Theism, Arguments For and Against
THEISM, ARGUMENTS FOR AND AGAINST
Philosophy of religion enjoyed a renaissance in the final third of the twentieth century. Its fruits include important contributions to both natural theology, the enterprise of arguing for theism, and natural atheology, the enterprise of arguing against it. In natural theology philosophers produced new versions of ontological, cosmological, and teleological arguments for the existence of God. In natural atheology problems of evil, which have always been the chief arguments against theism, were much discussed, and philosophers debated proposed solutions to both the logical problem of evil and the evidential problem of evil.
Building on work by Charles Hartshorne and Norman Malcolm, Alvin Plantinga (1974) formulated a model ontological argument for the existence of God that employs the metaphysics of possible worlds. Let it be stipulated that being unsurpassably great is logically equivalent to being maximally excellent in every possible world and that being maximally excellent entails being omnipotent, omniscient, and morally perfect. The main premise of Plantinga's argument is that there is a possible world in which unsurpassable greatness is exemplified. From these stipulations and this premise he concludes, first, that unsurpassable greatness is exemplified in every possible world and hence in the actual world and, second, that there actually exists a being who is omnipotent, omniscient, and morally perfect and who exists and has these properties in every possible world. The argument is valid in a system of modal logic that can plausibly be claimed to apply correctly to possible worlds. Plantinga reports that he thinks its main premise is true and so considers it a sound argument.
However, he acknowledges that it is not a successful proof of the existence of God. A successful proof would have to draw all its premises from the stock of propositions accepted by almost all sane or rational persons. The main premise of this argument is not of that sort; a rational person could understand it and yet not accept it. In other words, not accepting the argument's main premise is rationally permissible. But Plantinga maintains that accepting that premise is also rationally permissible. Since he regards it as rational to accept the argument's main premise, he holds that the argument shows it to be rational to accept its conclusion. As he sees it, even though his ontological argument does not establish the truth of theism, it does establish the rational permissibility of theistic belief.
According to William L. Rowe (1975), Samuel Clarke has given us the most cogent presentation of the cosmological argument we possess. It has two parts. The first argues for the existence of a necessary being, and the second argues that this being has other divine attributes such as omniscience, omnipotence, and infinite goodness. As Rowe reconstructs it in contemporary terms, the first part of the argument has as its main premise a version of the principle of sufficient reason, according to which every existing thing has a reason for its existence either in the necessity of its own nature or in the causal efficacy of some other beings. It is then argued that not every existing thing has a reason for its existence in the causal efficacy of some other beings. It follows that there exists a being that has a reason for its existence in the necessity of its own nature. Next it is argued that a being that has a reason for its existence in the necessity of its own nature is a logically necessary being. It may then be concluded that there exists a necessary being.
Rowe takes care to ensure that his version of Clarke's argument is deductively valid. What is more, he maintains that the principle of sufficient reason that is its main premise is not known to be false because no one has set forth any convincing argument for its falsity. However, he claims that the argument is not a proof of the existence of a necessary being. As Rowe sees it, an argument is a proof of its conclusion only if its premises are known to be true, and no human knows that the principle of sufficient reason is true. Hence, even if the argument is sound, it is not a proof of its conclusion. Rowe leaves open the possibility that it is reasonable for some people to believe that the argument's premises are true, in which case the argument would show the reasonableness of believing that a necessary being exists. If the second part of the argument made it reasonable to believe that such a necessary being has other divine attributes, then the theist might be entitled to claim that the argument shows the reasonableness of theistic belief. So Rowe invites the theist to explore the possibility that his cosmological argument shows that it is reasonable to believe in God, even though it perhaps fails to show that theism is true.
Richard Swinburne's teleological argument is part of a cumulative case he builds for theism (Swinburne, 1979). Other parts of the case involve arguments from consciousness and morality, from providence, from history and miracles, and from religious experience. Each part of the case is supposed to increase the probability of theism; the case as a whole is supposed to yield the conclusion that, on our total evidence, theism is more probable than not. The existence of order in the universe is supposed to increase significantly the probability of theism, even if it does not by itself render theism more probable than not.
In constructing his teleological argument, Swinburne appeals to general physical considerations rather than specifically biological order. There is a vast uniformity in the powers and liabilities of material objects that underlies the regularities of temporal succession described by the laws of nature. In addition, material objects are made of components of very few fundamental kinds. Either this order is an inexplicable brute fact or it has some explanation. Explanatory alternatives to theism such as the committee of minor deities suggested by David Hume seem to Swinburne less probable than theism, because theism leads us to expect one pattern of order throughout nature, while we would expect different patterns in different parts of the universe if its order were the product of a committee. So the alternatives are that the temporal order of the world has no explanation and that it is produced by God.
It is a consequence of Bayes's theorem that this order increases the probability of theism if and only if it is more probable if God exists than that God does not exist. Swinburne offers two reasons for thinking that the order of the universe is more probable on theism than on its negation. The first is that the order seems improbable in the absence of an explanation and so cries out for explanation in terms of a common source. The second is that there are reasons for God to make an orderly universe: One is that order is a necessary condition of beauty, and there is good reason for God to prefer beauty to ugliness in creating; another is that order is a necessary condition of finite rational agents growing in knowledge and power, and there is some reason for God to make finite creatures with the opportunity to grow in knowledge and power.
The teleological argument plays a limited role in Swinburne's natural theology. Since it is an inductive argument, it does not prove the existence of God. Swinburne does not claim that by itself it shows that theism is more probable than not; nor does he claim that by itself it establishes the rational permissibility of belief in God.
