Proofs for the Existence of God

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PROOFS FOR THE EXISTENCE OF GOD . Early generations of Christian thinkers accepted God's existence as a given that needed no proof and was surmised on the basis of immediate evidence in an act that did not clearly distinguish faith from reason. The dominant exponent of this approach was Augustine (d. 430), who posited, for instance, an awareness of God as "first truth" in the intuition of truth as such that occurs in the depths of human consciousness. Bonaventure (d. 1274) was a legitimate heir of Augustine in the medieval period, as was Blaise Pascal (d. 1662) in the modern era. Nicolas Malebranche (d. 1715), by contrast, promoted an ontologism, in which "God" is made the first innate idea implanted in the human mind, of which all other ideas are modifications.

The Ontological Argument

Those who have sought God's existence by deploying the processes of reasoning have done so in one of two ways: either a priori or a posteriori. The first approach derives God's existence from an idea of him in the consciousness of the knower. The original formulation of this argument is that of Anselm of Canterbury (d. 1109); it describes God as "that than which a greater cannot be conceived." Such a notion demands, for Anselm, God's real existence (Proslogion 2), and indeed entails it as something necessary (Proslogion 3). Various versions of this argument appear in the works of René Descartes (d. 1650), who argues that God cannot be conceived as nonexisting (Third Meditation ), and Gottfried Wilhelm Leibniz (d. 1716), who, echoing John Duns Scotus (d. 1308), declares that if God is possible, he exists (New Essays concerning Human Understanding 4.10). Among the contemporary defenders of the ontological argument are Norman Malcolm, Alvin Plantinga, and Charles Hartshorne. Its two most trenchant critics are Thomas Aquinas (d. 1274), who views it as making an unfounded move from the ideal to the real order (Summa theologiae 1.2.12), taking Anselm's idea of God to include the concept of real existence but not the actual exercise thereof; and Immanuel Kant (d. 1804), who insists that existence is not a predicate included in any concept and so can only be encountered empirically ("Of the Impossibility of a Cosmological Proof of the Existence of God," Critique of Pure Reason A592/B620 ff.).

The Cosmological and Teleological Arguments

An alternative position repudiates any a priori approach on the ground that nothing antecedes or explains God's beingness. Finite entities of the world, however, are not the explanation of their own reality but rather are the effects of a transcendent creative cause. This explains a posteriori the mere existence at least of a primal cause, which Christians have identified materially with God. In the language of Thomas Aquinas, arguments of this kind are not designated "proofs," but five "approaches" or "ways" (viae ) to God that function as "prerequisites to faith" (praeambula fidei ) in the God of revelation. The starting points of all such arguments are facts readily observable in the world of ordinary experience: motion, causality, contingency of existence, grades of ontological perfection, and intrinsic finality. The nerve of the thought process is causality: efficient, exemplary, and final. An infinite regress in any series of such causes is deemed unintelligible as long as the ordering is an essential and not merely an accidental one. The rational intelligence is thus led to postulate the existence of God as primal or ultimate causenot as the first member of the series but as the analogical cause of the series as such. The lineaments of such a procedure were not original with Christian thinkers but were already to be found in Plato, Aristotle, Ibn Sīnā (Avicenna), Ibn Rushd (Averroës), and Moses Maimonides. Significantly, Thomas himself never refers to these movements of thought as establishing God's existence, only as justifying the judgment that "God is"; all that is claimed, then, is the legitimacy of using the copula "is" of God in a transsubjective sense.

