Martin Luther's Relation to Aristotelian Ethics
An Argument For Continuity
I have begun a significant writing project, which is expected to take the better part of a year, on Lutheran ethics. The focus of the work is primarily on the development of ethics among Lutheran thinkers after the Reformation, but there is some preliminary treatment of Luther’s own relationship to the ethical life. The following post is a section of this book that I am currently working on, which deals with the relation between Luther and the virtue ethics tradition. Luther’s sharp critiques of Aristotle in 1517 and 1518 have often been used to demonstrate a total break between Luther and virtue ethics, which poses a problem regarding Luther’s relation to later Lutheran authors, who are clearly within the virtue ethics tradition. This is especially notable in that Melanchthon commends Aristotle’s Ethics in the Apology of the Augsburg Confession, which is a Confessional writing, thus superseding any singular non-Confessional work of Luther for those who define Lutheranism as an ecclesiastical tradition, rather than a slavish adherence to every utterance of Martin Luther.
Does Luther Have an Ethical System?
Unlike Melanchthon, Luther never wrote a textbook that explicitly identified itself as a work of Christian ethics. There is no treatise or disputation that covers the topic in a systematic way, though several treatises and disputations of Luther’s address ethical themes. For this reason, it is doubtful that one can construct a consistent ethical theory directly from Luther. Luther was an occasional writer, addressing issues as they arose, and usually with a particular practical end in view, rather than constructing systems. When examining Luther’s thought, then, one must always be careful to identify the specific idea, theme, or argument that Luther identifies as he employs rhetorical critique. It is not right to abstract statements that Luther makes in response to a particular error he seeks to refute and treat them as absolute, indisputable principles that he universally employs. If Luther is read in that way, one is bound to find contradictions throughout his corpus.
This is important, especially in relation to the topic of virtue. It is undoubtedly true that there are writings of Luther, particularly in his early career, in which the reformer strongly opposes the Aristotelian virtue tradition. This is in seeming contrast with Melanchthon as well as nearly the entire Lutheran body of ethical writing in the following century, which stands firmly within the school of virtue ethics. This seeming incongruity has been explained in two contradictory ways. First, it has been argued that Luther and Melanchthon have irreconcilable positions on this point; Luther rejects virtue ethics, and Melanchthon promotes virtue ethics. Second, some contend that Luther’s opposition to Aristotelian virtue ethics was not a repudiation of virtue ethics as such, but of how they had been used as a means of meriting righteousness coram deo. A contextual reading of Luther’s statements about virtue helps clarify this dilemma.
Luther’s Critical Statements
Luther’s most critical statements toward Aristotle appear in his 1517 Disputation Against Scholastic Theology (LW 31, 12-13). Among the ninety-seven theses included in this disputation, theses forty through fifty-one set forth an argument against Aristotle. In thesis forty, Luther sets forth his primary claim in the following words: “We do not become righteous by doing righteous deeds but, having been made righteous, we do righteous deeds. This is in opposition to the philosophers.” While Luther had not yet fully formulated a mature Reformation understanding of justification by this point, he had committed to a strong Augustinianism, believing in the primacy of grace in producing good human actions. Obedience to God is only possible through God’s regenerative grace, and therefore, to claim that good deeds make the subject righteous through practice is to subvert the relation between grace and righteousness, making grace a reward for righteousness rather than its sole foundation. This leads Luther to conclude that Aristotle’s Ethics is “the worst enemy of grace,” since the Ethics was used in the schools to defend a neo-Pelagian form of works righteousness. In an oft-quoted passage in the disputation, Luther bluntly declares that “the whole Aristotle is to theology as darkness is to light.” It seems that one could not possibly iterate a clearer condemnation of Aristotelian virtue ethics than that.
