In Defense of Natural Theology

Issue
Natural theology, the concept that God has intentionally revealed Himself and humanity can gain knowledge about Him from His natural revelation without the use of the Scripture, has been a theme of discussion that ranges from the early church to the present day. Even Scripture itself testifies that “The heavens are telling of the glory of God; and their expanse is declaring the work of His hands.”[1] Yet while some scholars maintain that this is one of the most vibrant areas of Christian theology, still other evangelicals feel that natural theology is blasphemy and the height of human arrogance. Augustine, Aquinas, Barth, Brunner, and many other Christians throughout ecclesiastical history have considered this aspect of theology important, and therefore they made very scriptural arguments either for or against this particular branch of theology. Natural theology, properly understood and given certain modifications to the traditional version, does have an important place in the realm of theology within evangelical Christianity.
Positions
The oldest position of traditional natural theology finds many important allies among the theological greats of Christianity. Thomas Aquinas made strong arguments for the legitimacy of natural theology via what has come to be called the Five Ways. In five separate ways, Aquinas demonstrates that real knowledge about God is possible outside of Scripture. Alexander Hall summarizes the five ways quite well when he states
The Five Ways rely on five observations: things that are in motion, there exists an order of efficient causes where one entity moves another, contingent entities exist, among beings we find varying degrees of perfection, and unintelligent entities exhibit seemingly end-directed activity. Aquinas argues that these phenomena disclose the existence of a first mover, first efficient cause, etc., and identifies these entities with God.[2]
In other words, Aquinas understood that humans, with the help of reason, could construct arguments for the existence of God based on philosophical observations from nature itself. John Calvin himself, though some scholars disagree on the extent, supported the concept of natural theology. Calvin stated within the Institutes of the Christian Religion that
There are innumerable witnesses in heaven and on earth that declare the wonders of his wisdom. Not only those more arcane matters for the closer observation of which astronomy, medicine, and all of natural science (tota physica scientia) are intended, but also those which force themselves upon the sight of even the most unlearned and ignorant peoples, so that they cannot even open their eyes without being forced to see them.[3]
Here Calvin argues that even the most non-intellectual people possess the ability to see clearly the evidence of God. In this particular instance, Calvin states that humans ought to gain an appreciation for God’s wisdom when they behold the attributes of God found within creation. While Aquinas and Calvin understood natural theology as beneficial to Christianity, they are not the only perspective on the matter.
Several theologians have developed critiques and objections to the validity of natural theology. Karl Barth, in his famous debate with Emil Brunner over this issue, stands as the primary prosecutor of natural theology. Barth held the notion that knowledge about God apart from special revelation violated sola gratia. Millard Erickson describes the point of view of Barth when he states
Barth is very skeptical of the view that humans are able to know God apart from the revelation in Christ. This would mean that they can know the existence, the being of God, without knowing anything of his grace and mercy. This would injure the unity of God, since it would abstract his being from the fullness of his activity. A human who could achieve some knowledge of God outside of his revelation in Jesus Christ would have contributed at least in some small measure to his or her salvation or spiritual standing with God. The principle of grace alone would be compromised.[4]
Here Erickson explains that Barth understood the core of natural theology to argue for a works-based salvation. If knowledge of God can be achieved without knowing Christ in Scripture, then he or she would have a small role in their own salvation. Since one of the main tenets of natural theology is that true knowledge about God can be gleaned from nature apart from Scripture, Barth maintained that natural theology exemplified human arrogance because it appeared to violate the intrinsic need of humanity for the grace of God.
Some more modern theologians have attempted a sort of via media when discussing the viability of natural theology. Thomas Torrance, a Scottish theologian that agreed with the analysis of Barth on natural theology, redefines natural theology in such a way that it can stand against the objections of Barth. McGrath illustrates the new version of natural theology argued for by Torrance when he states
Torrance can therefore be thought of as moving natural theology into the domain of systematic theology, in much the same manner as Einstein moved geometry into the formal content of physics. The proper locus of natural theology is not debate about the possibility of hypothetical knowledge about God, but within the context of the positive and revealed knowledge of creator God.[5]
Torrance, as McGrath rightly illuminates, shifts the definition of natural theology away from independence from the revelation of God in Scripture to a type of systematic theology. To clarify, Torrance thought natural theology viable because the Word of God taught that general revelation displays some knowledge about God. Since this version of natural theology relies on other forms of revelation, Barth would not have disagreed with this definition.
Support
Natural theology does have a rightful place in theological study once the scope and limits of this aspect of theology are properly examined. Clearly some knowledge about God is revealed in nature as can be seen from the teachings of Scripture. Aside from Psalm 19, the Apostle Paul argues for revealed knowledge of God in nature. In Romans chapter one, Paul argues “For since the creation of the world His invisible attributes, His eternal power and divine nature, have been clearly seen, being understood through what has been made, so that they are without excuse.”[6] This passage is commonly cited in support of general revelation, the appropriate setting for natural theology. Wayne Grudem defines general revelation when he states “The knowledge of God’s existence, character, and moral law, which comes through creation to all humanity, is often called ‘general revelation’ (because it comes to all people generally).”[7] While natural theology constitutes a form of general revelation, notice that the definition that Grudem gives does not say that general revelation is absolute proof of God’s existence. General revelation is merely knowledge of God. This is due to the fact that general revelation comes to humanity from God, but has an intellectually sinful reception. Again, the Apostle Paul explains
For though they knew God, they did honor Him as God or give thanks, but they became futile in their speculations, and their foolish heart was darkened. Professing to be wise, they became fools, and exchanged the glory of the incorruptible God for an image in the form of corruptible man and birds of the air and four-footed animals and crawling creatures.[8]
