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I. Introduction - II. The Concept of Truth in the History of Thought. 1. Truth as Correspondence between Thought and Reality. 2. Truth as Display, Openness, Evidence, Direct Contact, Discovery. 3. The Concept of Truth as Revelation. 4. Truth as Coherence . 5. Truth as Conformity to a Rule or to a Person . 6. Truth as Inter-Subjective Consensus. 7. Truth as Utility and Efficiency. - III. Further Reflections on the Concept of Truth. - IV. Aspects of the Concept of Truth in the Philosophy of the 20th Century: Jacques Maritain and Martin Heidegger. 1. Jacques Maritain's View. 2. The Problem of Truth according to Heidegger. - V. The Truth within Judaeo-Christian Revelation - VI. The Relation between Faith and Science - VII. Truth and Philosophical Realism.

I. Introduction

The central question for science, philosophy, and theology is truth. In each of these three great areas of human knowledge truth is incessantly sought for with diverse methods and along different roads, so representing their infinite duty. None of these sciences will ever reach the entirety of truth, but through them the human intellect hopes to draw progressively nearer to it. Scientists, philosophers, and theologians who share a realistic philosophical orientation, approach the problem united, since they recognize a common goal. Each is fully aware that there is a truth to search for, towards which one should draw near in a envisaged encounter that is difficult to reach, but in principle possible.

At the foundation of human knowledge there is the intuition that there is a profound intelligibility in the real world, in which the Logos expresses itself. Creation is the place for a great dialogue between the human and the divine intellects. Both the eternal mystery and wonder of the world lies in its intelligibility. There could not be science, philosophy, or theology without the assumption that it is possible to seize reality with our ideas, nor without stating, at some certain degree, the harmony and intelligibility of being. This intuitive matrix, which establishes the point of communication between the Christian faith, philosophy, and science, is both a postulate and the outcome of a long journey of research in which it was possible to reveal the existence of an agreement between knowledge and reality. This has caused us to question the link that lies between our knowledge and the cosmos. In the light of biblical Revelation, the possibility to make science or philosophy results from the fact that the cosmos is created, and also from the human condition of being image of God, imago Dei. Along the path of human intellectual history, we have come to understand that our knowledge of things cannot proceed a priori, but it must always be based on the real nature of the objects we consider. Our knowledge of God as well as that of a blade of grass, though linked in virtue of the universal concept of being, differ in that the objects that conform themselves to human knowledge are diverse. Within the postulate of the unity of truth, i.e. the axiomatic principle of the impossibility of siding with the doctrine of double or multiple truths, affinity exists, therefore, between theological, philosophical, and scientific research of intelligibility.

That does not imply, however, that the truths attained are all of equal level or reached by an univocal procedure. The encyclical Fides et ratio, while maintaining the unity of truth, admonishes that "faith and reason are like two wings on which the human spirit rises to the contemplation of truth" (n. 1), aware that reason has many ways of expressing itself.

Once science is reminded of its cognitive limits (it cannot know everything) and moral limits (not all that which is scientifically possible can be permitted), it is worthwile remembering the cognitive foundation (both of a philosophical and even "theological" nature) upon which science rests; namely, upon the idea that the whole is intelligible and meaningful.

II. The Concept of Truth in the History of Thought

If it is well founded that human happiness consists in the fruition of truth (as stated by many philosophers, including St. Augustine), practical knowledge of truth is of major importance for human life, as we are unsatisfied in attaining a merely epistemological conception of truth. Certainly, the development of modern science (from this period two emblematic dates stand out: 1543, the year of the publication of De Revolutionibus Orbium Caelestium by Copernicus, and 1687, when Philosophiae Naturalis Principia Mathematica by Newton appeared) has underlined the importance of epistemological truth, though without claiming any obligation to maintain it as the sole truth. Truth, in fact, has also an existential meaning: it is not only something that one knows, but also something that illuminates life and directs our free actions.

Since the concept of truth is liable to be defined in various ways, a reasonable approach to the subject is to present a historical and doctrinal perusal, which recalls some of the main acceptations of truth that have been advanced throughout history. We refer specifically to the concept of "theoretical" truth, rather than the practical (of actions and desires), or the esthetical truth. The fundamental concepts of truth presented in the history of thought are reducible to seven positions: a) truth as correspondence between thought and reality; b) truth as display, openness, evidence, direct contact, discovery; c) the concept of truth as a kind of revelation; d) truth as coherence; e) truth as conformity to a rule or to a person; f) truth as inter-subjective consensus; g) truth as utility and efficiency. The biblical idea of truth as faithfulness and stability (see below, V) could be added to these positions, an idea which one finds in an original manner in the Scriptures, though not opposed to truth as conformity.

1. Truth as Correspondence between Thought and Reality. Among the meanings listed above, that which has prevailed the longest is the present one. It is already existent at the beginnings of Greek thought and it is clearly expressed in Plato: "the true discourse is that which tell things as they are, the false is that which tells thing as they are not." (Cratylus 385b; cf. also Sophist, 262e). The theme had successively been taken up and suitably amplified by Aristotle particularly in Metaphysics: "It is true to say that being is, it is false to say that being is not." (IV, 1011b, 27-28; cf. also Categories, 4b, 8). These concepts of Greek thought were developed with few modifications by successive thought and became a landmark in Christian and Jewish philosophy and theology (for instance with Moses ben Maimon). Later Thomas Aquinas appealed to and made classic the well-known formula according to which declarative truth which is expressed in a judgment must be understood as a "correspondence between thought and reality" (adaequatio intellectus et rei: Summa Theologiae, I, q. 16, a . 2; cf. De Veritate, q. 1. a . 1). For Aristotle (cf. Metaphysics, VI, 1027b, 25f ) and for Aquinas (cf. Summa Theologiae, I, q. 16, a . 1) declarative truth (also called "apophantic," that is, showing itself) is in thought, that is, in the intellect which composes, correctly or falsely, a subject and predicate. However, the measure of truth is of double consideration. In the case of human knowledge, the measurer is the "real thing", i.e. the res, not the mind/intellect (cf. Metaphysics, IX, 1051b, 5). Vice versa, the divine intellect is Himself the measure of all things, from where the human intellect is always measured-except in the production of artificial things (cf. De Veritate, q. 1, a . 2). For Thomas Aquinas, the thing towards which the intellect must adapt itself is the res understood in the concept. Accepting the Aristotelian definition of declarative truth, Thomas, wonderfully brings to light both the ontological foundation of true discourse which is always rooted in the being of the things: "the being of things causes the truth of intellect" (esse rei causat veritatem intellectus, Summa theologiae, I, q. 16, a. 1, ad 3um ); and the originally transcendental nature of truth, that is the verum,  as the dispaying of being.

In philosophical Nominalism the aspect of truth as a transcendental, that is, as a property inherent in being, vanishes. Truth simply indicates a quality of propositions; it means only a "true proposition", that is the attribute of propositions when provided with truth (cf. T. Hobbes, De Corpore, 3, n. 7). The doctrine of truth as conformity has found supporters in the realm of scientists marked by a realistic intent. Copernicus, Kepler, Galileo, Newton, Leibniz and many others were convinced that the laws they discovered corresponded to the nature of the things, and that they manifested some of the intelligibility of the world; and that, although it is the researcher who interrogates, it is objective nature which tells us something (see Laws of nature). Search for truth partners science arriving at the general theory of relativity, when Einstein calculated the precession of the perihelion of Mercury (an anomaly of its planetary motion that had perplexed astronomers) discovering that the new theory better explained the movement of the planet, with much greater precision than had the Newtonian theory.

Nevertheless, the idea of truth as conformity can be understood according to diverse meanings, some of which are merely formal, so nullifying its realistic content. Here has its origin the constant criticism against the notion of truth as conformity claimed by Descartes and Spinoza. One of the principle objections, which actually leads to the disintegration of the realistic dimension of the true, is the Spinozan premise according to which the bond of truth is that found between the idea and the mental representation of it. The idea is true in itself, in virtue of its perfection, not in virtue of some correspondence that it has with any thing. The causal link of the true is, therefore, overturned in the sense that conformity with realityoriginates from the truth of the idea. When one no longer deems that it is the conformity that establishes the truth of the idea, the form of true thought must be searched for in the thought itself and must be deduced from the nature of the intellect. Beginning especially with Schelling ( System of Transcendental Idealism, 1800) and later in Hegel (Science of Logic, 1812-1816), idealism will pick up such concepts and provide them with their conclusions.