In light of these statements, there are two significant questions to be answered here. The first is, who exactly is Luther speaking of when he condemns the “scholastics” throughout this writing? Second, what exactly is Luther’s theological concern, and do virtue ethics necessarily lead to that which Luther criticizes? Regarding the first point, Luther repeats four specific names throughout the treatise: Gabriel, Scotus, Ockham, and “the Cardinal.” The Gabriel mentioned is Gabriel Biel, often known as the last of the medieval scholastics, and “the Cardinal” identified by Luther is the nominalist French theologian Pierre D’Ailly. It is notable that Luther’s criticisms are not primarily directed toward St. Thomas Aquinas or any of the more Augustinian scholastics, but against the nominalist theologians who predominated in the latter part of the Middle Ages. This merits some discussion of exactly what some of these theologians taught.
Luther’s Relation to Late Medieval Nominalism
The nominalists made a distinction between the absolute power of God (potentia absoluta) and the ordained power of God (potentia ordinata). The absolute power of God is the ability of God to do anything that is not a contradiction. This absolute power is not exercised in every way, as there are all kinds of things that God could potentially do (ad extra) that he does not do. God could, for example, choose not to work by means of scientific laws and instead operate directly in the world, keeping plants alive without water, or creating new human beings ex nihilo, rather than through the ordinary process of conception and birth. The ordained power of God refers to the ways that God has chosen to work in the world. According to God’s ordination, plants need water, and human beings are conceived in wombs. These ordained ways of operating are not absolute, as God can suspend the ordinary operations of the world in order to perform a miracle.
In the theology of Gabriel Biel, God has set certain qualifications that human beings need to meet in order to receive grace according to the potentia ordinata. There is no intrinsic connection between particular human actions and the rewards (or punishments) given by God based on those actions. God has merely decreed that particular acts lead to certain consequences, whether positive or negative. In this ordained will, Biel argues that God has decreed that there is one thing necessary in order for a human being to enter into a state of grace: that a man does everything that is in him to dispose himself to a state of grace. This right disposition has both a positive and a negative element within it. Positively, one must actively strive after God. Negatively, one must remove all obstacles to this end. As God has decreed, when an individual does all that is in his power to direct himself toward God, he receives God’s grace.
Biel has an optimistic anthropology which differs heavily from Luther’s Augustinianism. For Biel, the human will remains fundamentally intact after the Fall, as by pure nature, human beings have the ability to love God and fulfill the Decalogue. When Biel discusses love toward God, which is an essential element of right disposition, he contends that a true love for God is not directed toward God because of his benefits. Instead, God must be loved for his own sake—not for what he gives. This pure love for God underlies everything for Biel, so that refraining from mortal sin alone, or partaking of the sacraments, does not assure salvation. Salvation necessitates pure love, which is impossible to identify with any certainty within one’s own life. While there are some internal signs that lead to what Biel calls “conjectural certainty” that one has entered into a state of grace, absolute knowledge that one has met the necessary conditions for salvation is out of one’s grasp apart from some supernatural immediate revelation. This is because the condition differs depending on the abilities of any specific individual. What is required of one may not be required of another, as one is required to do the best that they can, which is dependent upon the diversity of personalities and traits.
With this in view, the object of Luther’s critique in the 1517 disputation is quite clear. The first thesis in this disputation presents a defense of Augustine, and the second thesis provides an identification of the Pelagians as Augustine’s proponents. The following theses argue against the position of Biel that the human will remains free after the Fall, and that fallen men and women are able to love God by pure nature without regenerating grace. The whole disputation is a critique of what Luther perceives to be a new form of Pelagianism and a defense of Augustine regarding the primacy of grace. For Luther, there can be no spiritually good action which is not first preceded by grace; grace is never a reward for right disposition. There is nothing particularly new in these theses, as he presents the same basic arguments that are set forth in Augustine’s On the Spirit and the Letter, along with other anti-Pelagian writings. Luther accurately says of these theses that “we have said nothing that is not in agreement with the Catholic church and the teachers of the church.” None of the objections Luther presents regarding the use of Aristotle apply directly to Aristotelians like Thomas Aquinas, as Thomas is himself within the Augustinian tradition, contending that the theological virtues of faith, hope, and love are infused into the soul by divine grace, rather than merited on the basis of mere natural power or effort. My argument is not that Luther is a Thomist (such a position would be indefensible), but that the two views are not totally at odds with one another in the way that Luther and Biel’s views are.
