God, Existence of

Most theists tend to think of God as the Supreme Being. Human knowledge and power are strictly limited, while God is omniscient and omnipotent. But humans are beings and God is a vastly superior being. Hence human beings exist and God exists in exactly the same sense. The tradition of Christian theology, however, also contains conceptions of the differences separating God and creatures that are more radical. According to Thomas Aquinas (c. 1225–1274), for example, there is in human beings a distinction between essence, which is to say what human beings are, and existence. But in God essence and existence are identical; God's essence is to exist. God is Being Itself, not one being among others. Thus humans exist and God exists in different though analogously related senses. And an even more radical separation is found in the mystical theology of Meister Eckhart (1260–1328). He distinguishes between God (Gott ) and the Godhead (Gottheit ). The Godhead is an aspect or dimension of divine reality that is above or beyond being. It is neither a being nor Being Itself. Paradoxically, it cannot be said to exist, even though it is the Ultimate Reality. Jean-Luc Marion develops a conception of this sort in his aptly titled God Without Being (1991).

Evidential support for claims about the existence of God comes from several sources. They include religious experience, revelation, and theological reflection. According to William P. Alston's Perceiving God (1991), claims about how God is interacting with a human subject of religious experience derive prima facie epistemic justification from a kind of nonsensory perception in which it seems to the subject that God is performing actions of various sorts. The God encountered in such experiences is taken to be a being capable of inter-acting with human beings. In the Hebrew Bible, when Moses asks God to make known the divine name, God says in response to Moses, "I am who I am" (Exod. 3:14). According to some interpretations, it is revealed by means of this response that God is Being Itself. The idea that God is not just a being among beings thus derives epistemic warrant from scriptural revelation. And in The Courage to Be (1952), Paul Tillich speaks of the God above the God of theism. He also claims that the divine Ultimate Reality is not a being or even Being Itself, but is instead the Ground of Being. Theological reflection therefore lends credibility to the claim that God is somehow beyond being.

However, one must turn to certain parts of natural theology if one wishes to find a source of evidence for the existence of God that is sensitive to empirical science. According to Immanuel Kant (1724–1804), natural theology's main arguments for God's existence may be classified as ontological, cosmological, or teleological. Anselm of Canterbury (c. 1033–1109) is the author of the first and most famous ontological argument. He attempted to derive the existence of God from the idea of God as a being greater than which cannot be conceived. But since the premises of ontological arguments are supposed to be knowable a priori and so independent of human experience of the world, such arguments do not in any way rely on scientific knowledge of that world.

Cosmological arguments do appeal to premises about the empirical world that is the object of scientific inquiry. Two familiar cosmological arguments are among Aquinas's celebrated five ways of proving the existence of God. One starts from the premise that there are now things undergoing change and things causing change; it concludes that an unchanging first cause of change exists. The other starts from the premise that there are contingent things that might not have existed; it concludes that there is a necessary being on which contingent things depend for their existence. Because the premises of these two arguments invoke only very general features of the world that humans experience, their truth does not depend on the details of the scientific worldview. There are, however, cosmological arguments that are sensitive to such details. In his contribution to Theism, Atheism, and Big Bang Cosmology (1993), William Lane Craig argues for God's existence from physical cosmology. According to Big Bang cosmology, the cosmos began to exist twelve to fifteen billion years ago. Reasoning from the principle that anything that begins to exist must be brought into existence by something, Craig concludes that God brought the cosmos into existence. Craig's argument is, of course, quite controversial. In his contribution to Theism, Atheism, and Big Bang Cosmology, Quentin Smith contends that Big Bang cosmology provides the basis for a successful argument to atheism.

But science bears most directly on natural theology through teleological or design arguments. The best known design argument is contained in William Paley's Natural Theology (1802). Paley argues for an analogy between the order displayed by biological structures, such as the human eye, and the order of mechanical devices, such as watches that are known to be products of design, and he concludes that God designed those biological structures. This sort of analogical design argument was subjected to devastating criticism by David Hume (1711–1776), and Darwinian mechanisms involving variation and natural selection have successfully explained a great deal of biological order. So Paley's design argument has lost its popularity.

More recent design arguments appeal to other sorts of natural order. In The Existence of God (1979), Richard Swinburne argues that the temporal order in the cosmos expressed by natural laws together with the fact that nature is composed of only a few elementary building blocks are evidence of design. He concludes that this evidence boosts the probability of God's existence. Others have drawn attention to the fact that various parameters such as certain physical constants and initial conditions of the cosmos at the Big Bang must lie within narrowly restricted limits if life is to evolve. They contend that God fine-tuned those parameters for the purpose of producing either life of some sort or other, or human life in particular. These arguments too have turned out to be controversial.

And in the United States, the Intelligent Design creationism movement aims to overthrow Darwinism. Michael Behe, one of the prominent figures in this movement, argues in Darwin's Black Box (1996) that molecular and cell biology have revealed irreducible biological complexity that cannot be explained in terms of Darwinian mechanisms of variation and natural selection. Behe's view is that such complexity is the product of divine design. Intelligent Design creationism has been vigorously disputed by many scientists and philosophers. A balanced and comprehensive presentation of the views on both sides of this new outbreak of warfare between science and religion may be found in Intelligent Design Creationism and Its Critics (2001), a volume edited by Robert T. Pennock. It remains an open question whether any part of scientific knowledge supports or under-mines belief in the existence of God.

See also Cosmological Argument; Design; Intelligent Design; Ontological Argument; Teleological Argument

Bibliography

alston, william p. perceiving god: the epistemology of religious experience. ithaca, n.y.: cornell university press, 1991.

behe, michael. darwin's black box: the biochemical challenge to evolution. new york: free press, 1996.

craig, william lane, and smith, quentin. theism, atheism, and big bang cosmology. new york and oxford: oxford university press, 1993.

marion, jean-luc. god without being, trans. thomas a. carlson. chicago: university of chicago press, 1991.

paley, william. natural theology. london: faulder; philadelphia, pa.: john morgan, 1802.

pennock, robert t., ed. intelligent design creationism and its critics. cambridge, mass.: mit press, 2001.

swinburne, richard. the existence of god. oxford: clarendon press, 1979.

tillich, paul. the courage to be. new haven, conn.: yale university press, 1952.

philip l. quinn