Paul states that sinful humanity did actually gain knowledge about God, but sinfulness pushes them toward idolatry. Because the sin of humanity darkens this knowledge, Bruce Demarest explains that “Instead of proving salvific, general revelation serves only to condemn and to establish guilt-worthiness before God.”[9] Demarest means here that general revelation is not involved in the salvation process, but it does have other uses. Since natural revelation is a form of general revelation, it follows that natural theology also possesses no salvific truth.
Apart from establishing the guilt of humanity before God, natural theology does have other uses that have importance in Christian theology. It does not, as in the traditional view, necessarily prove the existence of God. As James Barr notes “We may question whether all natural theology seeks to ‘prove’: it may, on the contrary, merely indicate, merely register, what people think about God.”[10] McGrath notes the view of Alvin Plantinga who also does not believe that natural theology proves the existence of God when he states “In other words, natural theology is not intended to prove the existence of God, but presupposes that existence; it then asks ‘what should we expect the natural world to be like if it has indeed been created by such a God?’”[11] Linking the ideas of Barr and Plantinga to Scripture, since the knowledge from general revelation and natural theology is sinfully received, only after the illuminating work of the Holy Spirit after conversion does this information point to the existence of God. While this seems to restrict the usefulness of natural theology, Demarest illustrates several beneficial aspects of natural theology as contained in general revelation when he states
But general revelation serves several salutary ends. (1) It accounts for the presence of the truth wherever found in human experience and culture, including valid elements in the non-Christian traditions. (2) The universally implanted moral law provides the only authentic basis by which good and evil can be distinguished. The fact that good is enjoined and evil proscribed provides society with a viable moral framework. (3) Since all people possess rudimentary knowledge of God, Christian witnesses are assured when speaking to the unconverted that the notion of God is not meaningless.[12]
Here Demarest lists three important effects of doing natural theology in the correct manner. It allows Christians to explain how other religions do have at least some truth in them. Natural theology also explains how all of humanity has similar concepts of right and wrong. This particular point, known as the moral argument, is discussed in C.S. Lewis’ classic Mere Christianity. Lastly, it gives encouragement to believers because natural revelation acknowledges that unbelievers do have some knowledge about God, even if this knowledge has been twisted by sin.
Other observations that natural theology supports are the claims made within the special revelation of Scripture. When humanity can observe in nature and in themselves the phenomena listed within passages like Psalm 19, Job 36-37, and Romans 1, this lends weight to the authority of the Bible. Natural theology, under the umbrella of natural theology, works with the revelation of God in His Word. Rodney Stiling relates this cooperation between Scripture and natural theology when he states
Very little of the biblical text refers specifically to nature or natural phenomena, but in those few places where Scripture makes reference to nature, Christians committed to the time-honored notion that the one God is the author of both a general revelation in nature and a special revelation in Scripture would insist that these ‘two books’ in some real sense actually agree.[13]
Stiling argues here for what must be the proper relationship of natural theology and Scripture. Natural theology gives knowledge about God, but it works with Scripture to accomplish this.
Objections
The primary theological objection to natural theology derives from the debate of Barth with Brunner. Describing one serious aspect of the objection concerning natural theology, McGrath, quoting Torrance, relates the critique of Barth when he states
Epistemologically, then, what Barth objects to in traditional natural theology is not any invalidity in its argumentation, nor even in its rational structure, as such, but its independent character – i.e. the autonomous rational structure that natural theology develops on the ground of “nature alone,” in abstraction from the active self-disclosure of the living and Triune God (…).[14]
While this critique of Barth is justified in terms of traditional natural theology, if it is reclassified as a part of traditional systematic theology that is dependent on the Word of God for understanding and is studied in Christian community, then this objection deserves dismissal. McGrath demonstrates the appropriate understanding of natural theology as described by Torrance when he states
So it is with natural theology: brought within the embrace of positive theology and developed as a complex of rational structures arising in our actual knowledge of God it becomes ‘natural’ in a new way, natural to its proper object, God in self-revealing interaction with us in space and time.[15]
Here McGrath and Torrance rightly assert that if natural theology is understood as part of a systematic theology that stands in a supportive role to the special revelation of Bible, then the independence that Barth noted in traditional natural theology has changed into an utter dependence on God. Scripture clearly teaches that God has revealed Himself in nature and the humans He created, but this knowledge cannot save without a dependence upon the saving work of Jesus Christ that proceeds out of the accounts of Scripture and not nature. Therefore, natural theology exists as an aspect of general revelation.
Alvin Plantinga, an evangelical philosopher in the Reformed tradition, gives a philosophical objection to natural theology. Though his objection is complex to understand, his problem with natural theology is rooted in the definition of traditional theology. McGrath correctly interprets the view of Plantinga when he states
Natural theology supposes that belief in God must rest upon an evidential basis. Belief in God is thus not, strictly speaking, a basic belief – that is, something which is self-evident, incorrigible or evident to the senses. It is therefore a belief which requires to be itself grounded in some more basic belief. However, to ground a belief in God upon some other belief is, in effect, to depict that latter belief as endowed with a greater epistemic status than belief in God. For Plantinga, a properly Christian approach is to affirm that belief in God is itself basic, and does not require justification with reference to other beliefs.[16]
According to the understanding of Plantinga, the goal of traditional natural theology is to prove the existence of God via observations in creation. These observations, however, if they are understood to prove the existence of God, are given a higher epistemological value than belief in God Himself. To answer this objection, traditional natural theology seems to affirm that argument that Plantinga makes. However, if the definition of natural theology changes to mean that it exists only as a part of the revealed theology about God that is dependent on His Word, then the idea of James Barr that natural theology does not attempt to “prove” the existence of God maintains the assertion of Plantinga that belief in God is basic. This basic belief, in turn, is not grounded in natural theology but supported by it.
The concept of natural theology has maintained an important role throughout the broad extent of ecclesiastical history. Though its traditional form does have both theological and philosophical problems with serious ramifications, the usefulness of natural theology can preserve with a change of its definition and purpose.
[1] Psalm 19:1 NASB.

