I begin with a very brief, very general outline of the history of Western philosophical treatments of theism. I then discuss contributions to this history from pagans, Jews, Muslims, Christians, and non-believers. Finally, I make some comments about the range of conceptions of God that is evident in this history.
Historical Outline
Western philosophy emerged in ancient Greece in predominantly polytheistic cultures. The ideas of the various schools of Greek philosophy shaped the intellectual histories of the lands that were subsequently conquered by the Romans. When Christianity rose to be the dominant religion in the declining Roman Empire, the primary intellectual task became the integration of revealed Christian doctrine with that Greek philosophical inheritance. However, after the collapse of the Roman Empire much of the Greek philosophical inheritance became inaccessible to Christian thinkers, and was preserved primarily in the vibrant intellectual climate of the Muslim world. From the Muslim world, that preserved philosophical inheritance then made its way back into Christian intellectual life around the time of the rise of universities, and contributed significantly to a philosophical flowering that has continued to the present day.
While the task of integrating revealed Christian doctrine with Greek philosophical inheritance remained the primary intellectual task throughout much of the extraordinarily fertile heyday of Scholastic philosophy, the primacy of that task came to be questioned more insistently around the time of the dawning of the Renaissance. Rather than suppose that philosophy is entirely subservient to theology, more Christian thinkers came to accept the ancient Greek view that the primary intellectual task is to understand the world and our place in it—a task that, at least in principle, is capable of being pursued without reference to revealed Christian doctrine. As one element in a brew that contributed to serious political turmoil in Christendom, Renaissance Humanism helped to pave the way both for the Reformation and for the rise of modern philosophy and modern science.
As modern philosophy moved towards its culmination in the Enlightenment, its practitioners deemed themselves freer to follow where they took the dictates of reason to lead. For many, this was a version of deism and natural religion; but eventually, for some—and many would put Hume in this category, although others would demur—it was either agnosticism or atheism. Thereafter, the story of theism in Western philosophy becomes a story of many different movements, with very different approaches and views.
Much post-Enlightenment philosophy has been hostile to theism. Materialism, naturalism, positivism, and numerous kinds of criticism have all fueled agnostic and atheist positions. Developments in the sciences—such as Darwinian evolutionary theory—and in the humanities—for example, the search for the historical Jesus and higher Biblical criticism—have been taken to underwrite those views. Very recently, “new atheists,” such as Richard Dawkins, Daniel Dennett, Sam Harris, and Christopher Hitchens, have extended hostility to all manifestations of religion (see Dawkins 2006; Dennett 2006; Harris 2004 and 2006; Hitchens 2007). (For criticism of the “new” atheism, see, for example, McGrath and McGrath 2007.)
But, of course, much post-Enlightenment philosophy has been friendly to theism. Idealism—both Romantic and Absolute—attracted some theists (as well as some who were looking for substitutes for theism). Much the same can be said for phenomenology, existentialism, structuralism, deconstructionism, and various kinds of postmodernism. Moreover, largely in circles occupied by analytic philosophers, there has been a considerable recent renewal of enthusiasm for large parts of Scholastic philosophy. And some—notably Thomists—have maintained a tradition that is continuous with the high points of Scholasticism.
Pagans
There is a theistic tradition that runs through ancient Greek and Roman thought, centered primarily on Plato (429–347 bce) and Platonism. Perhaps there are antecedents for this tradition in even earlier thinkers, such as Xenophanes (570–480 bce). However, there is a clear line of pagan thinkers, who defend a kind of theism, from Plato through to the neo-Platonists of late antiquity—in this line we find, for example, Plutarch (c.45–120 ce), Plotinus (c.204–70 ce), Porphyry (232–305 ce), and Proclus (411–85 ce). Of course, many contemporary theists will insist that the being that the neo-Platonists called “The One” and “The Good” differs in various ways from their God; but there have also been countless Christians down the centuries who have been prepared to say that their God is “The One” and “The Good.”