The Moral Argument

This conviction within Christian thought, of an intrinsic intelligibility at the heart of reality bespeaking a transcendent ground to the real order, reached its clearest expression in the thirteenth century but began to erode into skepticism with the rise of nominalist theology in the fourteenth century, especially with William of Ockham (d. 1349). Immanuel Kant, in the late eighteenth century, insisted in his Critique of Pure Reason that human understanding has no access whatsoever to any possible realm of meaning beyond the phenomenal, which is given immediately to consciousness and structured further by categories innate to the subjectivity of the knower. God is thus, for Kant, a regulative idea formed by the mind to legitimate the ethical order. Thus, ethics becomes the grounding principle for postulating God's existence, rather than vice versa, as had been the case in the past. Moral imperatives mean, simply, postulating one who imperates; any question of a real referent to that concept outside consciousness lies beyond the competency of human reason.

Judaism and Islam

Jewish thought eschews all efforts to prove God's existence, seeing this as established beyond dispute in the prophets, whose concern is God's moral governance. Philo Judaeus (d. circa 50 ce), however, under the stimulus of Greek and Arabic thought during the Hellenistic period, integrated rational reflection on the world with what the scriptures teach. Maimonides (d. 1204), in the medieval period, advanced two forms of the cosmological argument: one from motion and one from the contingency of existence. Among moderns, Moses Mendelssohn (d. 1786) stresses the role of reason in those areas in which revelation appears unnecessary, while Franz Rosenzweig (d. 1929) argues that the existential encounter dispenses with rational inquiry and itself constitutes revelation. This position accords with Martin Buber's (d. 1965) way to God as the eternal Thou in humanity's dialogue with every finite thou.

Islamic thought did not employ reason on things divine that were taught in the Qurʾān until medieval times, when Ibn Sīnā (d. 1037), distinguishing essence from existence, argued for God as the necessary existent. Ibn Rushd (d. 1198), integrating Islamic tradition with his understanding of Aristotle, maintained that the metaphysician can demonstrate the revealed truth about God available to believers in metaphorical language. Ibn Rushd's influence, in the form of Latin Averroism, extended to the University of Paris in the thirteenth century and to the universities of Bologna and Padua until the mid-seventeenth century.

Modern Atheism

G. W. F. Hegel (d. 1831) returned to the ontological argument; he maintained that finite consciousness was a "moment" in the self-enactment of Absolute Spirit, which thus assumed prerogatives formerly ascribed to divinity. Ludwig Feuerbach (d. 1872) explicitly launched atheism against Christian thought by inverting Hegel's thinking and reducing all references to the infinite to mere projections of finite spirit confronted with its own seemingly inexhaustible resources and aspirations. This tendency soon manifested itself as psychological atheism with Sigmund Freud (d. 1939), as socioeconomic atheism with Karl Marx (d. 1883), as ethical atheism with Jean-Paul Sartre (d. 1980) and Albert Camus (d. 1960), and as anthropological atheism with Maurice Merleau-Ponty (d. 1961), thereby pervading much of modern Western thought.

The Post-Atheistic Age

Reactions against this denial of any accessible signs of God's existence began with Friedrich Schleiermacher (d. 1834), who postulated, below the level of either reason or will, a feeling (Gefühl) or immediate awareness of the utter dependence of consciousness upon the sustaining reality of the transcendent whole, amounting to a God-consciousness within humankind. Roman Catholic thought, for its part, in the constitution Dei filius approved by the First Vatican Council in 1870, repudiated a "traditionalism" on the one hand and a "semirationalism" (in which, after a revelation from God, reason is able on its own to understand the pure mysteries of God that form the content of such revelation) on the other, opting instead for the possibility of a natural knowledge of at least God's existence. Paul Tillich (d. 1965) set a new tone in analyzing existential encounter, as opposed to metaphysical reflection; what he called disclosure experiences enable humankind to posit questions of ultimacy that are then answered in correlation to the revelatory act of a self-manifesting God. Wolfhart Pannenberg has recently argued, in reaction to Karl Barth's neoorthodoxy, which makes all acknowledgment of the true God a matter of religious faith, that history in its universality, open to human reason, offers hypothetical grounds for the reality of God. The available "proofs," then, are simply anthropological ways of formulating the question with precision and urgencythe question that humanity itself is. Because history has not yet run its course, all answers are provisional in kind, based upon anticipating the consummation of history in the resurrection of Christ.