Where there is the rejection or criticism of the idea of truth as conformity one discloses an unresolved dualism of Kantian origin between thought and reality. This is found in considerable fashion in Heidegger, Apel, Habermas, etc. This point will be discussed further on (see below, n. 6 and III).

On the other hand the concept of truth as correspondence in its realistic meaning has been reflected upon many times in the 19th and 20th centuries by thinkers such as Bolzano, Meinong, Positivistic authors, but also by Thomistic philosophers such as Gilson, Maritain, Fabro, and Lonergan. These last philosophers opposed to the attempts of dividing the concept of truth setting aside an idea of truth for hermeneutic sciences and another idea for the natural sciences (being the former characterized by the "truth" of understanding and interpreting, and the latter by the "method" of verifying, as Gadamer intends in some way). In 20th century thought there is a substantial acceptance of the idea of conformity in scientists and philosophers alien to such deconstructive slippage, among whom are Popper and Tarski. These philosophers recognize that the valid idea of truth as correspondence. Popper (cf. Objective Knowledge, 1972; Unended Quest, 1974) is more sensible to the realistic element there implied, while Tarski, with his semantic theory of the true, reduces the correspondence to linguistic formalizations. The Popperian reintroduction of the concept of truth as conformity was required by the theory of "fallibilism," albeit in the long run, since such terminology would not make sense if it did not presuppose that scientific theory, which had been denied by the facts, was in some way conformable to reality. This implies that fallibilism, rather than being understood as the gateway to skepticism, as it sometimes can be, is instead a form of "meliorism" (as it was intended also by Peirce).

Beyond the theoretical facet, the idea of truth as correspondence or adaptation remains valid. In the case of "practical" truth, such conformity as adaptation holds both in the noble desire towards law (moral truth), and in the intention that moved the act (premoral o "technical" truth). It is of no small importance to remember that for Kant good and evil (or moral truth in general) means conformity or deformity of freewill in respect to the law (cf. Religion within the Limits of Reason Alone, 1793, ch. I). For Aristotle, at least in the field of practical reason, truth is a correspondence of the uprightness of desire (cf. Nicomachean Ethics, VI, 1139a, 30). In the case of following the example of someone as rule for truth, the idea of truth presents itself as conformity between a teacher/role-model and a disciple: we conform ourselves to someone because we trust him or her. One receives truth while entrusting and committing oneself in a personal relationship. In these cases the first meaning (a) of truth (see supra ) draws near to and encapsulates the fifth meaning (e), that is truth as conformity to a certain law or person. In its succinct strength the concept of truth as adaptation or conformity between reality and the act of a subject includes everything. It surpasses even the fundamental level of declarative truth, applying oneself also to the moment of the action, including the action of following someone, where the work of "making something true" takes place.

Here truth appears as something or someone to whom one renders testimony (a typical example is religious experience), conforming and adapting to that which is requested and/or to a living witness.

It seems, however, that one must speak of truth in various ways (as one does with the word "being") meaning by this that there is truth in the metaphysical, scientific, moral, esthetical, and hermeneutic senses. In each of these the concept of conformity or correspondence does not apply in an univocal nor an equivocal sense but an analogical one, that is according to specific modes. Such a concept remains normative, although attempts to abandon the definition of the adaequatio may have influenced certain areas of philosophy and theology, in which a spreading distrust has recently developed towards this analogical conception, almost as if it were a hindrance, a mere formal expression, an impoverishment or even an attempt to the value of mystery. Nevertheless, in nullifying the concept of truth in its original foundation wherein it expresses conformity (whether between thought and reality, or will and law, or teacher/role-model and disciple) it is no longer possible to think or to operate anything whatsoever in which the idea of precept, reference, or measure continues to be present. As a consequence the very act itself of understanding of faith ( intellectus fidei) loses meaning. The encyclical Fides et Ratio, however, presents as unavoidable the concept of truth as conformity (cf. nn. 56 e 82).

The hermeneutical positions carefully considered also approach at least formally such a criterion of truth. In the present case this means a conformity of the interpretation to what that must be interpreted (the interpretandum ). Every author, positing an interpretation, holds it to be true, although one often retains a definitive analysis as unreachable. In the consideration of truth as interpretation the accent lies heavily on the hermeneutical character of our experience of the world. In regard to this, one may remember the positions of U. Betti (Teoria dell'interpretazione, 1955) and L. Pareyson (Verità e interpretazione, 1971), according to whom the one and same truth embodies and expresses itself in many historical formulations which represent the temporal coming of the sole and non-temporal truth. According to P. Ricoeur (The Conflict of Interpretations, 1969), if the conflict of diverse interpretations attests our finite humanness and our "being situated", that is our necessarily limited context, it also attests the effort of moving towards a better and more conforming interpretation. The same diversity of interpretations points towards something that can resolve it. Different from the latter, is the radical and deconstructive hermeneutical position, wherein according to Derrida (Of Grammatology, 1968) one denies every form of objective hermeneutics, and according to Vattimo ( Oltre l'interpretazione, 1994) truth as conformity refers to an openness understood as a metaphor for living. In these last perspectives, the risk of a metaphoric dissolution of the concept of truth remains high.

It is useful to add that the terms adaptation, conformity, and correspondence do not imply an "exhaustive dominion" of an object by the intellect. Even the simplest object of knowledge is never definitively known or exhausted in its multiple features. The criterion of truth as adaptation includes non-adaptation as well. Namely, it indicates the openness of association between the mind and reality, which is never conclusive, and therefore indefinitely susceptible to new developments.

2. Truth as Display, Openness, Evidence, Direct Contact, Discovery. To understand truth in this second fashion is proper to various schools of thought. To begin with there is Empiricism in its many forms, including Epicureanism, which holds that truth is given in the act of sensible perception capable in itself of demonstrating the thing as it is. A notable instance of truth understood as a display and direct contact had already been expounded upon by Aristotle (cf. Metaphysics, IX, 1051b, 22ff). The Cartesian concept of truth also applies, which substitutes the criterion of conformity with that of immediate evidence, proper to a distinct and clear idea. Both the phenomenological movement initiated by Husserl - which maintains the idea that phenomenological intuition of essences permits us to reach truth - and the doctrine of truth as non-obscurity, discovery, a-létheia made famous by Heidegger (cf. On the Essence of Truth, 1930), find itself within this orientation. The latter author reproaches the entire philosophical tradition after Plato and the Greek philosophers to have adulterated the original sense of truth as alétheia (unveiling) and emphasizing instead the idea of orthòtes (correctness of speech), that ones forms in a judgment. In all these cases, the true is that which immediately presents itself as phanerogamic evidence (from the Gr. phaìnein, to show, appear, manifest) that cannot be denied. At the heart of this idea is that reality is self-manifest. Despite the possible and historically verifiable difficulties inherent in the discussion, the first (a) and second (b) understandings of truth are not opposed to one another. Instead, the first implies the second as a key component, necessary but not sufficient. But it does not always occur as such. The positions held by Heidegger and Maritain will be considered later (see below, III).

The present concept of truth, referring to openness, to an opening towards new dimensions of reality, alludes to the truth as discovery. The logic of truth is also the logic of an unveiling, unthought-of, novelty, so emphasizing that the concept of truth is completely equivocated if understood only as a reflection of that which is already noted. The idea of truth as discovery fits into the dynamic of conformity. It is the discovery and conformity of a new response founded on a new question; it conveys all that is included in the first (a) idea of truth. Namely, the primary, active task of the intellect never stops discovering the true. Within its research, action and speculation are intimately unite.

3. The Concept of Truth as Revelation. Such a concept indicates the revealing, by divine initiative, of certain aspects of being unknown to us. While in the preceding cases the idea expressed is that reality unveils itself to us, that is, that reality (not entirely but partly) is supplied with a character of self-disclosure, here a positive divine intervention is instead necessary, capable of taking off that veil that surpasses the possibilities of human intellect. With revelation one crosses over the divide that lies between the finite and the infinity and presents to humanity the unveiling of a mystery. The One who unveils is the Word or divine intellect, since He is the truth itself. The Word reveals, both creating and inserting into things a lógos that reflects aspects of the original Logos, discovering, through a positive religious revelation, both something of the life of God and of the ultimate destiny of human life. This intuition is often presented by scientists such as Einstein who attests for example: "Certain it is that a conviction, akin to religious feeling, of the rationality and intelligibility of the world lies behind all scientific work of a higher order. The firm belief, which is bound up with deep feeling, in a superior mind revealing himself in the world of experience, represents my conception of God." (The World as I See It [London: J. Lane, 1955], p. 131). The other conception, which correlates without contradiction the truth as conformity, is proper to Christianity, as found in Augustine, Anselm, Aquinas, etc.