In his work Luther and Late Medieval Thomism, Dennis R. Janz provides significant context for Luther’s conflict with Thomism, which shows that the two schools of thought are not as oppositional to one another as has sometimes been assumed. Luther first comes into conflict with Thomism through two authors who publicly criticized the reformer in 1518: Prierias and Cajetan. This conflict with Thomistic theologians is a primary focus of Luther from 1518 through 1522. In examining the content of Luther’s critique, Janz shows that Luther’s remarks about Thomism echo the anthropological concerns that formed his attacks on Biel and Ockham. Luther believed that Thomas affirms the human ability to obey the law by means of right reason alone. This portrays a serious misunderstanding of Thomas’s thought, as the Dominican writes within the same Augustinian tradition that Luther himself affirms. As Janz demonstrates, Luther shows no evidence of having read Thomas directly at any point during his career, and his interpretation of Thomas is almost certainly derived from the three interviews he engaged in with Cardinal Cajetan, the most well-known Thomist of his day. Cajetan held to a distinctively non-Augustinian interpretation of Thomas, formed by a reliance on Thomas’s earlier writings, as well as on developments in scholastic thought after Thomas’s death. It is precisely on the points where Cajetan departs from Thomas that Luther is most critical of him. What this means is that the relationship between Luther’s and Thomas’s theologies cannot be determined merely by a reiteration of Luther’s direct statements about the earlier writer, which are not based on a careful read of Thomas, but on secondhand interpretations received in the midst of heated conflict.
Luther’s Relation to Melanchthon
Regarding Luther’s relation to Melanchthon on the usefulness of Aristotelian philosophy, it is notable that Melanchthon wrote rather consistently on this subject throughout his career, rather than addressing the subject solely after Luther’s death. This is important because if Luther disagreed so strongly on this point, he had the opportunity to present objections, and never did so. This is evidenced in the Apology of the Augsburg Confession, in which Melanchthon makes precisely the same argument that Luther does in the Disputation Against Scholastic Theology regarding the nature of righteousness. In his defense of Article IV of the Augsburg Confession on the subject of justification, Melanchthon criticizes those who “teach that men merit the remission of sins by doing what is in them” and that God “necessarily gives grace to one thus working, by the necessity not of constraint, but of immutability” (Ap. IV. 9-11). The language of “doing what is in them” is taken from Biel directly, and the distinction between constraint and immutability is a reference to the potentia absoluta and ordinata distinction, also as used by Biel. Melanchthon identifies all the same errors Luther did earlier and uses many identical arguments. Where Melanchthon differs from Luther is in his evaluation of Aristotle.
Melanchthon builds on Luther’s argument by making a distinction that allows him to both affirm Luther’s critique of the theological use of Aristotle and to simultaneously vindicate Aristotle. Melanchthon differentiates between a “righteousness of reason” (iustitiam rationis) and “Christian righteousness” (iustitia Christiana) (Ap. IV. 9-12). These two kinds of righteousness are distinguished as related to the disciplines of philosophy and Christian theology (philosophiam et Christi doctrinam) (Ap. IV.12) respectively. Regarding civic or philosophic righteousness, “Aristotle wrote concerning civil morals so learnedly that nothing further concerning this need be demanded” (Ap. IV.14). By making a strong distinction between Christian righteousness, which is always initiated by grace, and a philosophic righteousness, which is discoverable through reason and achievable through practice, Melanchthon retains a virtue ethic within an Augustinian framework, praising Aristotle while also denying that Aristotle is useful in explaining saving righteousness. Philosophy and theology are both essential academic disciplines, but must not be conflated.
