2. The use and place of natural theology in the Christian context: Du Moulin and Turretin. The somewhat varied approach of the Reformed orthodox to the question of natural knowledge of God, particularly the use of a threefold paradigm of natural, scriptural, and evangelical or natural, legal, and evangelical, like Calvin’s distinction between the natural knowledge of God in creation, apart from the aid of Scripture, and the natural knowledge of God available to Christians with the aid of Scripture, sets a series of boundaries on the usefulness of natural theology—boundaries that are observed and developed by the Reformed orthodox.
Du Moulin’s foundational treatment of this problem manifests considerable respect for the mind, speaking of it as the greatest faculty of the soul and of knowledge of the truth as the “principal ornament and perfection of the understanding.” The greatest height of understanding, moreover, is the knowledge of God. We note here the traditional bipartite view of man as body and soul, the latter being the inclusive term comprising the various spiritual faculties as its organs. Du Moulin’s respect for the powers of the mind is tempered, however, from the very outset of his argument by his view of the necessity of revelation: because God is not an object to be perceived but is the fountain of light by which man perceives all things, “God cannot be known … unless he infuse our souls with true knowledge of himself.” (This language of divine illumination, it should be noted, hardly fits the explanation of Protestant scholasticism as utterly Aristotelian: the language belongs definitively to the Augustinian tradition and its philosophically realist, somewhat platonizing approach to the problem of knowledge. What is more, among the medieval scholastics this approach is found not in Aquinas but in Bonaventure and various Augustinian theologians.)
This necessity of revelation leads Du Moulin to make a distinction between reason and revelation, philosophical concepts and theological doctrines. That man has an inherent knowledge of God is demonstrated both by pagan religion and by his general acceptance of the laws deduced from nature. Philosophers, furthermore, have deduced conceptions of God as Unmoved Mover, as first efficient cause, as Creator and Orderer of the world. Because of this knowledge of God apart from scriptural revelation, Du Moulin sees the need to elaborate upon man’s natural ability and define its limits. In the first place, natural knowledge of God is not entirely idolatrous—even though it has been put to wrongful use. Nature conveys some true knowledge of God to man, even if it is insufficient.
Even so, natural theology contains the idea of God as “the most perfect Being, from whom flows and on whom depends all entity and perfection.” From this definition follow the attributes of eternity, simplicity, and wisdom. If pagan religions show the sinfulness and idolatry of the wrongful use of this natural knowledge of the divine, philosophy can manifest the more positive ability of the natural man to conceive of God rightly. Philosophy can state the perfections of God, albeit in an imperfect manner. What the natural man lacks is the pure knowledge of God as revealed in his Word. A supernatural revelation is necessary if there is to be any true religion. It alone provides true, saving knowledge. It alone teaches true worship of God. The two components of true religion, knowledge and observance, must rest upon supernatural revelation. The entire discussion of the positive elements of natural theology stands, therefore, within the bounds of the Reformed paradox of the fractured remains of the imago Dei and the gift of virtues by common grace. Man’s conscience still provides a basic knowledge of the Law, nature still mediates some sense of the divine existence and command, and God still nurtures civic virtues—but none of these gifts is of any soteriological significance.
Du Moulin elaborates further upon this problem: reason and the law in nature provide knowledge of God as Creator, as master of life, and as giver of the requirements for right regulation of life. They also give a vague notion of what God is in himself, apart from his relation to external objects. Here Du Moulin clearly allows, albeit in a limited degree, for a metaphysical theory drawn out of nature. Reason and law also give man a sense of terror, an awareness of sinfulness, and a consciousness of just punishment. Yet a definite limit is set upon man’s knowledge of God—the corruption of his nature. Indeed, Du Moulin can go so far as to state that without the gospel, all knowledge of God and his works is useless speculation (no matter how correct) and a burden upon the conscience. Only the gospel reveals God as he wills to be toward man—as Father and Redeemer. The problem is not so much the utter unavailability of natural knowledge of God, then, as its inefficacy.