These two ideas provide grounds for an adequate reflection on the truth and for a dialogue between science and faith. The truth of creation, which can be rationally founded on the level of metaphysics, and the Logos immanent within it, is found in many ways, both explicitly and implicitly, as the foundation of much research. If the cosmos is able to "speak" to the human intellect, it is because there exists an original design proper to it, because in the former there is a Word which expresses itself in various ways, a lógos and a truth present everywhere and refracted indefinitely in every fragment of creation. Upon this one bases the truth of analogy, which makes a certain knowledge of God possible starting from the knowledge of created things. More or less consciously, science with its research places itself within the horizon implied in metaphysics and unveiled in Revelation (cf. Wis 9:1; 16:12; 18:14).

4. Truth as Coherence. This is proposed in critical philosophy. In the thought of Kant again we encounter truth as conformity, understood however as a mere "nominal" definition, whereas the "formal" criterion of truth is introduced as consistency of thought with itself, namely, alignment of thought with the general and necessary laws within the intellect. That which contradicts these laws —maintains Kant in his Critique of Pure Reason— is false because in such a case the intellect contrasts with its very own laws, namely, with itself. In fact, in this work, Kant, accepting and presupposing the nominal definition of truth as an alignment of knowledge with its object, observes that "the merely logical criterion of truth, namely, the accordance of a cognition with the universal and formal laws of understanding and reason, is nothing more than the conditio sine qua non, or negative condition or all truth." This requires the completion of a passage to the transcendental (analytic) logic capable of displaying the elements of pure knowledge of the intellect and its principles, without which no object can be absolutely thought: it is the logic of truth (cf. Critique of Pure Reason: "Transcendental Logic," Introduction: III. "Of the Division of General Logic into Analytic and Dialectic").

In this position truth is the agreement of a proposition within the system of other propositions. In other words it is the concordance or conformity of propositions among themselves instead of with reality. This conclusion establishes the greatest outcome of antirealism and links itself with the problematic Kantian idea of the thing in itself (noumenon), which Hegel in his Science of Logic sarcastically criticizes. In criticizing the separation between thought and being introduced by Kant, which serves as the origin of an unlimited series of equivocations on the problem of the true, Hegel sought to arrive at an idea of logic not as formal science but as a science of truth, employing his criterion of identity between the rational and the real.

One could, however, distinguish between formal and material truth. The former would be the logical coherence of deductions from postulates or premises without contradicting itself. The latter would be the truth as concordance with reality. The statements of pure geometry are true if they are coherent with the axioms conventionally postulated at the beginning. Nevertheless, this formal truth is not enough seeing as it has been detached from reality, and must be integrated with material truth understood at least as compatibility of assertions which express empirical facts. According to M. Schlick there is nothing inappropriate to describe such a compatibility using the old, yet good phrase "concordance with reality" —as it seems opportune (cf. The Foundation of Knowledge, 1934, in Logical Positivism, ed. A.J. Ayer [Westport: Greenwood Press, 1959]). Vice versa, the neopositivism of Carnap and of Neurath understands truth as the coherence of propositions among themselves, a theory that the previously mentioned author, Schlick, holds to be completely inadequate. In fact, the theory of truth as coherence does not provide any univocal criterion of truth since it is logically possible to arrive at any number of systems of propositions internally non contradictory, but among them (that is externally and reciprocally) incompatible, with the result that one would arrive at the idea of a multiple truth not just a double truth. The notion of truth as coherence is also present in the English idealist authors at the end of the 19th century, among whom worth noting is F.H. Bradley (cf. Appearance and Reality, 1893).

5. Truth as Conformity to a Rule or to a Person. Such a conception of the truth can produce two versions: the first is the primary understanding of truth (a), as previously seen to be truth as conformity; but there is another version of truth as coherence (d), when, as in criticism, conformity of thought with the necessary laws of the intellect implies the non-contradictory coherency of thought with itself. The concept of truth as conformity to a law has very important area of validity in moral truth, which can be understood as conformity of the human act to moral law. This remains formally valid also in the case in which the rule is understood as the place of an adequate and presently active free will. One thinks of the position of Hans Kelsen (1881-1973) and his pure doctrine of positive law.

6. Truth as Inter-Subjective Consensus. Such a notion of truth adds the search for inter-subjectivity to truth understood as coherence. It is the conception affirmed by recent authors of philosophy of communications, such as Apel and Habermas. They search for an ideally unlimited inter-subjectivity of consensus. For these authors truth is both a presupposition, in a sense that the speaker assumes among the conditions of speaking the truth and truthfulness, as well as the final aim of unlimited communicative action that take places in the community, namely to reach a convergence between all our beliefs. It remains the subject of doubt whether the agreement sought for is only inter-subjective and linguistic or objective and real, based upon an effective conformity of being. Another question concerns the extension of the unlimited community of communication. Does it include the transcendental or, in principle, it is primarily limited to the level of the dialogue among humans? It is a risk of the doctrine of truth as inter-subjectivity to identify inter-subjective knowledge with valid knowledge as such. On the other hand, the idea of Wittgenstein who holds that we cannot escape language does not oppose the doctrine of conformity, provided that we  understand conformity as the correspondence of a proposition with something that can be expressed in language and that, precisely through the language, it reaches the res, i.e. the real thing.

Within the doctrines of truth as coherency in an open world, and truth as inter-subjectivity in an instable world, the reference to empirical reality is intentionally cut off. Therefore, the idea of truth as inter-subjectivity can be either near or far to that of conformity. In the latter case the idea of conformity remains disguised and expressed as an asymptotic conformity to the reality of a system of propositions inter-subjectivity has established. If with the criteria of truth-coherency science is able to create an unlimited number of systems of pure propositions without effect and real incidence, then with the truth-inter-subjectivity model it would build a system of propositions which give to us much power over nature but with some disagreement on both sides.

7. Truth as Utility and Efficiency. The definition of truth as effectiveness contains two similar but not identical lines of thought. The first maintains that truth is that which is helpful or useful for life. The second maintains that truth explicates an instrumental or functional effectiveness. Friedrich Nietzsche (1844-1900) promulgated the first idea. According to him, "true" is that which turns out useful for life. The falsehood of a judgment is not yet an objection against it (cf. Beyond Good and Evil, 1886, I, 4). For Nietzsche truth is not something existential to discover but rather something to create out of the potentiality of life. To the question "What is truth?" he answered: "A mobile army of metaphors, metonyms, and anthropomorphisms —in short, a sum of human relations, which have been enhanced, transposed, and embellished poetically and rhetorically, and which after long use seem firm, canonical, and obligatory to a people: truths are illusions about which one has forgotten that is what they are; metaphors which are worn out and without sensuous power; coins which have lost their pictures and now matter only as metal, no longer as coins." (On truth and lie in an extra-moral sense, 1873, I). W. James (1842-1910), although not strictly connected to Nietzsche, held the idea linked to pragmatism that in the area of morality and religion the truth consists in the capacity to offer effective solutions to problems. Other authors enlarged the field considering true that which could both amplify human knowledge and control over the universe, as well as improve the moral relationships between individuals. A similar but not identical attitude is present in the pragmatism of J. Dewey (1859-1952), which places the emphasis on an instrumental and functional characteristic capable of etching into nature and society various cognitive procedures endowed with truth, that is with effectiveness. Dewey leans towards a form of "instrumentalism" in the sense that the same activity of thought is a directed activity or execution which modifies the conditions in which the objects present themselves and orders them in a new fashion. The concepts are therefore instruments with which we contemplate and modify objects (cf. Reconstruction in Philosophy, 1920).

III. Further Reflections on the Concept of Truth

Because the consideration of the question of truth is so copiously polysemous a further step is needed to determine the distinct modalities of what it means "to be true." Three considerations follow.