There are many other channels in Greek and Roman thought that trafficked in talk about God and the gods. Some ancient thinkers were pantheists or panentheists (for example, the Stoics—such as Chrysippus (c.279–c.206 bce)—are perhaps in this camp). Some ancient thinkers were polytheists (arguably, for example, the Pythagoreans—such as Pythagoras (fl. 520 bce)—and the Epicureans—notably Epicurus (341–c.270 bce)). Some ancient thinkers were skeptics, and their skepticism extended to God and the gods (for instance, perhaps, Cicero (106–43 bce) and Sextus Empiricus (possibly second century ce)). The Greek and Roman legacies included a rich diversity of views of God and the gods and an extended record of discussion and debate about these views and related matters.
Aristotle (384–322 bce) was a source for many Scholastic arguments for the existence of God, and yet it is not clear whether he is properly classed as a theist. On the one hand, Aristotle seems to have been a polytheist: he took for granted the existence of the gods in the Greek pantheon. On the other hand, in the development of his cosmology, Aristotle was led to the postulation of a Prime Mover of the celestial spheres, and he attributed to the Prime Mover various properties that subsequent Christians attributed to God: for example, incorporeality, immutability, and absence of potentiality. As we remarked above in connection with Platonism and neo-Platonism, there are many contemporary theists who would insist that Aristotle’s Prime Mover differs in various ways from their God; but there have also been countless Christians down the centuries who have been prepared to say that their God is the Prime Mover.
Jews
While there have been long periods in which Jewish thinkers have contributed little to the main threads of Western philosophy, there have been a number of Jewish thinkers who have made seminal contributions. I shall mention just a few of them here.
Philo (c.15 bce–50 ce) exerted a significant influence on subsequent Christian thought, primarily because he was recognized as one of the first to undertake the task of integrating revealed doctrine with the then still developing legacy of Greek philosophy. In particular, Philo developed a method of allegorical interpretation of scripture that enabled him to “find” Greek philosophical doctrines in the Hebrew Scriptures. This work was a model for early Christian theologians and exegetes. And Philo also developed a theory of the Logos that had some intriguing affinities with Gospel accounts.
During the centuries in which the Muslim world was pre-eminent, there were a number of very significant Jewish philosophers, including: Isaac Israeli (c.855–c.955), Saadiah (c.822–942), and Avencebrol (1021–58). The most influential Medieval Jewish philosopher was Maimonides (1138–1204); and the most notable to have lived in the Christian West was Gersonides (1288–1344). Isaac Israeli and Avencebrol played an important role in the transmission and revival of neo-Platonism in the Christian West; and Gersonides and (especially) Maimonides were key players in the popularization of Aristotle’s works between the twelfth and fourteenth centuries.
Spinoza (1632–77) is one of the most controversial figures in philosophy. He was a scathing critic of traditional religion, a determinist, and a proponent of pantheism (or something very much like it). However, on his account, he was a religious reformer rather than an enemy of religion. Moreover, his abiding preoccupations were as much political as they were metaphysical: he wrote against the background of prolonged religious conflict, and expressly favored democratic and republican institutions that promoted religious tolerance.
The twentieth century threw up a diverse range of Jewish philosophers; I mention just three here. Martin Buber (1878–1965) is noted primarily for his preoccupation with God’s relationship to human beings (though he also collected Hasidic tales, and wrote extensively on the Bible, Zionism, philosophical anthropology, and other topics). Ludwig Wittgenstein (1889–1951) is one of the greatest of all philosophers, and his conception of religious belief has cast a very large shadow—see, for example, Malcolm (1993), Philips (1993) and Arrington and Addis (2001). Emmanuel Levinas (1906–95) studied phenomenology under Edmund Husserl, and was himself a significant influence on Jacques Derrida and a generation of French philosophers.
As suggested by my initial remarks in this section, there is no genuine narrative thread to the Jewish contribution to Western philosophical thought about theism.
Muslims
The Muslim world produced a large number of first-rate philosophers between the eighth and twelfth centuries. While these philosophers were mostly from Persia—centered in and around Baghdad—there were also some from the further reaches of the Muslim empire, in Northern Africa and Southern Spain. Perhaps the most significant of the great Muslim philosophers are: Alkindi (d. 870), Alfarabi (870–950), Avicenna (980–1037), Algazali (1058–1111), and Averroes (1126–98).
Alkindi was a polymath who played a key role in the transmission of Greek philosophy to the Muslim world. He translated many of the key texts into Arabic, and developed an Arabic philosophical vocabulary that was taken over by many of his successors. Moreover, his attempts to incorporate Aristotelian and neo-Platonic doctrines into Muslim philosophy were widely favorably regarded.