These statements lead Du Moulin to set forth the basic tenets for Christian theological anthropology, including especially the problem of the relation of the fall to the image of God in man. As first created, in God’s image, man was characterized by holiness and righteousness. Such was the imago Dei in its purity—a spiritual rectitude and a basis for communion with God. Then man “revolted from God of his own accord and by the suggestion of the Devil, whereupon sin came into the world and by sin death and malediction.” The imago Dei was not totally lost, but disfigured by sin so that there remains in every man some sense of the divine and a small seed of honesty and justice. There can now be no complete and saving knowledge of God through reason or nature, but because of the remnant of knowledge and because of our perception of the Law, we are all left without excuse in our sins. Thus, the entire anthropological and soteriological structure of Reformed theology must be brought to bear on the prolegomena, to the end that the initial epistemological statement of the system recognizes the impossibility of saving knowledge apart from the divine initiative. Despite the great respect he manifests for reason and philosophy throughout his treatise, Du Moulin, like Aretius—and, for that matter, like Calvin—concludes that revelation supplies man’s only hope: the epistemological problem is surmounted only in Christ, only in the One who reveals God as Father.
Du Moulin and his orthodox brethren, therefore, were unable to develop a theological epistemology without adumbrating their subsequent soteriological arguments, the primary point at issue being the theme of the duplex cognitio Dei. Du Moulin points out that, for the sake of man’s salvation, God sent his only begotten Son into the world to be united with human flesh. The Son, who is one God with the Father and the Holy Spirit, assumed human nature “without diminution of the divinity or mixture of the natures.” We note here the trinitarian ground motif of Reformed thought as well as the distinctive christological pattern with its emphasis on the divine transcendence. Christ, as the God-man, is the Mediator who joins and therefore reconciles these otherwise disparate extremes. In his human nature, writes Du Moulin, the Son of God performed the work of redemption, fulfilling the laws and making satisfaction for sin. He is the Author of eternal life to all who believe in him, for in him we are made sons of God through faith and by the “Spirit of Adoption.”
Du Moulin can therefore write, “… though God inhabits inaccessible light, he has made himself visible in some manner in his Son, who is the image of invisible God and God with us. Whosoever endeavours to come to God by any other way shall find him a Judge and not a Father.” The duplex cognitio Dei thus creates a paradox of the union and disunion of philosophy and theology in the great orthodox systems: on the one hand, God is the fountain of light by which we perceive all things, while on the other we cannot truly receive this divine light apart from Christ. Thus—if as Calvin said—knowledge of God and knowledge of self are intimately related, there can be no truly useful unregenerate knowledge. Philosophy, although it is a crucial adjunct to theology, stands under judgment, and even the nominally nonsoteriological loci of the system cannot be understood without faith. Again we see that the prolegomena are not an isolated point of departure but in fact depend upon the system they propose to ground.
The impact of the duplex cognitio Dei is stronger in some systems than others. In the era of the Reformation, Calvin and Viret mark the high point of its influence whereas Musculus and Vermigli develop somewhat different perspectives on the problem and are more open to natural theology. In the era of early orthodoxy the situation is similar: the duplex cognitio Dei is powerfully enunciated by Du Moulin and Polanus, while its influence is less apparent in the works of Scharpius, Gomarus, Alsted, and Walaeus—although each of the latter sets up barriers to the use of natural theology. Even so, in the high orthodox era, Heidegger and van Mastricht stand out as holding to a clear separation between natural and supernatural theology, while Turretin and Pictet see a vague promise in Christian philosophy. Turretin, moreover, can echo strongly the language of the duplex cognitio Dei.