The first modality considers the very existence of things. In other words, things are how they are, they are true: verum est id quod est, wrote Augustine (Soliloquia, II, 5). Truth is reality. It stands in its own sovereign and proud indifference. It guards its own secrets. We are the ones who interrogate truth. We call this modality "ontological truth." The place of this truth is in the things according to the degree of being each of them possess: «each thing possesses so much truth as it possesses being.» (Aristotle, Metaphysics, II, 993b, 30). The second modality is declarative truth. It is expressed in judgment and assumes the form of adaptation between judgment and realty. This second modality, "declarative truth," can also be called "logical truth." The place of this truth is the mind, in the sense that it is the act of the mind that conforms itself correctly or not to reality. In connecting correctly or erroneously a subject with its predicate, thought turns out to be true or false. In this modality, truth is the relationship between the intellect and the thing in as much as it is knowable. The third modality expresses the idea that things, in the manner in which they are, refer back to and reflect the divine creative intellect (or the human designer) on whom they depend. The level of the first modality is consequent with, and fulfills within the third level, to which we attribute the name "absolute ontological truth." It is also in this modality that the formula of coherence applies, which is two-sided and in the present case is understood as adaptation of the thing to the intellect that puts and holds the latter in existence (not adaequatio intellectus et rei, but rather adaequatio rei et intellectus).

In the second and third determination the concept of truth manifests an intrinsically relational structure. It is the relationship between thought and being. The formula that expresses the "logical" truth as conformity (Lat. adaequatio intellectus et rei ) highlights with its same linguistic and semantic structure the relational character of truth as a relationship between the intellect and an object. The intellect then opens up to otherness in itself. As a consequence, thought is not closed upon itself, but can progress in knowledge. There is truth, therefore, where there is thought; truth is in relation to thought. If by hypothesis there was a universe without any form of thought, there would neither exist any declarative truth since there would be no thought to think or express it.

Since declarative truth is a relationship, the intentionality in the concept of truth changes according to the conception that is formed by the two poles of the relation. In post-modern thought the criticism is often turned toward the side of the mind, placing emphasis on the crisis or death of reason as inadequate to comprehend reality and life. In Cartesian or Rationalistic philosophy it is rather from the understanding of being (the res) that equivocations stem. Being or res are understood in an immanent manner as they were the idea or the "representation of the object." On this basis, the problem as to whether the mental ideal represents reality becomes unsolvable (this question was overcome in the classical position, where ideas and concepts do not "represent" but they just "present" the object). Continuing along this road, truth ends up being understood as the correspondence between the thinking subject and as the inner product of thought's activity. In doing so, truth becomes a kind of coherence between thought and itself.

In the doctrines that distance themselves from the truth as conformity one finds an undeserved reduction or incomprehension of the concept of res. In Empiricism, res is only that which is sensible, something one can see or touch. The critique of Naturalism, including that of certain sectors of theology far from Empiricism, attacks the concept of truth as conformity by stating an erroneous total identity between res and material thing. In other words, it does not take into consideration the transcendental significance of res. Realism, therefore, is not "thingism" since res is a transcendental notion convertible with that of being. In "Coherentism" res disappears; truth is no longer a link with another thing, but a mere logical and internal coherence. Also when considering truth as inter-subjective consensus res appears uninteresting, or it might be of interest only as an asymptotic reference in a system of assertions.

The idea of truth as conformity is homogenous with three assumptions that are central in both epistemology and metaphysics. This means that the best understanding of truth requires considering it in union with such three assumption, namely: "moderate realism"; the possibility of "intellectual intuition"; the fundamental doctrine of "intentional identity between thought and being." Unfortunately, these three central points are often ignored by many doctrines of truth. Regarding the first, we refer here to the specific article of this Encyclopedia (see Realism) with the sole clarification that moderate realism (Aristotle, Aquinas, Maritain) is distinct from metaphysical realism which Hilary Putnam (born 1926) is concerned with, from the fact that it (i.e. metaphysical realism) does not pretend to see reality from "God's point of view," like Putnam's, not without serious equivocations, defines. Here it must be recalled that besides Putnam, various authors in the Anglo-Saxon world, such as Dummett and Quine, offer a quite a lacking account of Realism: for instance, they are silent on moderate realism because, perhaps wrongly, they confuse it with the "absolute realism" of Platonic origin. The second and third assumptions are the heart of the philosophy of being's epistemology, which modern philosophy often loses in two ways: rejecting intellectual intuition and presupposing, in a dualistic fashion, that there exists an insurmountable barrier between thought and being. These equivocations, present in the work of Kant, persist in analytical philosophy and remain in post-Popperian and post-empiricist epistemologies with an anti-realist flavor. This persistence continues (as for example in Quine) and tends to lose that minimal element of realism present in logical empiricism through the valuation of sensible perception. For these motives it is difficult to expect from the mentioned schools of thought an effective recovering of the doctrine of truth as conformity, capable, that is, to move beyond the nominal or verbal acceptance of the established formula. This is so because the very presuppositions of an ontological and epistemological order are lost, and are no longer able to render such a formula true, valid, and evident.

Such an equivocation seems noticeable in the philosophies of communication. One sees this intent in the ample study of Karl Otto Apel (born 1922), Fallibilismus, Konsenstheorie der Warheit und Letztbegründung (in "Forum für Philosophie", Philosophie und Begründung, Frankfurt 1986, pp. 116-211). The author does not completely reject the concept of truth as conformity. He thinks it is necessary in order to be respectful of common sense, which is not subject to doubt, in so that the assertion "the wall is white" is true if and only if the wall is white. However, he empties the assertion of its meaning since he believes that it is impossible to discover some truth criteria that could verify such conformity. The "Apelian opposition" takes place between two poles. On the one hand there is the recognition that the theory of truth as correspondence is a natural intuition regarding the truth of enunciations, an intuition which is presupposed as a necessary condition for all theories on truth. On the other hand of the spectrum lies the simple rejection of truth as conformity, qualifying it as a formal and empty concept. Apel is subject to Kantian dualism and is not able to grasp the doctrine of intentional identity between thought and being in certain areas. As a consequence, the acceptance of the presupposition of critical philosophy on the separation between thought and being transforms the concept of truth from a relation between the mind and things, or between subject and object, into a relation between objects. In this new relation it would never be possible to verify their correspondence because it would lack a superior point of observation in which the cognitive relation between the knower and the known should be established from outside. This is an expected outcome, once the absolute exteriority between thought and being is presupposed. Working under this guise, Apel maintains the inversion between facts and propositions (the concept of "fact" or of the "existing state of the thing" is, in turn, definable only by recourse to the concept of a "true proposition") and abandons the inferential discourse, that starting from empirical evidence rises up to its cause (inferential or analytical methodology which arrives at the effects from the causes). The big question remains whether the inter-subjective consensus depends on the truth of the judgment or vice versa, whether truth bases itself upon consensus. All valid knowledge has the ability to produce consensus but it does not base itself upon consensus.

Various other forms of "fear for truth" which manifest themselves here and there in contemporary philosophy are of scarce theoretical importance. Trying to put the idea of truth in crisis, they secretly have extra-theoretical motives, often reducible to the very problematical idea that stable, objective truth should be regarded as a form of violence. In some other cases, claim is made that objective truth is an affront to the values of tolerance and pluralism (this last fear confuses the due tolerance towards people with tolerance towards ideas, forgetting that false ideas cannot claim such an indulgence).

IV. Aspects of the Concept of Truth in the Philosophy of the 20th Century: Jacques Maritain and Martin Heidegger

Among contemporary philosophers, perhaps Jacques Maritain (1882-1973) and Martin Heidegger (1889-1976) have meditated most intensely on the question of truth. The former renewed the classical interpretation with vigor and the latter reinterpreted it in an original albeit ambiguous way.

