not heal us without our consent, but even “this movement is not the cause of grace, but the effect […]”
 [109.2] “[…] man’s free-will is moved by an extrinsic principle, which is above the human mind, to wit by God”.
 [112.2] “every preparation in man must be by the help of God moving the soul to good. And thus even the good movement of the free-will, whereby anyone is prepared for receiving the gift of grace is an act of the free-will moved by God.”
 [111.3] The soul is healed before good is desired.
 [110.2] “Now He so provides for natural creatures, that not merely does He move them to their natural acts, but He bestows upon them certain forms and powers, which are the principles of acts, in order that they may of themselves be inclined to these movements, and thus the movements whereby they are moved by God become natural and easy to creatures […].”
 [113.6] “in the movement whereby one thing is moved by another, three things are required: first, the motion of the over; secondly, the movement of the moved; thirdly, the consummation of the movement, or the attainment of the end. On the part of the Divine motion, there is the infusion of grace; on the part of the free-will which is moved, there are two movements” – away-from and towards, departing sin, moving to God.
 [112.1] “Nothing can act beyond its species […] the gift of grace surpasses every capability of created nature, since it is nothing short of a partaking of the Divine Nature, which exceeds every other nature. […] it is as necessary that God alone should deify, bestowing a partaking of the Divine Nature by a participated likeness, as it is impossible that anything save ire should enkindle.”
 [112.3] “the gift of grace exceeds every preparation of human power.”
 [109.6] God “directs righteous men to Himself as to a special end […]. And that they are “turned” to God can only spring from God’s having “turned” them.” [109.6] “Man’s turning to God is by free-will; and thus man is bidden to turn himself to God. But free-will can only be turned to God, when God turns it” [109.7] “man’s will can only be subject to God when God draws man’s will to himself […].” [112.2] “a man cannot prepare himself for grace unless God prevent and move him to good” [113.4] “God moves man’s soul by turning it to Himself”
[113.7] “The entire justification of the ungodly consists as to its origin in the infusion of grace.” “God, in order to infuse grace into the soul, needs no disposition, save what He Himself has made. […] since the Divine power is infinite, it can suddenly dispose any matter whatsoever to its form; and much more man’s free-will […].”
 [109.10] “to many grace is given to whom perseverance in grace is not given.” It is not clear how this aligns with [112.3], where the “preparation for grace […] has a necessity – not indeed of coercion, but of infallibility […] if God intends, while moving, that the one whose heart He moves should attain to grace, he will infallibly attain to it […]. […] man’s flight to God is by a Divine motion, which ought not, in justice, to fail.”
 [110.1] It would seem that, as the good, God cannot will evil for anyone, but it is not clear that his not appointing some to eternal salvation is neglect or a willing which is culpable: they are simply willed to the good proper to their nature, rather than to a higher good, and so the will of God is still all good. The higher good is gratuitous, and God owes it to no one. Thus there is a “common love, whereby He loves “all things that are”, and thereby gives things their natural being. But the second is a special love, whereby He draws the rational creature above the condition of its nature to a participation of the Divine good.” This would seem to follow from the fact that God does not commit multiple acts, but that his various acts are really manifestations of one act, which is multiply efficacious. God is simple, and so “the Divine act […] is simple and uniform” so that “by one simple act He administers great things and little.” [112.4]
 [113.2] “God’s love, considered on the part of the Divine act, is eternal and unchangeable; […] the effect of the Divine love in us […] is grace […].”
 So Oberman in his Age of Reform, 62: “If nature and supernature were bound together in such a way that nature’s end was necessarily a supernatural end, and if the church’s sacraments and revelation were the indispensable links between nature and supernature, then the medieval church, standing between man and God, nature and nature’s end, had a very basic claim on people and the temporal world. It was precisely such an assumption that underlay papal claims to temporal power.”