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God, Natural Knowledge of


I. The logical, internal structure of the human knowledge of God. - II. The teachings of the Magisterium of the Catholic Church: an historical outlook and recent documents. - III. The characters of a reason capax fidei and its perception of the Logos.


Despite of its long-lasting theological tradition and its deep-rooting into the very birth of philosophy, the theme of the natural knowledge of God has always been the subject of critical debate. Starting from the Modern Age, the different theological perspectives on this subject were mainly due to different understandings of the dynamic between faith and reason. The classical Lutheran position, especially with Karl Barth, that denies any access to God by reason alone, looks quite different from the Catholic view, generally more open to the possibility of knowing God through some philosophical paths. Moreover, the theoretical approach to any knowledge of God by faith and/or by reason is highly influenced by the meaning and by the content we associate with the two words “faith” and “reason”. The possibility of a natural knowledge of God is an important issue not only for philosophers and theologians, but, to a certain extent, also for scientists, who could be interested in a notion of God as foundation and ultimate cause of all physical reality. The way in which we understand a natural knowledge of God leads to the possibility of a “natural theology,” influencing philosophical and theological epistemology, but also soteriology, addressing the question of which salvation may be associated with such a knowledge. Without discussing any specific “ways” of coming to the knowledge of God, the first section of this article offers an overview of the subject focusing on the role there played by faith and reason. The second section recalls the view provided by the Magisterium of the Catholic Church, while the third section will discuss which perception of a Logos can be grasped from the study of physical reality. (On the natural knowledge of God, see, among others, Miller, 1996; Sokolowski, 1995, Haldane, 2000; Manning, 2013).

I. The logical, internal structure, of the human knowledge of God

It is important to distinguish and explain the meaning of two different approaches, that of a “natural knowledge of God” and that of a “revelation of God in creation.” The two approaches are clearly linked to each other, but they are also distinct. The former is a philosophical journey that leads to an image of the “Absolute” that is dependent on the specific method that was chosen (metaphysical, phenomenological, cosmological, anthropological, etc.); the latter one is a theological issue concerning theology of Revelation. In the natural knowledge of God, the human being, using his natural reason, tries to arrive at a notion of God; instead, when we refer to the revelation of God in creation, it is God who reveals himself to someone (and not to something), as subject of an act directed to the human person. Here, faith is the human response to the revealing God, hearing a Word that God pronounces through creation and/or through history.

The possible understanding of the statement “natural knowledge of God” is influenced by the broad semantic of the adjective “natural.” This adjective includes both “critical” philosophy, which reaches its conclusions by means of natural reason alone (that is, without the help of any supernatural revelation) and “spontaneous” philosophy (that is, common sense experience starting from our knowledge of nature), along with its existential, aesthetic and religious implications. When the theologian studies the data contained in Sacred Scripture in order to examine the existence of such a knowledge, this semantic range must be taken into account, addressing the question of what type of natural knowledge of God Sacred Scripture is referring to. An improper discernment can lead a hasty reader to feel that he has found biblical Revelation supporting the validity of some specific philosophical and rational paths at the expense of others, forgetting that the Bible can speak of different possible paths of accessing God depending on the different contexts and literary genres. The theologian should also examine whether a specific passage of the Bible refers to the idea of God’s revelation in created nature (cf. Jb cc. 38-39; Ps 8, 18, 103; Sir cc. 42-43), or, rather to the idea of our knowledge of Him through nature (cf. Ws 13:1-9; Rom 1:18-20, 28; Rom 2:14-16; Acts 14:15-18 and 17:22-34).

Any philosophical journey that intends to achieve a “natural knowledge of God” is unable to reason in a totally autonomous way. Neither the specific route, nor the linguistic or conceptual horizon chosen, can develop in a way completely independent from any religious dimension of God, including some elements derived from God’s revelation. This state of affairs increases the complexity of the problem. For instance, when speaking of God, the philosopher of language needs some elements taken from anthropology, the metaphysical philosopher needs some concepts derived from common sense, the historian of religions needs notions drawn from the phenomenology of religion, etc. In general, when we speak of a “natural knowledge of God” the incompleteness of a formal philosophical rationality faces two main problems.