Karl Rahner (d. 1984) and Bernard Lonergan (d. 1984) have attempted a rehabilitation of Thomas Aquinas's five "ways," viewing them as reflective and logical formulations of a prereflective, unthematic dynamism of finite spirit. This transcendental structure of human consciousness, which actualizes itself in the historical and categorical order, is described by Rahner as a pregrasp (Vorgriff) of God himself under the formality of holy mystery. In a radically different vein, Alfred North Whitehead (d. 1947), originating a movement loosely called process thought, views God as a coprinciple with the world in a universe ultimately not of being but of creative becoming. This argument for the existence of God arises from the need to explain novelty in a self-creative universe without making God an exception to, rather than the prime instantiation of, the metaphysical schema. Here God "lures" the world forward, even as it in turn supplies data for God's own creative advance into novelty (Process and Reality, 1929, 5.2).

Present Status of the Proofs

Much of modern thought, especially that indebted to analytic philosophy, tends to dismiss all talk about proofs for God's existence as meaningless, because no verifiable content can be given to the very idea of God. De facto, neither theism nor atheism is considered to be either demonstrable or refutable by reason. The affirmation of God is taken to be a matter of faith (religious or otherwise) rather than of reasonbut one which, once made, may manifest itself as entirely reasonable.

See Also

Atheism; Attributes of God; Doubt and Belief; Enlightenment, The; God; Nominalism; Philosophy, article on Philosophy of Religion; Scholasticism.


Cobb, John B., Jr. A Christian Natural Theology. Philadelphia, 1965. Chapters 4 and 5 contain an exposition of the argument from Alfred North Whitehead by one committed to its validity.

Dupré, Louis. A Dubious Heritage. New York, 1977. Incisive studies of the ontological, cosmological, and teleological arguments in the light of post-Kantian thought.

Gardet, Louis, and M. M. Anawati. Introduction à la théologie musulmane. Paris, 1948. A basic survey from a Christian perspective.

Goichon, Amélie-Marie. La philosophie d'Avicenne et son influence en Europe mediévale. Paris, 1944.

Guttmann, Julius. Philosophies of Judaism: The History of Jewish Philosophy from Biblical Times to Franz Rosenzweig. New York, 1964.

Hick, John, ed. The Existence of God. New York, 1964. Critical appraisals including the moral and religious arguments in light of present discussions.

Kenny, Anthony. The Five Ways. New York, 1969. A rejection, scholarly and moderate in tone, of each of the "five ways" as based ultimately on an outmoded cosmology.

Küng, Hans. Does God Exist? Garden City, N.Y., 1980. Contemporary argument against atheism and nihilism based on experiencing the trustworthiness of human existence.

Mackie, J. L. The Miracle of Theism: Arguments for and against the Existence of God. Oxford, 1982. Largely rejections of the traditional and contemporary arguments, with emphasis on the negating power of evil in the world.

Maritain, Jacques. Approaches to God. New York, 1954. Detailed defense of the "five ways" of Thomas Aquinas, plus a prephilosophic approach and one based on the dynamism of the intellect.

Mascall, E. L. The Openness of Being: Natural Theology Today. London, 1971. A survey of arguments including those of transcendental Thomism, of process thought, and of empiricism; basically a defense of a metaphysical approach to the question of God against Anglo-Saxon positivism.

Plantinga, Alvin, ed. The Ontological Argument, from St. Anselm in Contemporary Philosophers (1940). New York, 1965. An expository and critical exploration of the argument in its varied forms; does not include Plantinga's own ingenious formulation of the argument he presents later in chapter 10 of The Nature of Necessity (Oxford, 1974).

Smith, John E. Experience and God. New York, 1968. Critical assessments of the ontological, cosmological, and teleological arguments from a pragmatist's point of view. See especially chapter 5.

William J. Hill (1987)