1. Jacques Maritain's View. The meditation on the nature of truth, understood within the framework of meaning demarcated by the concept of correspondence, constantly occupied the reflections of the French philosopher. Among his many treatments, the most explicit are found in Réflexions sur l'intelligence et sur sa vie propre (1924) and in Distinguer pour unir: ou, les degrès du savoir (1932). Here the truth (of an assertion) is reached in the judgment and determined as "the conformity between the act of our spirit that unifies two concepts into a judgment, and the existence (might it be possible or real) of the thing into which those two concepts take form." Or, also, "if the identification of two terms of a proposition made by the spirit corresponds to an identity in a thing, then the spirit is true." There is, therefore, declarative truth if the objects of thought inherent in the subject and in the predicate and associated in a proposition (which are diverse within themselves and are terms of distinct cognitive relations) become identical with the thing and take form in it. While diverse notions cannot obviously be identical, a notion can be identical to a thing that another notion is identical to as well. In the judgment "Peter is white", the two notions "Peter" and "white" are different, and yet both are identifiable with the object "Peter." Renewing the classical position, Maritain attributes a key-role to the judgment. His role consists in raising the spirit beyond the level of simple essence (or of the notion present in thought) to the level of the thing or subject that owns existence. The judgment restores to the thing its unity, which the simple apprehension, grasping different objects of thought, had disconnected. Here the existential function of judgment is in play, in the sense that with it and in it the intellect "seizes" existence.

The adaptation between the intellect and the thing, which is the proper act of the mind in judgment, presupposes the (intentional) unity-identity between the thought and the thing before expressing the judgment. According to Maritain, in the act of knowing, the thing (in the measure in which it is known) and the thought are not only simply united, but they are one. As Aristotle says, the intelligence in act, is the intelligible (that is the object as known) in act (on this theme, see V. Possenti, Approssimazioni all'essere, Padova 1995, pp. 28-34). However, thought is not a copy or a model of the thing in the manner that all determinations of the thing are those of thought. It is necessary to introduce a certain disjunction between the thing and thought. The things are in thought not in an ontological  but rather intentional manner. And it is exactly this distinction that gives birth to the possibility of error. At the same time it is required to affirm the profound unity between thought and being, in the sense that knowledge is knowledge of being and this knowledge is fulfilled in the concept. The final stage of conceptual knowledge is the thing itself, entitatively present in reality and intentionally in the intellect. As such, the question posed by Kant concerning the link between the representation in the mind and the existent thing out of the mind is answered. Kant , who often confined his learning to the German scholastics of the post-Leibnizian and post-Wolffian slant, did not seem to be aware of the diverse ways of dealing with intentionality, as previously mentioned here.

2. The Problem of Truth according to Heidegger. It is well known that Heidegger recognized truth as adaequatio, understood as the correctness of judgment. However, he subordinated it respectively to the truth as disclosure (Gr. a-letheia) , or non-concealment, linking the latter idea to the image of a "clearing" (Ger. Lichtung). According to the German philosopher, only the alétheia, that is the disclosedness understood as clearing, can establish the possibility of truth. It is in the non-hiddeness of the open clearing where the being-here (Ger. Da-sein ) can be primordially experienced, and it does so before being understood as the result of being correctly exhibited and rightly enunciated (cf. Being and Time [Albany: State of New York Univ. Press, 1996], pp. 196-211). In the clarification of the double modality of the true, Heidegger uses a terminology in itself dualistic. Alétheia and Lichtung signify precisely the truth as a unveiling, whereas veritas and Wahrheit denote the declarative truth, understood reductively only as correctness of enunciation.

While it is a plausible hypothesis that in the non-concealment or disclosedness of the Heideggerian alétheia one appeals to the existence of the things or to their phenomenological manifestation, this approach does not consider the problem of "to whom" or to what subject the thing manifested, nor does it examine the role of thought. The Heideggerian reflection on the truth of being in the double sense of the truth that belongs to being or ontological truth, and the truth expressed about being or declarative truth, does not consider the role of thought nor the axiom according to which, to have truth, there must be a thought thinking of it.

When one meditates on the dense content of On the Essence of Truth (1930), one can conclude that the German philosopher thought long and hard on the question of the true without ever really coming to any positive conclusion because he did not reach the final, decisive step, failing to recognize, unlike Maritain and Wittgenstein, that in the ante-predicative moment there is a kind of identity between thought and reality. Heidegger saw the importance of the problem but did not succeed in understanding the heart of the matter and, therefore, was destined for failure. The outcome of his attempt was a change of the essence of truth. He affirms in his work titled Nietzsche (1961), that "in the history of being, the event first manifests itself as changing the essence of truth.»  Leaving aside the determination of adaequatio , which the German thinker could not accept any longer, seeing as he preliminarily mislaid the antecedents that rendered it necessary and valid, he adopted a "new" determination of truth: «the essence of truth is liberty." (cf. Being and Time, § 44). And this consists in leaving the thing (Lat. ens ) to be. Liberty, leaving space to the thing, allows it to manifest itself. Heidegger's ancient phenomenological heritage is evident in this position, whose horizon of understanding is analogous to the first of the three modalities of being true. At the same time, being is not an object of a conceptual grasping.

The Heideggerian meditation realizes that between the sphere of thought and the sphere of reality a sort of "bridge" has to exist, so that the problem of truth can be addressed. He wonders "how shall we ontologically understand the relationship between the ideal and the real of knowing,"  a question that expresses,  albeit with different words, the same one asked by Kant and the problem of intentionality. Nevertheless, the nature of such a bridge has not been fully developed. Rather, the idea of an unclear, ontological scission between the real and the ideal order still remains (cf. Being and Time, § 44 and On the Essence of Truth). Consequentially, one falls within the Kantian pattern of the separation between thought and being, between the ideal and the real. Such radical anti-intellectualism in Heidegger and a deficit of reflection on the nature of knowledge weighed heavily in the final outcome. In its place, the suggestion was put forward to remain open and available for that which manifests itself in a clearing (Lichtung), in the history of being.

On these aspects one could profitably turn to the positions of Aristotle and Hegel where, different from Kant and Heidegger, the question of intentionality of thought and of intentional identity between thought and the object are adequately positioned. "In general, the mind when actively thinking is identical with its objects." (Aristotle, De anima, III, 431b, 18). Also on the side of sensation the act of the sensible and of the sense are the same and singular act (cf. ibidem , 425b, 26f ). For Hegel the old (pre-critical) metaphysics had a higher conception of thought, since it held that things and the act of thinking the things coincided with each other in themselves; that thought in its immanent determinations and the true nature of the things were one and the same content. So it is affirmed in the introduction to the Science of Logic where the Hegelian polemics towards the "thing in itself" and the presupposed separation between the phenomenon and the noumenon is implacable.

V. Truth within Judaeo-Christian Revelation

In Revelation a rich idea of truth is transmitted to us, one that the Bible deepens and clarifies throughout the history of salvation. In the Scriptures a new element of "stupor" is added. Not only is nature intelligible, but so too is the Word of God. Both speak to us, albeit in different ways. Interestingly, for Galileo God was the author not only of the Scriptures but also of the "book of nature", as recorded in the famous letter to Fr. Benedetto Castelli, on December 21, 1613. The present inquiry will continue to look for the significance of truth in the Old and New Testaments. Then, it will focus on the person of Jesus Christ and finally on a few statements on truth in the documents of the Second Vatican Council.

In the Old Testament, and in general in Hebrew thought, the term "truth" (Heb. 'emet ) evokes certainty, fidelity, and constancy. It is in this sense that truth as conformity is understood. Truth is understood just as much as something that openly appears, and cannot be hidden or silenced, as much as to veracity, that is, the ability to tell the truth and not deceive. The God of fidelity is the same as the God of truth (cf. e.g. Ex 34:6; Ps 31:6). Psalm 31 precisely testifies to the truth of God in contrast to the vanity of idols (v. 7: "You hate those who serve worthless idols, but I trust in the Lord").

If we intend truth as the unveiling manifestation of reality just as it is, then Revelation presents truth as the light that illuminates reality, the world and us. It offers security and salvation to a threatened existence. Ultimately, it is not a doctrine but a person. The source of such an active revealing is Jesus Christ, the true light that illuminates every man who comes into the world. The prologue of St. John's Gospel presents Christ as the incarnate Word, full of grace and truth (cf. Jn 1:14). He is the Logos, who gives consistency, existence, and intelligibility to the world. Walking in the truth, which actually means walking in God and with God, is an essential requirement for human beings, for whom Jesus offered himself saying: "I am the way, the truth and the life." (Jn 14:6). The importance assumed by truth is amplified beyond that of a logically coherent discourse, since action and freedom are implied. "If you remain in my word, you will truly be my disciples, and you will know the truth, and the truth will set you free." (Jn 8:31-32). This does not imply a mere theoretical knowledge but an existential truth that enters the human heart and helps us to be free, removing us from lies and hate and rebellion toward God. The person who knows the truth is "from God" and the love of God dwells within them.