The first of them, as appropriately highlighted by various authors, is that all natural knowledge of God, or more precisely all natural knowledge of the Absolute, for hermeneutical reasons implies a somewhat previous notion of God available to the knower: a notion or a concept of God is borrowed primarily from the world of religious experience. According to Etienne Gilson, the idea of God fills and enthrones the aspirations of the metaphysician, but the idea of God does not originate from him (cf. Gilson, 1949, 1955). In addition, religious experience is particularly connected to a spontaneous philosophical experience (common sense experience), thereby allowing an inevitable but also fruitful exchange of knowledge between these two fields, which offer to each other a support of intelligibility. Thomas Aquinas was very aware of this situation when he wrote his famous Five Ways for the existence of God: in particular when he used the expression: “[…] and everyone understands and call this God” (Summa theologiae, I, q. 2, a. 3). It should also be noted that only if the concept of God comes from the existential and religious world of the subject, then it is appropriate to recognize God or the divine as a result of a kind of revelation, calling it “God’s revelation through creation/nature”. This previous notion of God may be present in the subject in a non-thematic transcendental way, or also perceived categorically, when the subject observes nature, listens to his or her conscience, or reflects on the meaning of existence.

A second basic reason why a completely autonomous rational-philosophical journey towards the Absolute seems impracticable is that there is a “principle of creation” that precedes every philosophical question, and from which the same inquiring subject depends — at least, in so far as he or she honestly recognizes that one is not able to solve the “problem of contingency” in a self-referential way, and recognizes the need for a causal foundation of Being. In philosophical terms, such a principle of creation simply means that human reason, in order to prevent itself from being ideological, must remain open to recognizing the existence of an “ontological foundation” able to solve the unsolved ontological questions, that is, it must remain open to be unraveled as a created reason.

It is easy to see that we are facing an issue having different gnoseological and hermeneutic aspects, and whose vocabulary, often unconsciously, is not always used consistently. When the internal, subtle, philosophical articulation within the natural knowledge of God has been underestimated, this has historically given rise to misunderstandings, oversimplifications and inconsistencies. As a result there were significant repercussions on the understanding of the relationship between faith and reason; for example, many have thought that when the philosophical and religious orders are identified as separate orders, this should lead to denying the feasibility of “philosophical proofs” for God’s existence. In reality these proofs can always be used, insofar as there is a rigorous philosophical way to connect the logical-epistemological and the anthropological-existential fields, and as long we avoid misunderstandings on the meaning of the word “God,” and the attributes we associate with such a notion. In those intellectual contexts which emphasize that religion is much more than philosophy, that God must be a Personal being, and that we can address to Him only by “prayer,” it is more correct to speak of “philosophical proofs of the existence of an Absolute,” of a “Necessary Being,” etc., instead of “philosophical proofs for God’s existence.”

Natural knowledge of God is compatible with two different but interrelated perspectives, two different conceptual ways of seeing the same thing within the dynamic of the relationship between faith and reason. According to the first perspective, the natural knowledge of God may be considered as belonging to the field of faith: the notion of God is derived from religious experience as a form of belief or faith —supernatural faith when the notion of God is derived from the religious experience associated with the Judeo-Christian revelation. In this case, the natural knowledge of God is a “descending path” from faith to reason, a path that justifies the reasonableness and universality of the faith in the One God, since we can link this supernatural or religious knowledge of Who God is with other universal and all-comprehensive concepts belonging to natural reason. In so doing, God known by faith can satisfy the thirst of reason in search of a foundation for the existence of the cosmos, and in search of a meaning for human life. From another perspective, the knowledge of God may be conceived as a journey of the intellect that is not enlightened by faith; in this case, such an “ascending path” can solely be accrued by the effort of philosophical thought, reaching an “image of the Absolute” that will be defined by philosophical rationality only, not by revelation. The attributes of the Absolute (necessary being, beginning and end of all things, an Intelligence responsible for order and rationality in the cosmos, the supreme Good, etc.) will be different among each other, depending on the specific philosophical method or domain here used. Thus, the premises are here settled, that once the subject will have access to a religious-existential notion of God, he or she can also reach the conclusion that “[...] and this everyone understands and calls God.”

The interrelationship between these two perspectives, however, becomes clear when we move from a purely theoretical knowledge to the religious experience generated by faith. An intelligible, communicable faith in God must rely on an image of God that can be known by philosophical reason; on the other hand, a rational path that does not wish to remain a pure abstract exercise but rather wants to engage with human knowledge and experience, should connect with the subject’s religious world: for instance, remaining open to recognize the mystery of existence. In more general terms, the similarity between these two perspectives is explained by Thomas Aquinas using the metaphor of a “double movement:” the ascending path of a philosophical /rational knowledge of God, and the descending path of a divine revelation, provided that they are not two independent ways, but different directions along the same and one road (cf. Summa contra Gentiles, IV, c. 1 and II, c. 4).