Hence, only modest claims should be made on behalf of these three arguments for theism. Their authors are well aware that they do not prove the existence of God. However, they may show that belief in God is reasonable or contributes to a cumulative case for the rationality of theistic belief.
Problems of Evil
According to J. L. Mackie (1955), the existence of a God who is omniscient, omnipotent, and perfectly good is inconsistent with the existence of evil. If this is correct, we may infer that God does not exist from our knowledge that evil does exist. A solution to this logical problem of evil would be a proof that the existence of God is, after all, consistent with the existence of evil. One way to prove consistency would be to find a proposition that is consistent with the proposition that God exists and that, when conjoined with the proposition that God exists, entails that evil exists. This is the strategy employed in Plantin-ga's free-will defense against the logical problem of evil (Plantinga, 1974).
The intuitive idea on which the free-will defense rests is simple. Only genuinely free creatures are capable of producing moral good and moral evil. Of course, God could create a world without free creatures in it, but such a world would lack both moral good and moral evil. If God does create a world with free creatures in it, then it is partly up to them and not wholly up to God what balance of moral good and evil the world contains. The gift of creaturely freedom limits the power of an omnipotent God. According to Plantinga, it is possible that every free creature God could have created would produce at least some moral evil. Hence, it is possible that God could not have created a world containing moral good but no moral evil.
Consider the proposition that God could not have created a world containing moral good but no moral evil and yet creates a world containing moral good. The free-will defense claims that this proposition is consistent with the proposition that God is omniscient, omnipotent, and perfectly good. But these two propositions entail that moral evil exists and thus that evil exists. Hence, if the defense's consistency claim is true, the existence of a God who is omniscient, omnipotent, and perfectly good is consistent with the existence of evil. Therefore, the free-will defense is a successful solution of the logical problem of evil if its consistency claim is true. That claim certainly appears to be plausible.
Most philosophers who have studied the matter are prepared to grant that the existence of God is consistent with the existence of evil. The focus of discussion has shifted from the logical to the evidential problem of evil. The evils within our ken are evidence against the existence of God. The question is whether they make theism improbable or render theistic belief unwarranted or irrational.
William L. Rowe (1988) presents the evidential problem of evil in terms of two vivid examples of evil. Bambi is a fawn who is trapped in a forest fire and horribly burned; Bambi dies after several days of intense agony. Sue is a young girl who is raped and beaten by her mother's boyfriend; he then strangles her to death. According to Rowe, no good state of affairs we know of is such that an omnipotent, omniscient being's obtaining it would morally justify that being's permitting the suffering and death of Bambi or Sue. From this premise he infers that no good state of affairs is such that an omnipotent, omniscient being's obtaining it would morally justify that being in permitting the suffering and death of Bambi or Sue. If there were an omnipotent, omniscient, and morally perfect being, there would be some good state of affairs such that the being's obtaining it would morally justify the being's permitting the suffering and death of Bambi or Sue. Hence, it may be concluded that no omnipotent, omniscient, and morally perfect being exists.
The first step in this argument is an inductive inference from a sample, good states of affairs known to us, to a larger population, good states of affairs without qualification. So it is possible that no good state of affairs known to us morally justifies such evils but some good state of affairs unknown to us morally justifies them. But Rowe argues that the inference's premise gives him a reason to accept its conclusion. We are often justified in inferring from the known to the unknown. If I have encountered many pit bulls and all of them are vicious, I have a reason to believe all pit bulls are vicious.
William P. Alston (1991) challenges Rowe's inference. As he sees it, when we justifiably infer from the known to the unknown, we typically have background knowledge to assure us that the known sample is likely to be representative of the wider population. We know, for example, that character traits are often breed-specific in dogs. According to Alston, we have no such knowledge of the population of good states of affairs because we have no way of anticipating what is in the class of good states of affairs unknown to us. He likens Rowe's reasoning to inferring, in 1850, from the fact that no one has yet voyaged to the moon that no one will ever do so.
The disagreement between Rowe and Alston illustrates the lack of a philosophical consensus on a solution to the evidential problem of evil. It is safe to predict continued debate about whether horrible evils such as the suffering and death of Bambi or Sue provide sufficient evidence to show that theistic belief is unjustified or unreasonable.
See also Alston, William P.; Bayes, Bayes' Theorem, Bayesian Approach to Philosophy of Science; Clarke, Samuel; Cosmological Argument for the Existence of God; Evil, The Problem of; Hume, David; Mackie, John Leslie; Malcolm, Norman; Modality, Philosophy and Metaphysics of; Modal Logic; Ontological Argument for the Existence of God; Philosophy of Religion; Plantinga, Alvin; Religious Experience; Teleological Argument for the Existence of God.
Alston, W. P. "The Inductive Argument from Evil and the Human Cognitive Condition." In Philosophical Perspectives, Vol. 5: Philosophy of Religion, edited by James E. Tomberlin. Atascadero, CA: Ridgeview, 1991.
Mackie, J. L. "Evil and Omnipotence." Mind 64 (1955): 200–212.
Plantinga, A. The Nature of Necessity. Oxford: Clarendon Press, 1974.
Rowe, W. L. The Cosmological Argument. Princeton, NJ: Princeton University Press, 1975.
Rowe, W. L. "Evil and Theodicy." Philosophical Topics 16 (2) (1988): 119–132.
Swinburne, R. The Existence of God. Oxford: Clarendon Press, 1979.
Phillip L. Quinn (1996)