If these religious and contemplative developments presuppose the idea of truth as the combination of true assertions that are conformable to reality, then the existential significance of truth as something that is ultimately a person, prevails as its most important meaning. This is evident in the encounter between Jesus and the Roman Procurator Pilate who inquired of the former: "Then are you a king?" Jesus responded, "You say I am a king. For this I was born and for this I came into the world, to testify to the truth. Everyone who belongs to the truth listens to my voice." (Jn 18:37). Following this Pilate asked, "Quid est veritas? — What is truth?". Perhaps he put the problem in a distracted manner, almost with annoyance and skepticism. He was in a hurry and therefore he was unable to wait for the answer. Intending to close the issue he turned to the crowd, to the priests, and to the scribes asking, "I find no guilt in him. Do you want me to release to you the king of the Jews?". Some medieval authors imagined with far less haste that within Pilate's question the answer was already divinely contained, a simple anagram of the first question which resonates thus, "Est vir qui adest." Jesus clarified to Pilate that He Himself was the truth. Quid est veritas? Est vir qui adest —What is truth? It is the man who is here before you.

If in the canonical Gospels there is no recorded response of Christ to the question posed by the Roman Procurator, one finds a sentence of notable worth in the apocryphal gospel of Nicodemus, intent on narrating the last phases of the life of the Nazarene from the trial forward. In this account Jesus poses the problem to Pilate but then adds: "Truth is from heaven" (therefore, one may interpret from God). The dialogue proceeds with a question from the Roman Procurator, "Is there not truth on earth?" Jesus responded: "You see how those who speak the truth are judged by those who have authority on the earth." The anagramic answer implied in St. John's gospel converges with the explicit response found in the apocryphal account: Truth is something divine; it is God Himself.

This brings about an intensification of human searching, a more acute solicitation of the spirit, as will be evident in the examination of a decisive reference in the New Testament. "You shall love the Lord, your God, with all your heart, with your whole being, with all your strength, and with all your mind." (Lk 10:27). In this way Jesus responded to the doctor of the law who had interrogated him on which was the first and most important commandment. Meditating on the response and drawing parallels to verses in the Old Testament (esp. Dt 6:1-9) one realizes that the lóghion of Jesus deepens and integrates the Old Testament, in which the part et ex omni mente tua (with all your mind ) does not appear. This may be an important and valuable clue to the questions posed by Christ regarding loving God (and the truth). They are understood in a fuller manner, as in addition to the heart, soul, energies, now the mind enters, with its incoercible tendency to know the true until it finds rest and joy in it: nos vero quia credimus, rationem quaerimus (we believe, then we look for reasons).

When in the first letter to Timothy we read, "This is good and pleasing to God our savior, who wills everyone to be saved and to come to knowledge of the truth" (1Tm 2:4), the question arises to which truth allusion is being made. Not an exclusively epistemological or scientific truth is evoked here, a truth that one exhausts in enunciations, but an existential and salvific sense of truth. Revelation is the generator of a new rationality, not only proposing a new truth, new areas of knowledge, new objects never before discovered, but also prompting and arranging the human soul to be open to the whole of reality, the center of which is the incarnate Word. Revelation gives to the human mind more amplified horizons and an intensified heightening of its intellectual act, by which it discerns and values everything upholding the best. The mind thinks in Christ, searches in him and with him. It is able to form a communion of thought and searching beyond the frontiers of time and space. It can then, establish a redeemed rationality, capable of positively ordaining the rational act in the multiplicity of its operations. The mind is ever desirous to draw upon Christ as the source, in whom the fullness of divinity lives bodily and where all the treasures of science and knowledge are found (cf. Col 2:3 and 2:9).

It is useful to remember this broadened outlook when discourse turns to the declarative character of the true. It does not seem opportune to contrast concept and event with their respective logic. It would be an opposition deprived of meaning according to which truth would be, on the one hand, a universal concept while, on the other, an event, punctual in itself. The Christian event conveys an new idea of truth, meant as a synthesis between what is universal and that which is "eventual," historical, personal, expressed by the helpful concept of the Universale concretum ("concrete universal"), mainly applied to the Incarnate Word. At its highest point, Christian truth is a concrete universal, and, ultimately, a Person. In the Incarnation the highest realization of the concrete universal occurs, where time and eternity, the universal and singular events aid and unify with one another. That is not possible in a similar manner for any other kind of event, which remains therefore structurally inferior to such a full capacity of meaning. The unity of the God-man depends on divine initiative. "The Eternal enters time, the Whole lies hidden in the part, God takes on a human face." (Fides et ratio, n. 12). Rationalism's criticism, according to which Christianity, in as much as it is linked to history and to events, could no longer communicate to reason in a universal and convincing fashion, shows here its fallacy.

With the Second Vatican Council comes a renewal and a certain updating of ideas. Remarkableis the premise according to which the truth of God that shines in Revelation, takes place by means of actions and words (Dei Verbum, n. 2). Such an idea of truth is not reducible solely to the abstract and doctrinal element. The "metaphysical" capacity of the human spirit to know God, with the natural light of reason and starting from created things, is there re-affirmed (cf. Dei Verbum, n. 6). The Declaration on religious freedom, Dignitatis humanae, affirms that "all men should be at once impelled by nature and also bound by a moral obligation to seek the truth, especially religious truth." This same Declaration clarifies immediately after: "They are also bound to adhere to the truth, once it is known, and to order their whole lives in accord with the demands of truth." (n. 2).

VI. The Relation between Faith and Science

In the Modern Age, with the impetuous development of science, the dialogue between faith and science has encountered serious difficulties, symbolized in the "Galileo Affair" (see Sacred Scripture). In the last decades the situation has changed and a general opinion is growing that such a dialogue is now possible and necessary. In science and faith there exists two diverse, but not at all contradictory, searches for the truth, correctly understood as involving different levels. The fact that today science and faith speak of truth without much embarrassment looks quite different from what is occurring in many sectors of contemporary philosophy. When one avoids a universal "fallibilism" wherein the relative fallibilism of scientific theories becomes a fallibilism applied to all knowledge, the dialogue between faith and science, although it might encounter difficulties, in principle it does not find irresistible obstacles. A science conscious of its limits is objectively open to dialogue with Revelation. Both aim to recognize a sovereign intellect that governs the universe. Yet, their paths are diverse in that God is the beginning for faith and the end for science.

If science, philosophy and faith are called to dialogue and to cooperate, the fundamental motive is that there exists an intrinsic insufficiency of each of the three to be substituted by the others and to occupy the entirety of the cognitive domain. A notable example is offered by the scientific theory of the Big Bang (see Cosmology). It would seem to prove empirically in favor of a "temporal beginning" or commencement of the universe. Currently, the figure of about 14 billion years is favored, after proposed decades ago figures of 4 and then 10 billion years. Philosophy and Revelation do not deal with a recordable origin but with a "beginning" or "ontological origin." Just as science cannot have jurisdiction of such an "ontological beginning," so Revelation and philosophy cannot claim jurisdiction of an empirical, temporal origin.

It is not superfluous to add that while the Big Bang remains a scientific theory subject to continual revision and could even be abandoned in the future, in the search for an ontological beginning philosophy achieves a certain undeniable stability. This means that the "statute of truth" in science and in philosophy manifest considerable differences, in the sense that while the extension of the former is greater than that of the latter, the reverse is true in regards certainty and stability. Philosophy at its best (ontology and natural theology) reaches truths which are limited in number, essential in content, stable in the manner of knowledge in respect to those truths treated by scientific theories which are multiple, less essential, and mutable. From such considerations the importance of dialogue between science, philosophy and Revelation is made evident and cannot be abandoned since the development and deepening of scientific theories create new questions. On the other hand, in scientific research, questions often arise concerning the origin of the universe, its order, beauty and meaning, the existence and nature of free will, and the presence of a design in the cosmos. The burden of a response to these questions lies upon the shoulders of philosophy and theology, unless science improperly adopts an absolutist attitude.