The debate on the natural knowledge of God offers theology a number of opportunities, but it also raises some open questions. A first opportunity comes in the field of inter-religious dialogue, since the search for God through nature plays here a key role. Secondly, the re-evaluation of the natural knowledge of God as a “preamble of faith,” both from an anthropological-religious and a philosophical-rational perspective, would strengthen any discourse about the revealed God, in a cultural climate where faith is challenged by a widespread relativism and religious indifference. Finally, a sacramental understanding of the cosmos becomes possible,  since it reflects the Logos through whom all things were made. A Christ-centered view of creation is then highlighted, in which nature is well apt to receive the gift of the Incarnation, having some implicit links to a cosmic dimension of Christian salvation.

Among the questions addressed to theologians there is how to value and explain the classical doctrine about the sufficiency of a natural knowledge of God and God’s revelation in nature, to let human beings reach a supernatural salvation. According to this doctrine, in the absence of a historical revelation, and thus in absence of a written Word, a honest reason (Lat. recta ratio) can recognize the true God and His law written on the human heart. This implies going more in depth in  the relationships among philosophy, religion and revelation; especially asking what kind of “faith” is necessary for this way of salvation, and to what extent is this faith a true personal response to a revealing God, or rather a mere belief or a simple feeling of astonishment before a manifestation of the divine (cf. Fides et ratio, nn. 31-33; Dominus Iesus, n. 7). On the other hand, if we admit that a natural knowledge of God is necessary to understand what Revelation says when speaking of God, theology should also clarify whether such a knowledge may derive only from religious experience and common sense, or, on the contrary, if some other kind of rational/theoretical philosophical knowledge is also required. And finally, how do original and actual sins affect these forms of knowledge, both on a personal level, and on historical and social dimensions?

The theology of the 20th century provided different answers to these questions, depending on the different emphasis given to either faith or reason, and depending on which pole theologians preferred to start with, namely God’s revelation or the human search for Him. These answers also brought about some pre-conceptions that influenced the understanding of the Church’s Magisterium teachings on this subject, that is, the right hermeneutics to read its official statements. On the other hand, even the declarations of the Magisterium and the vocabulary there used were inevitably affected by the philosophical-theological context in which those declaration were written. However, despite of all these hermeneutical limitations, some homogeneous guidelines can be easily outlined. Let us read some of the essential official statements on the subject.

II. The teachings of the Magisterium of the Catholic Church: an historical outlook and recent documents

In many of its pages, the Encyclical Fides et ratio affirms that human reason is capable of recognizing the existence of an Absolute, it is able to rest on a stable truth, which is attainable beyond observable phenomena, the flow of language, and the stream of history and its diverse interpretations. What the Encyclical states is evaluated alongside the history of 20th century philosophy, especially its critical approach to the question of truth, in both its metaphysical and existential aspects (cf. Fides et ratio, nn. 24, 34, 36, 53, 67, 81, 83, etc.). In so doing, the Encyclical summarizes and re-affirms a conviction that, despite some hesitations and the co-existence of different philosophical perspectives, has been present both in theological reflections and in the Church’s faith since the first centuries of the Christian era (cf. Morerod, 1999).

If we leave aside the declaration of Pope Clement XI against the Jansenist Quesnel (cf. DH 2441), the first statements of the Magisterium of the Catholic Church concerning the possibility of a natural knowledge of God’s existence trace back to the theses attributed in 1844 to Louis-Eugène Bautain by the Holy Congregations of Bishops and to those attributed in 1855 to Augustin Bonnetty by the Congregation of the Holy Office. They were asked to “never teach that, with the sole use of pure human reason, without the help of divine revelation, we cannot prove God’s existence,” (DH 2765); in other words, it had to be affirmed that “human reason can prove with certainty (cum certitudine probari potest) the existence of God.” (cf. DH 2812 and DH 2751). Some years later the First Vatican Council (1870) addressed this subject in a paragraph of the constitution Dei Filius, in which we read: “God, the beginning and end of all things, can be known with certainty (certo cognosci posse) by the natural light of human reason from created things.” (Dei Filius, c. 2; DH 3004). This statement will be then taken literally by the Second Vatican Council (1965) (cf. Dei Verbum, n. 6), and will also be commented by Fides et ratio (cf. n. 53). In teaching thus, the First Vatican Council wanted to give effective answers to both rationalism and fideism. It addressed the anti-religious approach of rationalists affirming that, even without the help of divine revelation, it was possible to reach a philosophical knowledge of God. Also, it addressed fideists, who were underestimating the role of reason, as the Council affirms that access to the truth is not exclusive to faith. Due to the conciseness of the Dei Filius’ statement, religious and philosophical dimensions seem undistinguishable from each other, though the sentence “God, the beginning and end of all things, [...]” seems to contain both of them, as “God” is a name invoked by religious man, while “beginning and end of all things” may refer to a philosophical conclusion; however, in a subsequent canon, this articulation is less clear and the statement more theological, as we read “the one true God, our Creator and Lord” (DH 3026). The Council is also concerned to distinguish “divine faith,” from the natural knowledge of God and from the knowledge of the moral natural law, intending to protect the authority of God as the formal reason of our belief in the revealed truths (cf. DH 3032).