Turretin can argue that salvation, after the fall, depends upon “the revealed Word of the Law and the Gospel.” The issue, argues Turretin, is not the existence of natural theology or natural religion: “we may admit, indeed, some sort of natural theology arising from the light of nature, upon which supernatural theology may be built—for example, that God exists, that God is to be worshipped.” The issue against the Arminians, is that such natural religion or natural theology cannot provide adequate or proper foundations (principia adaequata et propria) for true religion:
Wherefore Curcellaeus wrongly distinguishes faith in God from faith in Christ, as if the former is absolutely necessary to salvation, the latter only the result of divine revelation; for there can be no true and saving faith in God, that is not conjoined with faith in Christ, John 14:1. For we are unable to believe in God unless it is through Christ.
Ultimately, then, natural theology is not a foundation for true knowledge of God, even though it contains some truth. Turretin does not elaborate how this natural theology can be “built” upon—since it is clear that no one can move from natural to supernatural theology apart from the gracious revelation of God in Christ. He may have in mind a pedagogical or legal use of natural theology as described by Charnock and corresponding with the Reformed doctrine of the threefold use of the Law, or he may be pointing, much as Pictet would, toward an initial use of the proofs of God’s existence in Christian theology, and therefore toward the beginnings of a more rationalistic theology. In either case, however, a sharp line remains between the nonsaving character of natural theology and the salvific character of supernatural theology. At no point is there a clear movement of Reformed theology toward rationalism—rather, we find, in the spectrum of opinion on natural revelation and natural theology, a consistent concern to identify the distinctively soteriological character of Christian doctrine, so that the usefulness of natural theology, even as written by the regenerate, is questioned.
This conclusion carries even in those few places where the seventeenth-century orthodox do in fact speak of a natural basis of some sort for supernatural theology. We have already cited one such passage from Turretin: in his discussion of the role of reason in matters of faith, Turretin can also acknowledge a few “rays of natural light and certain first principles, the truth of which is unquestionable” that remain in the sin-darkened human understanding. These truths, Turretin continues, are not only true in the context of nature, but also in the context of grace and the “mysteries of the faith.” In very much the same vein, Owen can indicate that “the inbred principles of natural light, or first necessary dictates of our intellectual, rational nature” provide a “rule unto our apprehension” of all things, even of divine revelation. Witsius can even declare that the faint glimmerings of the natural light provide a “foundation” on which the gospel can build: “for as grace supposes nature, which it perfects; so the truths revealed in the gospel, have for their foundation those made known by the light of nature.” Although Witsius here addresses calling and, specifically, the character of the natural knowledge that seems to call human beings to God, only to leave them without excuse in their sins, he also, like Turretin and Owen, raises the issue of the positive relationship of natural reason and the truths it knows to revelation and supernatural theology.
Despite Turretin’s intimation that one can “build” on natural revelation and Witsius’ use of the term “foundation” it is clear that they do not intend to undermine their prior assumption that “supernatural theology” is “strictly called revealed, because its first principle is divine revelation strictly understood, and [because] it is grounded on the word, not on creatures.” Rather Turretin’s intention is to elaborate his other claim that theology drawn on other forms of knowing “as a superior from inferiors” in the very specific sense that it “presupposes certain previously known things upon which it builds revelation.” Thus, despite the fact that reason and faith “are of different classes, the former natural, the latter supernatural,” they are not “opposed”: rather “reason is perfected by faith and faith supposes reason.” Not corrupted reason, but reason “as sound and in the abstract” concurs with and supports theology. Indeed, as Owen indicates, reason can discern when theological claims are illegitimate—as in the case of the utterly irrational Roman Catholic doctrine of transubstantiation. This is not a mystery from beyond reason, like the Trinity, but a teaching that is contrary to reason—as Turretin would say, a doctrine that proposes not incomprehensible but incompossible things.137
Muller, R. A. (2003). Post-Reformation reformed dogmatics: The rise and development of reformed orthodoxy; volume 1: Prolegomena to theology (2nd ed.) (297–302). Grand Rapids, MI: Baker Academic.