Not only does Melanchthon distinguish righteousness into these different kinds, but Luther also adopts these distinctions in his own writings. In a passage at the beginning of his 1535 Lectures on Galatians, Luther writes:
For righteousness is of many kinds. There is a political righteousness, which the emperor, the princes of the world, philosophers, and lawyers consider. There is also a ceremonial righteousness, which human traditions teach, as, for example, the traditions of the pope and other traditions. Parents and teachers may teach this righteousness without danger, because they do not attribute to it any power to make satisfaction for sin, to placate God, and to earn grace; but they teach that these ceremonies are necessary only for moral discipline and for certain observances. There is, in addition to these, yet another righteousness, the righteousness of the Law or of the Decalog, which Moses teaches. We, too, teach this, but after the doctrine of faith. (LW 26, 4)
These kinds of righteousness are all active to some degree, and are distinguished from Christian righteousness that is passive. In Luther’s mature works, one does not find the kinds of absolute statements about Aristotelian conceptions of virtue that are present in the 1517 disputation or in his 1518 Heidelberg Disputation. This is because Luther’s concern is not to downplay the need for moral effort, or to deny that there is any sense in which habituation is effective, but simply to differentiate between passive righteousness and all forms of active righteousness, including philosophic righteousness.
In light of this, it must be pointed out that Luther himself recommended the use of Aristotle in education, which is apparent in his inclusion in the curriculum at Wittenberg, alongside several other authors in antiquity. Of all classical authors, Luther cites Aristotle most extensively, with Carl Springer (“Martin’s Martial: Reconsidering Luther’s Relationship with the Classics”) pointing to 700 references to the philosopher in Luther’s corpus, more than doubling citations from Cicero (the second most cited author of antiquity by Luther). These citations are not all positive, by any means, but many are. Matthew Mason points to a particularly interesting citation of Aristotle, which occurs among the last of Luther’s Lectures on Genesis, which were a series of talks given just prior to Luther’s death. In this passage, Luther positively cites Aristotle’s conception of equity and of virtue as a middle path between extremes. Luther employs this Aristotelian definition against the perceived legalism of his opponents, showing that the reformer does not see Aristotle as an inherent enemy of grace, but a tool that could be employed against those who despise grace. This all does not mean that Luther was as favorable to Aristotle as Melanchthon was, but it does show that the strongly anti-Aristotelian rhetoric of early Luther is not so pronounced at the end of his life, and that he cited Aristotle favorably when his work merited a positive evaluation.
Conclusion
In summary, Luther’s strongest critiques of Aristotle appear in his early career, prior to his fully-formed Reformation theology, and they are pointed specifically at the way in which Aristotle’s ethics are used in relation to Christian righteousness (which is passive rather than active). It is this same concern that drives his criticisms of the Thomistic use of Aristotle, which Luther does not understand on Thomas’s own terms, but through the interpretation of Thomas that was used by Cardinal Cajetan as an anti-Reformation polemic. Luther’s closest colleague, Philip Melanchthon, incorporates a strong Aristotelianism into his thought while distinguishing Christian righteousness from philosophic righteousness, which is stated explicitly in one of the Confessional writings of the Lutheran church (the Apology of the Augsburg Confession). Luther adopts this Melanchthonian distinction between passive righteousness and philosophical righteousness in his 1535 Lectures on Galatians. In his final lectures, Luther cites Aristotle positively on the subject of ethics, demonstrating that there was not complete discontinuity between the two thinkers.

Thank you Dr. Cooper for a very interesting piece. Luther’s interaction with the scholastics has always interested me and your article helped me understand it better.
I think it is interesting that Luther particularly went after Nominalist theologians in light of what I have heard of Luther himself holding Nominalist tendencies. Am I misinformed on Luther being defined as a Nominalist?
Looking forward to this!