The Encyclical letter Pascendi dominici gregis (1907), written as a criticism of agnosticism, emphasizes the capacity of human reason to go beyond the appearance of phenomena, refusing the view that “reason is not able to reach God, nor to understand God’s existence, even by means of observable things.” (DH 3475). The Encyclical also adds that this agnostic view of reason would imply incorrectly that God is not an object of historical knowledge (that is, as if the effects of God’s existence would not possess any historical dimension). Another document written a few years later, Sacrorum Antistitum (1910), contains the same doctrine, while using a more metaphysical language, when declaring that: “God, the beginning and end of all things, can be known, and therefore also shown (demonstrari etiam posse), as the cause from its effects (tamquam causam per effectus) with the natural light of reason, through the things that are made, through the visible works of creation.”(DH 3538). It is interesting to note that, a few decades before, the Fathers of the First Vatican Council, as the result of a debate, preferred to use the term cognosci rather than the term demonstrari (cf. J.D. MANSI, Sacrorum Conciliorum Nova et Amplissima Collectio, 51 [1961], coll. 276 and 296). A few years after Sacrorum Antistitum, the 24 Theses approbatae philosophiae thomisticae (1914) were published in reaction to modernism and agnosticism, recommending the use of a specific philosophical language. One of these theses stated: “We do not perceive with an immediate intuition that God exists. We can prove only a posteriori, and not a priori, that God exists, only by observing the things that have been made, from the effect to the cause.” Here the thesis summarizes the five different “causes” which correspond to the “five ways” to God taught by Thomas Aquinas (DH 3622). All these declarations, including that of Vatican I Council, are aware of the specific and limited ambit of a natural knowledge of God reached following some particular philosophical paths. Indeed, they make precise the formal perspective under which such a rational conclusion, namely the existence of God, can be achieved: as the beginning and the end of all things, as the knowledge of a cause starting from its effects, or other analogous expressions.

The content of the Encyclical Humani Generis (1950) by Pope Pius XII is mainly targeted at the controversy concerning the Nouvelle théologie. The expressions there used to underline the strength of human reason and the eternal validity of the “unshakable principles of metaphysics,” are highly effective. “Everyone knows —the Encyclical says— how much the Church appreciates the value of human reason, which has the task of proving with certainty (certo demonstrare) the existence of one personal God and also verifying (invicte comprobare) the very foundations of the Christian faith by means of divine signs” (DH 3892). At the same time, the document provides an extensive analysis of the causes which determine a decreasing, or even a failure, in our capacity of recognizing the value of reason: “Even if human reason, absolutely speaking, with its strength can actually embrace the true knowledge of a unique and personal God who sustains and governs the world by His providence, and also the knowledge of the natural law engraved in our hearts by the Creator, there are still some obstacles that prevent our reason from using effectively its natural power.” (DH 3875). Two main obstacles are here mentioned: firstly the lack of philosophical formation, which often is not given nor sought, yet necessary to approach this kind of issue; secondly, subjective and existential elements affect all knowledge concerning the existence of God and the recognition of a moral law, being two subject-matters having relevant consequences for our lives.

The Second Vatican Council had no special interest in developing philosophical issues, as its main theological view was to focus on the history of salvation and the meaning it has for contemporary men and women, less versed in metaphysics and more sensitive to anthropological and existential approaches. From this point of view, it could be said that the Second Vatican Council, especially the constitution Gaudium et Spes, conveys as a whole a doctrine on the “reasonableness of the existence of God”, more than a philosophical doctrine on such an existence. This reasonableness is grounded upon a convergence between anthropology and Christology: human ultimate questions about the meaning of life find a complete and credible answer in Jesus Christ; in him, God becomes man and takes upon himself all the dimensions of human life. However, as mentioned above, Vatican Council I’s  teaching about the natural knowledge of God is also present in Vatican II (cf. Dei Verbum, n. 6), including Aquinas’ doctrine about the moral necessity of  divine revelation of some truths that, in principle, reason could achieve by itself —a revelation necessary due to the historical situation of human beings, whose reason is limited and weakened by sin. While Dei Filius chose to address the theme of the natural knowledge of God just at the beginning of its chapter n. 2 entitled De Revelatione (cf. DH 3004-3005), the Second Vatican Council starts its reflection on Revelation presenting the historical revelation of God in the Old and the New Testaments; however, the document soon introduces a brief reference to the revelation of God through creation (although the term revelation is not used here), stating that “God, who creates and preserves all things by his Word, provides to men a testimony of His existence, through all things that He created.” (cf. Dei Verbum, n. 3). The word testimonium, here employed, appears many times in the documents of the Second Vatican Council, and represents a privileged category for the understanding of Revelation, for its credibility and transmission. As expected, the two perspectives, namely the natural knowledge of God and God’s revelation, while being mutually distinguishable, are in fact connected to each other: natural knowledge of God is like the effect of the revelation of God in nature: in order to acquire a knowledge of God from created things, we need a first, radical condition, that things were created: that is, we need before an opening and originating manifestation/revelation of the Word of God.

