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  • Jared Mindel

Theology: Theoretical or Practical?

Theology, the study of God and divine things, is the paramount discipline because it concerns the highest and most sublime realities. All Christians should aim to be good theologians, as all are called to believe and confess the truth. Yet, there is no Christian consensus regarding the classification of theology as a genus. In other words, there is no agreement about whether theology is a theoretical or practical discipline. This is an important matter, as it shapes how we understand the purpose of theology. Our primary question in this article, therefore, is whether theology may be classified as a speculative science or a practical habit.

Thomas Aquinas: Theology a Speculative Science

The Thomists, represented by Thomas Aquinas and his followers, classify theology as a speculative science. Categorizing theology as a science may initially appear unconventional; however, it is important to note that the medieval scholastics do not confine the term science exclusively to inductive disciplines such as chemistry or physics. Instead, the scholastics define a science as “the certain intellectual knowledge of something in its causes; universal, demonstrated, organized knowledge of facts and truths and the reasons or causes of these.”[i] A speculative science may be defined as a science that is studied for its own sake, rather than for the sake of some action or practice. In this context, the term speculative conveys a connotation not of conclusions drawn from conjecture or guesswork, but rather aligns with the synonymous meaning of theoretical. Therefore, the final cause or aim of a speculative science is simply the knowledge that one gains from study. Aquinas argues that theology may be classified more as a speculative science than as a practical science, a science that is studied for the sake of some action, because theology primarily studies God, rather than human operations.[ii] Aquinas writes that “among the philosophical sciences, one is speculative and another practical, nevertheless sacred doctrine includes both . . . still, it is speculative rather than practical because it is more concerned with divine things than with human acts.”[iii] He, therefore, acknowledges that theology has an aspect of practicality, but he believes that theology leans towards being speculative because the object of theology is God as opposed to man’s work.

As a consequence, Aquinas believes that the final cause of man consists principally in the contemplation of God. He writes, “man’s ultimate felicity consists only in the contemplation of God.”[iv] Aquinas argues that because man’s capacity for reason distinguishes him from other creatures, his natural operation is contemplation. The final cause of man, therefore, is the contemplation of the most noble things, which are divine things as received in the beatific vision. Therefore, man’s primary enjoyment in eternity is intellectual. Man finds his rest in the contemplation of God, so the enjoyment of God and the contemplation of God are fundamentally one intellectual act. Aquinas comments, “Since happiness is the proper good of an intellectual nature, happiness must pertain to an intellectual nature by reason of what is proper to that nature. . . . Therefore, happiness, or felicity, consists substantially and principally in an act of the intellect rather than in an act of the will.”[v] 

Johann Gerhard: Theology a God-Given Habit

Johann Gerhard develops several objections to Thomas’s view that theology is a science. First, Gerhard argues that for any discipline to be categorized as a science, it must be demonstrable by “internal and inherent principles,”[vi] but matters of the faith are not demonstrated. Theology is not demonstrated through such principles, but instead believed in by virtue of the external principle of God’s authority, so we cannot define theology as a science. Aquinas admits that certain key aspects of theology can only be known by revelation. He comments the following with respect to knowledge of the Trinity: “The trinity of divine persons is distinguished by origin of generation and procession. Since, therefore, man cannot know, and with his understanding grasp that for which no necessary reason can be given, it follows that the trinity of persons cannot be known by reason.”[vii] Second, Gerhard comments that the primary subject of theology is Christ, and we cannot have knowledge of him by pure demonstration, so theology must not be a science. We have knowledge of Christ from his teachings and the words of the apostles, not from reason. This is a very similar argument to the first, but it draws our attention to how theology is principally drawn from the revelation of Christ. Once again, the issue is whether a science can exist where the principles are established by external authority instead of by “internal and inherent principles.”[viii] Third, Gerhard notes that sciences move the intellect from the understanding of certain principles to the factual knowledge of the conclusions drawn from them. Knowledge is thus the principle of science, but in theology knowledge is the goal, not the principle. Therefore, theology is not properly scientific. Gerhard’s final objection is that a falsehood can underlie a science, but a falsehood cannot underlie faith. Interestingly, he cites Aquinas for this argument.

Gerhard then establishes that theology is more practical than speculative because the end of theology is not knowledge as such, but action. The final cause of theology is not merely speculation over the divine nature and contemplation of what God has revealed, but the appropriation of God’s gifts into a life of faith. The theologian seeks to understand and live a life pleasing to God by loving his neighbor and being conformed to the image of Christ. Gerhard and the Lutherans are not opposed to discussions of revealed truths in academic or speculative settings, but they recognize that this is not the core of the Christian life. While knowledge of the true faith is necessary, it alone is not sufficient for salvation. The Lutherans historically critiqued the monastic orders not because they sought knowledge of God, but because they isolated themselves from the world, not serving their neighbors as we ought. The monks hid themselves in cloisters and devoted themselves to endless speculation and works they imagined held value but in truth were vanity. A true theologian studies theological truths and lives them out, loving his neighbor and offering himself as a living sacrifice before God.