The points of conflict between science and faith stem for the most part from two sources: a) the ease, often arising from dogmatism, with which sectors of scientific culture has little by little maintained without restrictions all-encompassing theories on the world. It began initially with the "truth" of mechanism, latter giving way to the dominance of the truth of electrodynamic claiming a comprehensive explanation for all phenomenon, and arriving, perhaps, at the global truth held today by genetics; b) inadequate exegetical approaches, which in the case of Galileo touched upon in certain aspects the Church's Magisterium as well, which sought to defend in a literal and immutable sense certain verses of the Scriptures, written using natural language. In the last 30 years new perspectives have arisen which have positively interested the science-faith (and theology) dialogue. According to J. Polkinghorne, they are summed up as follows: the rejection of Reductionism; the evolutionist interpretation of the universe in terms compatible with the theological doctrine of continual creation; a certain renewal of a philosophy of nature and a philosophical cosmology; traces of a new interest in natural theology; a series of speculations in a manner in which physical process can remain sufficiently open to receive the action of human and divine agents (cf. Polkinghorne, 1998, p. 1). To these factors, one could also include another one, that involves a limited but significant attention to finalism. It was a movement censured for centuries but slowly reemerged from the moment in which a purely mechanical explanation of the phenomenon of nature was rejected as completely untenable. Contemporary scientific cosmology credits an open and evolvable cosmos in which a teleology of the single organism is undeniable, whereas it is more difficult to prove a universal teleology. Presenting the cosmos not as merely deterministic —and thus allowing metaphysics and teleology to reflect upon the theories of continual creation and on the nexus of first cause and second cause— contemporary cosmology seems to go beyond the concept of a solely God mathematical. Responding to the idea that God, the great architect of the Universe, is a pure mathematician (this was the premise of the astronomer Sir James Jeans), Hans Jonas maintains, for example, that he is certainly much more than this (cf. "Is God a Mathematician?," in Measure 2 [1951], pp. 404-426).

If science were identified with a pure instrumentalism that does not describe real states of the world, and faith with a foggy sentimentalism without any object, they would have nothing to contribute each other, and could proceed on their own ways. It is, however, dubious that such neutral solutions are satisfactorily accepted. The problem of the relationship between faith and science begins when both advance cognitive claims. On the part of faith this happens with a declaration of absolute Realism: fides terminatur non ad enuntiabile sed ad rem, that is, the act of faith concerns reality as believed, not simple formulas ; and these, in turn, are valuable in the measure in which they express reality. As a consequence, in the science-faith relationship it is not sufficient to maintain that science knows and religion/faith merely helps human beings for their behaving (such was the gist of Spinoza's position and is also today a very common way to judge religion).

The theory of the complete reciprocal irrelevance between science and faith, which includes promoters on both sides, appears on the whole to be unsustainable, though this idea could contain some truth. Science that belongs to the empirical and measurable field cannot comment on the meta-empirical. On the other hand, faith leaves freedom of research to science in its own proper field. Furthermore, when they occupy the same "material object" (for example, humanity, life), science and faith consider it under different "formal objects" and on the basis of principles, methods, and goals of knowledge that are proper to each of the two cases. Nevertheless, the thesis of a complete separation does not seem in the final analysis valid because if science and faith knew something real, though under different prospects, it will be always possible to compare two fields of knowledge on the edges or overlapping areas, and thus verify where they are in agreement or contradiction. Indeed, there are frequent cases in which a further elaboration of philosophical nature grafts itself upon scientific data. That the model of total separation and reciprocal irrelevance is unsatisfactory can be verified in the Galileo affair, where in many ways a divide existed between a strong realistic conception of science and a realism in faith that was erroneously recognized only in a literal interpretation of Scripture.

Now, since the doctrine of double truth is absurd (serving more as a way of escape from desperation) the truth of science and faith requires that they are harmonized and not merely juxtaposed. Vittorio Mathieu correctly observes, that "it is necessary that these two truths not only counter, but also encounter each other without causing any harm."  ("Spazio della scienza e spazio della fede," in Scienza e fede, Assisi 1982, p. 10). It does not make much sense, therefore, to place a difference between absolute truth and objective truth, intending that the former (not universal) belongs to faith and the latter to science, which would be objective but not absolute. As much as being objective, the truth is universal, valid for all diachronically and synchronically and therefore absolute.

Even if faith does not have anything to say concerning the structure of the cosmos and its laws, very few would sustain that the way in which the universe is structured is completely irrelevant to religion. In this respect, ideas have changed from the past. Contemporary physics and cosmology, as diverse as they are from ancient sciences, present an image of the universe that is not opposed to Bible. In addition, it is more akin to biblical Revelation than to the closed Greek cosmological model, highly charged with necessity, as well as to the model formed by modern mechanicism. In the latter the universe was thought as a perfect and autonomous mechanism, jump started by a mechanical God, similar to a clock-maker, and who thereafter was disinterested in the world. Such a depiction, analogous to Deism, was one of the principle paths leading to atheism. Samuel Clarke (1675-1729), a disciple of Newton, maintained that the idea of a mechanistic cosmos, as if it were resembling a clock, is nonetheless a materialist view, and the cosmos seen as something accidental. Disguised, as it were, in considering God as a supernatural Intelligence, it nonetheless expels God's providence and govern from the world. An open universe, which is changing, contingent, non-cyclic, but marked by an irreversible linear concept of time, is more coherent with the biblical sense of the cosmos than the one marked by the philosophical view of an eternal return because circularity alludes to self-foundation. From current scientific cosmology arises the question of whether the universe is self-explanatory or whether it demands a causa essendi, from which it depends and is held in being. It is metaphysics, not science that responds to this paramount question. However, the latter can offer a greater or minor informative support. Although the Greeks were able to prove the necessary existence of an Absolute, an open cosmos characterized with surprises and contingency appears to be closer to the Biblical faith than a universe marked by fate or by the destiny of an eternal return.

In contemporary physics, one encounters at times the objection that a science based upon "irreversibility" or "chance" of processes would be more divergent from a religious faith in God than a science anchored in deterministic and causal laws. Since, continues the objection, science is abandoning more and more the deterministic conception orienting itself towards a conception of irreversibility and chance, that would render almost unintelligible the idea of a God who regulates nature with invariant laws ultimately depending on Him.

Let us now consider this objection in its dual formation. Regarding the irreversibility of nature, it means simply to point out a limitation of Newtonian physics (in its equations the variable "time - t" can assume all values, positive and negative), and does not put any "charge to God" (so to speak). Since a science that realizes the need for an irreversibility of time and of natural processes is more realistic and adequate than one which does not, the objection raised does not concern God but rather the internal epistemological conflict between a deterministic-reversible science (that is, without a linear concept of time) and a science capable to include irreversibility in its own laws.

The second part of the objection employs that concept of chance. The nature of this word is often unexplained by those who would use it for anti-theological reasons, often to show that chance conflicts with a governing Intelligence. What is chance? Having largely appealed to this concept in his work Chance and Necessity (1970), J. Monod did not unpack and develop the thesis. Instead, it was perspicaciously discussed by Aristotle, who understood chance as a not preordained, random encounter by "two or more causal, independent lines" for which "chance implies causality" (cf. Aristotle, Physics, II, chps. 4-6 and the Commentary made by Thomas Aquinas in In II Physicorum, lects. 7-10). Contrary to the opinion that where there is chance there is no place for causality, the reverse is true (even this point confirms the impossibility of disregarding the cause-effect link). It is not unpredictability and/or the absence of causality that from which chance originates; rather, it originates from a plurality of independent causes and their sudden meeting at a certain point. Thus, the idea of an original or absolute chance is contradictory (see Determinism).

There are no rational motives, therefore, to use chance to reject the idea of an Absolute, as if a universe regulated by a total necessity were more coherent with the idea of God, than a universe managed by random. Rather, the opposite is true, in the sense that a casual event, not possessing a true and proper cause (that which does not have true unity does not have cause, and a random event, the result solely from an encounter of "diverse" causal lines is not an ens per se with its own unity) it reaches a certain unity only in the divine mind. Chance exists for humanity, not for God. One can even maintain that God is in a certain sense more immediately present in chance than in necessity.