Recently, the Church's Magisterium has shown a renewed interest in philosophy. In particular, the natural knowledge of God is associated with the quest for truth, a search that cannot remain frustrated, because it is adequate to the capacities of human reason. Even before Fides et ratio, such a teaching was explicitly present in Donum veritatis (1990), a document published by the Congregation for the Doctrine of the Faith and addressed mainly to theologians. In critical dialogue with philosophical relativism and agnosticism, the documents affirms: “Despite the assertions of many philosophical currents, but in conformity with a correct way of thinking which finds confirmation in Sacred Scripture, human reason’s ability to attain truth must be recognized as well as its metaphysical capacity to come to a knowledge of God from creation.” (Donum veritatis, n. 10).

The role of philosophy is especially developed, as is known, in Fides et ratio (1998). The Encyclical is aimed at establishing the question of truth at the center of philosophy once again, as its proper object, and therefore the question of God is declared again as an object adequate to reason. The large extension of this document and the many issues it raises, prevent us from giving here an account of its contents; we then limit ourselves to summarizing those points which seem to be more relevant for the subject-matter of the present article (for a comment to the document, see: “A Symposium on Pope John Paul II’s Fides et Ratio”, 1999; Smith, 2001; Hemming and Parsons, 2002; McEnvoy, 2002; Ruel Foster and Koterski, 2003; Livi and Lorizio, 2005). One of the passages that more clearly concerns our matter is undoubtedly Fides et ratio n. 67, where it is said that there are “truths which are naturally, and thus philosophically, knowable; and an acceptance of God's Revelation necessarily presupposes knowledge of these truths.” Among these truths, a “natural knowledge of God” is mentioned explicitly. Elsewhere, in the same document, we read expressions like these: there is “a path which the human being may choose to take, a path which begins with reason’s capacity to rise beyond what is contingent and set out towards the infinite” (n. 24); consequently, “a philosophy denying the possibility of an ultimate and overarching meaning would be not only ill-adapted to its task, but false” (n. 81); there is “the need for a philosophy of genuinely metaphysical range, capable, that is, of transcending empirical data in order to attain something absolute, ultimate and foundational in its search for truth” (n. 83); and, finally, we face a great and urgent challenge “to move from phenomenon to foundation.” (n. 83). The teaching of some truths of reason, including the natural knowledge of God, is necessary to understand the content of divine revelation (cf. nn. 36 and 67), although such a knowledge can also be accessed using intellectual paths different from those provided by philosophical-theoretical argumentations. These alternative paths are implicitly referred to by the document when it speaks of human religiosity and of the treasures of wisdom and culture espoused by many people, for whom the search for God and for the answers to the great questions of human life constitute a central object of their reflection and of their traditions of knowledge. The positive value attached to such religious experiences is ultimately based on the fact that God makes Himself known through the created world, a manifestation that is here explicitly called “revelation” (cf. n. 19), a word that the Vatican Councils I and II did not use in this context. The Encyclical speaks of “reason” within a realist framework, though aware of the changing historical circumstances, and also conscious of the many difficulties man encounters in the quest for truth, The power of reason is outlined according to its limitations, suggesting that it is precisely Revelation which can solve the paradoxes of reason, disclosing to us the deeper meaning of all things (cf. nn. 23 and 76).

The Encyclical letter Fides et ratio by John Paul II provides useful insights to tackle the questions we mentioned at the end of the previous section, that is, the necessary articulation between religion and philosophy in knowing God’s existence. The document contains valuable elements to clarify the relationships among Revelation, philosophy and religion, since they all are called to speak of God, each one according to its specific perspective. The document does not intend to resolve in an exhaustive way the complexity of such relationships, but it is aware that they all work and deserve to be decoded. While the majority of authors commenting on this Encyclical have underlined the double circularity between faith and reason, or between theology and philosophy, it is the triple circularity among Revelation, philosophy and religion, which provides the best intellectual context to correctly address the issue of the knowledge of God.