The Lutheran scholastics generally follow Gerhard by defining theology as a practical habit, though David Hollaz is a notable exception because he calls theology “the science of God and divine things communicated to intelligent creatures by God.”[ix] Revere Franklin Weidner also dissents from Gerhard, believing that theology is a science. He writes,

The objection, also, has been made that theology cannot be regarded as a science because the truths that are therein contained are not proper objects of knowledge, because they are to be apprehended only by faith. But faith and knowledge do not stand in relation to each other, as to preclude the possibility of theological science. Faith is only a higher sort of knowledge.[x]

That said, Weidner appears to agree that theology is primarily practical, as he writes, “the final aim of theology does not lie in the science itself, still less in its students alone, but entirely and completely in the up-building of the kingdom of God in and around them, and in the glorification of God.”[xi] We may cautiously agree with Heinrich Schmid’s summary of the position of seventeenth century Lutherans, though we must also admit that this position is not unanimous across orthodox Lutheran theologians. Schmid writes:

Frequently Theology is called a practical habit. As it appeared to the theological writers that the expression science gave too much prominence to the mere acquaintance with the subjects concerned, they therefore sought a definition in which it should be distinctly expressed that by Theology there was meant a divinely-wrought knowledge, such as urged its possessor to put to practice what he learned. The dogmaticians follow the medieval mystics and some scholastics in defining Theology as “wisdom” rather than “science,” thus emphasizing the need of spiritual illumination in the apprehension of its truths.[xii] 


The Lutheran scholastics do not delve extensively into the examination of the priority of the will or intellect in beatitude, but David Hollaz affirms that “our eternal and highest blessedness consists in the perfect sight and enjoyment of God. The former is an operation of the intellect, the latter of the will.”[xiii] Consequently, the enjoyment of God is not primarily an intellectual act but a volitional one. This perspective aligns with the Lutheran belief that theology is a practical habit rather than a speculative science. While knowledge of God possesses intrinsic value, its utmost significance lies in being a necessary condition for human salvation. In eternity, knowledge of God and enjoyment of God are distinct acts for the blessed. Although making conclusive statements about the thoughts of every Lutheran scholastic on the matter is challenging, we may cautiously assert that at least one representative of the tradition teaches that the enjoyment of God is an operation of the will, and this view logically flows from the Lutheran classification of theology as a practical habit, rather than a speculative science.


Thomas Aquinas and Johann Gerhard differ regarding theology, specifically with respect to its status as a speculative science or practical, God-given habit. Aquinas sees theology as primarily speculative because it concerns divine truths, while Gerhard sees theology as primarily practical because it spurs a life of faith and action in the student. That said, some of the disagreement may be attributed to ambiguity in definitions, as Aquinas is willing to grant that something demonstrated on the basis of revealed principles is a science, while Gerhard is not. Despite their differences, each theologian, brilliant in their own right, emphasizes the value of theology for the sake of knowledge, and for the sake of works. Both are willing to call theology a kind of wisdom, with Aquinas writing “this doctrine is wisdom above all human wisdom; not merely in any one order but absolutely”[xiv] and Gerhard echoing “we indeed admit that, if we must assign to theology some genus from all the intellectual conditions that Aristotle enumerates, among them all, wisdom most closely approximates its nature.”[xv]

[i] Bernard Wuellner, “Science” in Dictionary of Scholastic Philosophy (Milwaukee: Bruce Publishing, 1956), 112.

[ii] Thomas Aquinas, Summa Theologiae, 1.1.4.

[iii] Ibid.

[iv] Thomas Aquinas, Summa Contra Gentiles, 3.37.

[v] Ibid., 3.26.

[vi] Johann Gerhard, On the Nature of Theology and Scripture, ed. Benjamin T.G. Mayes, trans. Richard J. Dinda (St. Louis: Concordia Publishing, 2009), Preface.

[vii] Aquinas, Summa Theologiae, 1.32.1.

[viii] Gerhard, Preface.

[ix] Heinrich Schmid, The Doctrine of the Evangelical Lutheran Church, 3rd ed., rev., trans. Charles A. Hay and Henry E. Jacobs (Minneapolis: Augsburg Publishing, 1899), 16.

[x] Revere Franklin Weidner, An Introduction to Doctrinal Theology, 2nd ed., rev. (Rock Island: Augustana Book Concern, 1888), 27.

[xi] Ibid., 22.

[xii] Schmid, 17-18.

[xiii] Ibid., 666.

[xiv] Aquinas, Summa Theologiae, 1.1.6.

[xv] Gerhard, Preface.


1 Comment

May 20

Great article. What strikes me as bizarre is that it almost sounds like Aquinas is arguing for faith alone here. By saying that "happiness, or felicity, consists substantially and principally in an act of the intellect rather than in an act of the will," he seems to align with those who treat salvation as merely accepting a certain set of facts as true. It is strange to hear the shaper of late medieval Catholicism argue like a modern evangelical fundamentalist. His mistake is in assuming that our ultimate happiness is intellectual. Happiness is when one gets what one desires; ultimate happiness is when one desires what is proper, and then achieves it. In other words, felicity consists of the will…

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