Alfarabi was also a polymath, noted for his attempts to make Aristotelian syllogistic logic accessible to those who spoke only Arabic. Although he promoted Aristotelian— or, at any rate, neo-Aristotelian—doctrines, he held that Aristotle’s conception of the Prime Mover required neo-Platonic supplementation, in order to bring it into line with the conception of God that is provided in the Old Testament.
Avicenna was yet another polymath, perhaps most famous for his contributions to medicine. He attempted to give a proof of the existence of God based on his metaphysical views concerning the distinction between existence and essence. Avicenna held the controversial view that unaided philosophical inquiry yields precise truths about the existence and nature of God, the creation of the world, the fate of human beings, and so forth—truths that are perhaps only obscurely implicit in scripture.
Algazali provided a significantly different orientation to Islamic philosophy. He was a skeptical and severe critic of the views of his predecessors (in, for example, The Incoherence of the Philosophers). His systematic Sufism owed much less to inheritance from the Greeks, though some of Avicenna’s ideas found a place in his “occasionalism.”
Averroes was the last great Muslim philosophical polymath. He responded to Algazali’s attack on Aristotelianism with The Incoherence of the Incoherence, in which he argued both that Algazali’s arguments were no good, and that he was attacking a straw man. Averroes reversed Avicenna’s claim that essence precedes existence, and developed his own proofs of the existence of God on this alternative foundation. Perhaps most controversially, Averroes held that theology is subordinate to philosophy, since only the latter can yield demonstrative knowledge.
Other Muslim philosophers who might have been discussed here include: Albumasar (787–886), Alrazi (870–950), Alhacen (965–1040) and Avempace (d. 1139).
Christians
The letters of the apostle Paul (c.2–c.64 ce) involve an interesting fusion of Jewish traditions with elements of Greek philosophy, particularly Stoic and later Platonic moral psychology. The earliest Christian philosophers—Justin (d. 168 ce), Irenaeus (d. 202 ce), Clement (150–212 ce), Tertullian (155–230 ce) and Origen (185–255 ce)—also drew on a range of Stoic and Platonic sources, but they all took the view that Christianity was a corrective to the errors of pagan philosophers: none of the Greeks had a correct conception of God. Of course, the Christian conception of God was itself a work in progress; and, during the period of the first two Councils—at Nicaea (325 ce) and Constantinople (381 ce)—there were significant developments in the Christian conception of God in the thinking of the Doctors of the Western Church—Ambrose (c.337–97 ce), Augustine (354–430 ce) and Jerome (347–420 ce)—and the Doctors of the Eastern Church—Athanasius (293–373 ce), John Chrysostom (317–407 ce), Basil the Great (330–79 ce), Gregory of Nazanius (329–89 ce), and the third of the Cappadocian fathers, Gregory of Nyssa (c.335–c.395 ce).
Between the Council at Chalcedon (451) and the end of the first millennium, there was not a lot of influential philosophical activity. The Corpus Dionysiacum was written sometime soon after 500 ce, and Boethius (480–525) wrote the Consolations of Philosophy just prior to his death. John Philoponus (490–570) was an interesting critic of Aristotle and Proclus (though he had the posthumous misfortune to be declared anathema). Gregory the Great (540–604), while recognized as a Father and Doctor of the Western Church, was notable for his leadership, administration, and diplomacy rather than for the subtlety of his thought. Isidore of Seville (c.560–636) and Maximus the Confessor (580–662) were among those who studied the Corpus Dionysiacum, and who preserved and interpreted late neo-Platonism. Eriugena (800–77) stands out as another significant translator of, and commentator upon, the Corpus Dionysiacum.
Early in the new millennium, we find Peter Damian (1007–72) making vilificatory claims about philosophy. The fathers of Scholasticism—Anselm (1033–1109) and Abelard (1079–1142)—both arrived at a much higher estimation of the virtues of philosophy, and prompted a new emphasis on reason and argumentation. (Anselm had access to Augustine and Boethius, including Boethius’ translations of Aristotle; Abe-lard also relied on Cicero and Porphyry.) Of course, the new estimation of the virtues of philosophy had its detractors, most visibly in the persecution of Abelard by Bernard of Cla...