Until a few years ago, one of the main points of theological debate that influenced the hermeneutics of these magisterial documents concerns the issue of whether a natural knowledge of God is possible given the historical condition of man. As widely affirmed by the theological and ecclesial tradition, such knowledge is greatly affected by the moral health of the subject and by the negative effects that original sin, as well as sin in general, produced for the  human intellect. Even the Biblical pages on which the doctrine of the natural knowledge of God is based, present a kind of gray area between reasonable knowledge and culpable ignorance, because of the consequence of sin in human history (cf. Ws 13:1; Rom 1:21; Acts 17:27). Humility, justice and righteousness are therefore necessary to understand the presence and work of God in the world. Starting from the First Vatican Council, the Magisterium of the Church used expressions that referred to a “capability” understood as an abstract (impersonal) exercise of rational philosophy (cognosci posse). In addition, from the First Vatican Council to Fides et ratio, this teaching has been reaffirmed by means of the Thomistic doctrine concerning the “moral necessity” of Revelation; it is thanks to Revelation, indeed, that “all human beings can, in the present condition of the human race, know easily, with absolute certainty, and no errors, what is not inaccessible to reason within divine things.” (Summa theologiae, I, q. 1, a. 1). For this reason, the perspective chosen by Fides et ratio is very interesting and something new. In fact, the document frequently addresses historical aspects of human wisdom, along with its religious and philosophical dimensions, mentioning authors of different religions and cultural areas. A careful reading of these pages seems to indicate that we do not deal with merely a possibility, but indeed with a capability that has been put into act by human reason, in different epochs and different geographical places. The Encyclical speaks of this knowledge of God as a “desire”, but one that “philosophy has articulated with its specific tools and scholarly methods.” (cf. n. 24).

It should be said that, beyond the theological discussion that accompanied the hermeneutics of the Catholic Magisterium, in these teachings we are certainly dealing with a “minimum content,” which must be accepted for certain: the notion of God, without a doubt, is a notion intelligible to man. When Revelation tries to connect the Biblical image of the God of Israel (Lord and Savior of his people) with the concept of a Creator (cause of everything that exists), it speaks of a concept familiar to reason, a notion that intelligence can grasp with its own powers. On the other hand, if we go beyond this “minimum content” and maintain that human reason, despite its weakening due to sin, has historically known a route that leads to the existence of an Absolute starting from created things, this is not to say that we have a comprehensive and accomplished knowledge of the nature of God, without any help from Revelation. We only intend to say that reason can have an access to an unconditioned Absolute, knowable as the beginning and end of all things, causal foundation of reality; an Absolute also knowable, on a religious and existential level, as the response to the quest for meaning of human self-transcendence and to the opening of human freedom to the infinity.

Within the dynamics of the relationship between faith and reason, it is clear that any philosophical-rational argument which infers the existence of God would not cause, by itself, faith in God. It would only prepare the subject to recognize as reasonable the announcement of His revelation in history and to accept the gift of faith. The philosophical-rational analysis of a natural knowledge of God leads the subject to recognize the opportunity of a personal commitment for truth, the meaningfulness of  a humble approach to the mystery of Being. Only Revelation, however, will disclose that the true sense of this responsibility for the truth is the choice for a Person, the recognition of a calling, of an invitation to a communion of life. If we ask the documents of the Catholic Magisterium whether a natural knowledge of God is necessary in order to understand Whom biblical Revelation is speaking about when it speaks of God, the answer is affirmative. We back this conclusion on the tenor and character of many statements used, and on the choice the two Vatican I and II Councils made of speaking of a natural knowledge of God in the context of the doctrine of Revelation. Especially in light of the content of Fides et ratio, a correct hermeneutics of the teachings of the Magisterium on this issue shows that we are not dealing with a theoretical knowledge only, but also with ordinary knowledge and common sense; and that, in any case, the resulting image of the Absolute depends on the specific rational route chosen.

In summary, when examining the Catholic Magisterium on the natural knowledge of God, we see the rich connection by which Revelation, philosophy and religion are intertwined and mutually involved, and how such a relationship proves both the meaningfulness of the questions raised by reason, and the intelligibility of the answers received by faith.