[2] Alexander W. Hall, Thomas Aquinas and John Duns Scotus: Natural Theology in the Middle Ages (New York, NY: Continuum Publishing, 2007), 53.

[3] Alister E. McGrath, The Christian Theology Reader (Malden, MA: Blackwell Publishing, 2001), 98.
[4] Millard J. Erickson, Christian Theology (Grand Rapids, MI: Baker Books, 1998), 188-189.
[5] Alister E. McGrath, Christian Theology: An Introduction (Malden, MA: Blackwell Publishing, 2001), 217.
[6] Romans 1:20 NASB.
[7] Wayne Grudem, Systematic Theology: An Introduction to Biblical Doctrine (Grand Rapids, MI: Zondervan, 1994), 122-123.
[8] Romans 1:21-23 NASB.
[9] Bruce A. Demarest, “General Revelation,” in Evangelical Dictionary of Theology, ed. Walter A. Elwell (Grand Rapids, MI: Baker Academic, 2001), 1021.

[10] James Barr, Biblical Faith and Natural Theology (New York, NY: Oxford University Press, 1993), 2.
[11] McGrath, Christian Theology: An Introduction, 218.
[12] Demarest, “General Revelation,” 1021.

[13] Rodney L. Stiling, “Scriptural Geology in America,” in Evangelicals and Science in Historical Perspective, eds. D.G. Hart, David N. Livingstone, Mark A. Noll (New York, NY: Oxford University Press, 1999), 177.
[14] McGrath, Christian Theology: An Introduction, 216.

[15] Ibid., 217.
[16] Ibid., 218.