In the relationship between science and faith as forms of knowledge, room needs to be left for philosophy, especially metaphysics. While metaphysics investigates the totality of being with the question, «what is all that is and what sense does it have?», science does not consider the meaning of being and its global truth. Rather, by means of empirical verifications it searches for theories and laws capable of coherently unifying vast series of phenomenon and states of the world. In respect to science, metaphysics does not refer to an alter-reality but to the same, however, with a different approach. It searches for the intelligible in the sensible, questioning whether experience is self-explanatory or instead indicates a source beyond experience that provides meaning. While science seeks to master the connections and horizontal references among possible states of the world, metaphysics begins precisely from these states viewed in the light of existence and tries to move from these to their principle and cause.

Various currents of thought, whether they be expressions of Christian thought or forms of Scientism, allege that the elimination of metaphysics constitutes the essential prerequisite for a healthy rapport between science and faith. The latter would then be rendered fuller and more authentic. A faith completely void of metaphysics and a science that does not dabble in the affairs of ontology would be in a much better position for dialogue. It is very dubious that this simplified solution is capable of confronting the complexity of the issue. Indeed, there are good reasons for substantiating the idea that metaphysics is useful to both science and faith, precisely in proving the existence of a first Cause. This is helpful to the former because it reassures scientists that reality is intelligible and has a meaningful sense, and to the latter because it does not reduce faith to a mere feeling of heart.

VII. Truth and Philosophical Realism

One of the greatest problems of modern philosophy, already present in Descartes' system, was formulated with clarity by Kant, who held at once that it was both vital and very difficult to solve: how could something in the mind be a representation of something outside the mind? (cf. I. Kant, Letter to Hertz, February, 21, 1772). It is the problem of "intentionality" and of the "concept", that is again recalled, intentionality understood at least as the original phenomenon that connects thought and being, mind and world. Modern philosophy was conditioned by this problem. The missing and uncertain solution had caused decisive consequences including the attempt to transform the concept of truth. In fact, it is impossible to know anything real if from the beginning one puts an insurmountable ditch between the knower and the known, which in the end could depend on a form of oblivion of being and its intelligibility. According to most of the post-modern culture, being and existence are mute and non-revealing. Being is not self-revealing (nor as a symbol) because it is a mere res extensa that does not reveal anything. When one reaches this state of facts, which is at the same time existential and cultural, reality appears to the subject as something foreign, hostile, with which one cannot interact in a contemplative or friendly way, but only with the attitude of challenge and dominion. On the basis of a fractured intimate spiritual experience between oneself and the world, between oneself and being, the subject feels thrown into a hostile world that seems to arise from nothing and to end into nothing. As a consequence, the tendency emerges to dominate the world because it is seen as nothing other than a threat to humanity. The immense global activism of the Western world can recognize its origin here.

These various linked themes regarding truth refer to the question of realism. It is sufficient to mention that according to the realistic vision the activity of philosophy and science discovers something real, that is not simply placed in the things by us. On the other hand, the anti-realistic vision often implies that we discover only that which we have put into the things as projections of our mental categories. For decades a lively debate has been taking place concerning precisely the question of realism, in the field of the philosophy of being, in Anglo-Saxon post-analytical philosophy and in the sciences. Karl Popper and John Polkinghorne discuss exactly in what sense is such a debate oriented, and with their observations this study concludes. "Theories are own inventions, our own ideas; they are not forced upon us, but are our self-made instruments of thought: this has been clearly seen by idealists. But some of these theories of ours can clash with reality; and when they do, we know that there is a reality; that there is something to remind us of the fact that our ideas may be mistaken. And this why the realist is right." (K.R. Popper, "Three views concerning Human Knowledge," in Contemporary British Philosophy, edited by H.D. Lewis [London - New York: Allen & Unwind - Macmillan, 1956], p. 385). "Like most scientists, I believe that the advance of science is concerned not just with our ability to manipulate the physical word, but with our capacity to gain knowledge of its actual nature. In a word, I am a realist." ( Polkinghorne, 1998, p. 104).


Philosophical and theological aspects: K.O. APEL, Understanding and Explanation. A Transcendental-Pragmatic Perspective (Cambridge MA – London: MIT Press, 1984); E. BERTI, Le vie della ragione (Bologna: Il Mulino, 1987); G. COLOMBO, “Dalla Aeterni Patris (1879) alla Fides et ratio (1998),” Teologia 24 (1999), pp. 251-272; I. DE LA POTTERIE, Gesú veritá. Studi di cristologia giovannea (Torino : Marietti, 1973); I. DE LA POTTERIE, La vérité dans saint Jean, 2 voll. (Roma : Biblical Institute Press, 1977); E. GILSON, Le réalisme méthodique (Paris : Téqui, 1935); E. GILSON, Réalisme thomiste et critique de la connaissance (Paris : Vrin, 1939); A. LIVI, Filosofia del senso comune (Milano : Ares, 1990); J. MARITAIN, Réflexions sur l'intelligence et sur sa vie propre (Paris Nouvelle libr. Nationale, 1924); J. MARITAIN, Existence and the Existent (1947) (Garden City : Image Books - Doubleday, NY 1956); J. MARITAIN, “De la verité,” Approches sans entraves (Paris : Fayard, 1973), pp. 59-76; J. MARITAIN, A preface to Metaphysics. Seven Lectures on Being (1934) (Salem NH: Ayer, 1987); J. MARITAIN, Distinguish to unite, or, The Degrees of knowledge (1932) (Notre Dame, IN: Univ. of Notre Dame Press, 1995); J. PIEPER, Wahrheit der Dinge. Eine Untersuchung zur Anthropologie des Hochmittelalters (München: Kösel-Verlag, 1957); J. PIEPER, Living the Truth (San Francisco: Ignatius Press, 1989); K. POPPER, Critical approaches to science and philosophy (1964), edited by Mario Bunge Transaction Publisher, NJ – London: New Brunswick, 1999); K.R. POPPER, Unended Quest. An Intellectual Autobiography (1974) (London: Routledge, 2002); A. POPPI, La verità (Brescia: La Scuola, 1985); V. POSSENTI, Razionalismo critico e metafisica. Quale realismo? (Brescia: Morcelliana, 19962); V. POSSENTI, Terza navigazione. Nichilismo e metafisica (Roma: Armando, 1998); V. POSSENTI, Filosofia e Rivelazione (Roma: Città Nuova, 1999); H. PUTNAM, Realism and Reason (Cambridge: Cambridge University Press, 1983); H. PUTNAM, Realism with a Human Face (Cambridge MA: Harvard University Press, 1990); G. QUELL, R. BULTMANN, Alétheia, in TDNT, vol. I, pp.232-251; G. TANZELLA-NITTI, L'enciclica “‘Fides et ratio’: alcune riflessioni di teologia fondamentale,” Acta Philosophica 9 (2000), pp. 87-109; A. TARSKI, “Der Wahrheitsbegriff in den formalisierten Sprachen,” Studia Philosophica, I, 1933-35, pp. 261-405; W. WILDBERGER, ‘mn (firm, secure), in TLOT, vol. I, pp. 134-157; M. ZUNDEL, Dialogue avec la vérité (Paris : Desclée, 1964).

Truth and science: E AGAZZI, Filosofia, scienza e verità (colloquio con F. Minazzi e L. Geymonat) (Milano: Rusconi, 1989); T. e I. ARECCHI, I simboli e la realtà (Milano: Jaca Book, 1990); G. DEL RE, Una chiave di lettura: l'essere e la verità come fondamenti della scienza, in T. Torrance, Senso del divino e scienza moderna (Vatican City: LEV, 1992), pp. 5-37; S. CHANDRASEKHAR, Truth and Beauty. Aesthetics and Motivations in Science (Chicago: University of Chicago Press, 1987); P. DUHEM, The Aim and Structure of Physical Theory (1906) (Princeton, NJ – Oxford: Princeton University Press, 1954); J. LADRIERE et al., La nature de la vérité scientifique (Louvain-La-Nueve: Ciaco, 1986); R. MARTINEZ (ed.), La verità scientifica (Roma: Armando, 1995); J. POLKINGHORNE, Belief in God in an Age of Science (New Haven – London: Yale University Press, 1998); G. TANZELLA-NITTI, Passione per la verità e responsabilità del sapere. Un'idea di università nel magistero di Giovanni Paolo II (Casale Monferrato: Piemme, 1998), cap. IV: “Università e verità,” pp. 131-172; R. TIMOSSI, Dio e la scienza moderna (Milano: Mondadori, 1999).