III. The characters of a reason capax fidei and its perception of the Logos

If no other elements are provided, a first analysis of the dynamic between faith and reason concerning natural knowledge of God leads us to conclude that faith, probably, has no specific role for such knowledge. However, this conclusion corresponds to a certain understanding of the word “faith” (cf. DH 3032), that is, as a response to a historical categorical revelation, and also a specific conception of the term “reason”, understood as the exercise of a philosophical rationality independent of any notion of revelation. This understanding is acceptable, but it must be declared beforehand, especially when we want to interpret the Magisterial documents or texts written by other authors. If, on the contrary, we accept the idea that the autonomy of human reason is not absolute, and that God’s revelation in history includes a revelation of God in creation, then it is possible to consider a dynamic between faith and reason in the natural knowledge of God. This was partly noted at the beginning of Section I, when we observed that no philosophical journey that intends to access a “natural knowledge of God” can develop its arguments in a completely independent and self-referential way, if it wants to come to a conclusion on the existence of God rather than accessing only philosophical attributes of Being. This implies the need to access religious-existential aspects where the notion of faith, or at least of belief, is necessarily playing a role. In addition, in Section II, we recognized that the term “natural knowledge of God” has a specific meaning also when this is seen as a journey of faith towards reason, in order to assure the universality of a concept of God known by revelation; even if the rational knowledge of a philosophical Absolute possesses a logical priority with respect to a religious-existential knowledge of the notion of God, this does not imply that, in the believer, this knowledge has a chronological priority, allowing faith to look for the intelligibility of reason (quaerens intellectum).

A reason capable of understanding the existence of an Absolute, the existence of a necessary and transcendent foundation, and that recognizes this Absolute as its proper object, does not operate within a theological-divine faith; nevertheless, it is a reason capax fidei, capable of faith. Such a reason understands itself not in a self-referential or self-sufficient way; it can encounter faith, since it is a non-ideological reason, a reason without hybris, aware of its ontological contingency and of its finite horizon. These are, in fact, the features Catholic theology has often referred to as recta ratio (cf. Fides et ratio n. 4, 41, 50; DH 2765; Gaudium et spes, 63). It is a reason, we here define, as “open to being disclosed as created reason”. It is a reason that begins its journey from the realism of what surrounds us and that has the humility to let the otherness of reality speak. It is a reason placed in front of a natural revelation of God, which always and in any case precedes it, even if the subject could not perceive it immediately as such. It is, however, a free reason, as shown by the possibility of a refusal to remain open towards a “principle of creation.” A natural knowledge of God is conceptually placed between the two forms of revelation, the natural and the historical-supernatural revelation, and, as for other “preambles of faith”, can be given only in a reason prepared to receive the reality as datum, as something given, and thus created. Its willingness to be disclosed as created puts it in a logical dependency by a preceding revelation (natural revelation) which occurred, actually; it represents, for reason, the necessary condition for hearing and understanding Revelation (taken as a whole, natural and historical), when this speaks of God.

A coherent study of the dynamic between faith and reason, however, should also analyze the nature of the act by which one recognizes reality as a rational, ordered datum, he or she decides to listen to reality as to a dialogical otherness, and let reason operate in a non self-referential and non-ideological way. To perform this act, is some form of faith necessary? For instance, a faith in a divine natural revelation? Thus it is important to clarify this dynamic, avoiding a sort of petitio principii, bypassing the dangerous circularity of a reason that, in order to be capable of faith, should have previously embraced some kind of faith. In order to answer this question, in our opinion, we must distinguish in the nature of the act mentioned before, two particular moments having different degrees of anthropological meaning.

The “first moment” of the act of reason which acknowledges reality as datum (given) and allows reality to speak is when the subject recognizes the contingency and the limit of his or her creaturely condition, and also the impossibility of human words to explain reality as a whole. This does not constitute nor explicitly imply any answer to a revelation of God within nature. This recognition is the proper object of a rationality capable of realizing the existence of an unconditioned and necessary Absolute, as a reasonable answer to one’s personal contingency. The humility required for doing this is simply called “objectivity” and “realism.” In this first stage, reality is grasped as a given otherness, that is, something not established by the subject, as a source of rationality seeking a foundation. We can summarize all these perceptions saying that the subject discerns a Logos ut ratio. Some authors have seen in such recognition an option towards reality, an assent to Being, a sort of “faith” in the rationality of nature. This is the case of the “scientific faith” as theorized, for example, by Albert Einstein, Max Planck or other realist scientists; and it is the case of faith in the first principles of scientific knowledge which cannot be proved by scientific method, but are drawn from common sense, as indicated by Michael Polanyi or Thomas Torrance. It is only a matter of preference: we can enlarge the semantics of the term “faith,” qualifying as an act of faith both the subject’s assent to reality, and the rejection of any ideological self-reference, or qualify this act nothing more than a “reasonable” choice. We are certainly not speaking of theological faith, but of a free act of the subject —to emphasize the role of this freedom we may recall Polanyi’s expression of knowledge as commitment— an act that exceeds the standards of formal and syllogistic knowledge, and that therefore includes a kind of belief based upon a subject’s personal and existential context.

The “second moment” is represented by the response given by the subject to a revelation of God through the language of creation. In this case, the subject not only grasps in reality the image of a Logos ut ratio, but also acknowledges reality as the effect of a Logos ut verbum. The world is perceived as a given, dialogical and meaningful otherness (cf. Tanzella-Nitti, 2005). The degree of the subject’s commitment is quite profound, that is, “responsible” in front of Someone (from the Lat. respondeo): the amazement before Nature causes at first a feeling of awe and reverence which leads to a feeling of adoration, inquiring as to its Author (cf. Desmond, 2000; Cantore, 1977). Thus, in this second moment, the act by which the Absolute is acknowledged as object of a personal relationship, and reality is recognized as something given by a Donor, that is a created reality, can be now classified as a religious act and not as a mere philosophicus act (cf. Tanzella-Nitti, 2000). Only this second moment of the act can be qualified as an act of faith, because it implies the subject’s trust and self-donation. As a religious act, this act of faith implies not only the admission of one’s creaturely being and the acknowledgment of one’s non self-sufficiency, but also openness to the mystery of the Absolute and, above all, the free expectation of what this mystery may reveal. The proper object of this act is no longer God as knowable in a natural/rational approach, but the Author of the world as a Subject to whom we address our gratitude and expectations. The theological understanding of this religious act easily follows the known Catholic doctrine about the faith and salvation of those who do not come into direct contact with the historical-supernatural revelation, but have knowledge of God only through the created world and the consciousness of a natural law written in their hearts (cf. Lumen gentium, n. 16).

The theological question previously highlighted, concerning the nature of the act by which the human being recognizes reality as datum (Logos ut ratio) thanks to the exercise of an open and non-ideological rationality, can be answered by saying that this humble approach of reason does not imply any theological faith, and therefore there is no petitio principii in understanding such a humble reason as capax fidei. However, as it ends by recognizing something datum as given, and then created, it is an act in which the grace of God is mysteriously present (cf. Lumen gentium, n. 16; Gaudium et spes, n. 22). It is reasonable to think so, because without the aid of God’s grace, the natural powers of reason, wounded by sin, could easily fall into the temptation to transform the experience of limit and finitude into nihilism and nonsense, rather than remaining open to acknowledge a principle of creation. This dynamic can be further clarified suggesting that natural revelation of God through creation should be considered according to two different approaches. According to an objective perspective, that here we could call ex parte Creatoris, God’s revelation in nature coincides with what we referred to previously as “principle of creation,” or “principle of revelation.” In this sense, this precedes any philosophy of God (spontaneous or rationally argumentative), and therefore also any natural knowledge of God, explaining why, when we talk about reason, we must always speak of a created reason. According to a second perspective, that is, ex parte subiecti, a natural revelation of God is distinguishable from a mere principle of revelation: in order to have a real revelation of God to a personal subject, it is necessary that the subject enacts  his or her responsible answer. For a word to be revealed (Ger. Wort) it is not enough to hear it or reflect upon it, but also to exercise a responsibility (Ger. Verantwortung) and provide a free answer (Ger. Antwort).

Summing up, the philosophical approach here proposed leads us to a simple but important result: the natural knowledge of God is a too difficult, sensitive and complex issue, so as to be described without contextualizing it in a conceptual and terminological framework. If we discuss its relevance for reason and faith, without a prior clarification on the hermeneutics there involved, for the philosopher as well as for the theologian, the risks of  misunderstandings is highly probable. We think that this situation is reflected, or even it has a proof, in the sometimes contradictory hermeneutics many authors gave of Blaise Pascal’s thought about the rational knowledge of God. Different commentators gave very different and sometimes opposite views, given the fragmentary nature of Pascal’s work and the difficulty of reconstructing with sufficient accuracy the context of his Pensées, when the different fragments are not rightly contextualized. Actually, something analogous happens when different authors do not sufficiently specify their philosophical context and the interlocutors they address (e.g., the epistemological and anthropological framework used to carry out their reflections); this results in a fragmentation, leading to somewhat conflicting views, or to contrasting hermeneutics offered for the texts of the Catholic Magisterium. This is almost an echo of Pascal’s provocative statement: “It is incomprehensible that God should exist, and it is incomprehensible that He should not exist.” (Pascal, Pensées, n. 230).

Documents of the Catholic Church related to the subject: 

Abbreviations and complete titles of the documents

DH 2751, 2765, 2812; Vatican Council I, DH 3001-3004; DH 3538, 3622; Humani generis, DH 3875-3876; Dei Verbum, 3, 6; Lumen gentium, n. 16; Donum veritatis, 10; Fides et Ratio, 19, 23, 31, 33, 53, 67, 76.


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