A standard topic in the philosophy of religion. Because God does not appear to our human senses the way a chair or a desk or even these words do, how do we know God exists?


Philosophers and theologians have proposed many arguments to prove that God exists. Perhaps the four most important are known in technical terms as the ontological, the cosmological, the teleological, and the moral arguments. The names may seem obscure, but the ideas are often more familiar.

If God Is God, God Must Exist

A medieval philosopher named A NSELM (c. 1033–1109) proposed the ontological argument. He argued that only a person who does not really understand what the word God means can ask whether God exists.

According to Anselm, the word God means “the greatest being that we can conceive of.” If we conceived of something greater than God, that something would in fact be God. Our original idea of what was God would have been a mistake.

But, Anselm asked, what is greater, a God that we only imagine, or a God who actually exists? His answer was, clearly, a God who actually exists. As a result, it would be wrong to say that God only exists in people’s imaginations. We can easily conceive of a being who is greater than that God, namely, a God who actually exists. Therefore, Anselm said, God must exist.

It All Had to Start Somewhere Anselm’s argument appeals to some people. But many people, even those who believe in God, suspect that it involves a verbal trick.

A second argument for the existence of God is the cosmological argument. In effect, this argument insists, “it all had to start somewhere.” This argument reminds us that things in the world are caused and have limits. But, the argument goes, for something to be caused and have limits, there must be something uncaused and unlimited, in other words, God.

In technical terms, this argument depends on the idea that an “infi nite regress” is impossible. Consider yourself as a person. Your parents caused you to come into existence. Your grandparents caused them to come into existence. The line extends far back. But can it extend back—regress— forever? On one line of thinking, such an infi nite regress is impossible. Without a fi rst set of parents,
the entire series of generations would never have begun in the fi rst place.

That is certainly true when applied to human life, or better, to life on earth. According to the cosmological argument, the same principle applies to the whole universe. For the universe to exist there must at some point have been a fi rst, uncaused cause, in other words, God.

How Can a Watch Exist without a Watchmaker? A third argument, the teleological argument, points out that nature is not a chaos. It has its own rules, orders, patterns, and designs. But, this argument goes, order and design exist only as the result of planning and intelligence. Could a watch exist if there were no watchmaker? Indeed, the more complex an order is, the greater the intelligence that is required to create it. It requires more mental effort to make a digital-display watch that also keeps track of the date, times laps, and sounds alarms at selected times than it does to make a sundial.

But if order requires intelligence and complex order requires higher intelligence, what about the order and design of the entire universe? Everyone admits that they are larger and more complex than any order and design produced by human beings. The teleological argument says that such magnifi cent order shows that the highest intelligence was at work. In other words, the order of nature proves the existence of God.

In the late 1990s and early 2000s, some people developed a version of this argument called “Intelligent Design.” They argued that evolutionary theory could not explain the origins of complex organic structures like the eye. Therefore, they reasoned, modern biology itself pointed to the existence of God.

More:  Cats In Japanese Mythology

God Must Exist for People to Be Moral

The German philosopher Immanuel Kant (1724–1804) tried a different approach to proving that God existed. He did not start by refl ecting on the nature of the universe at large. Instead, he said that God had to exist if people were to be moral. The argument is subtle, but many people have followed his lead.

Consider, for example, the requirement “Do not murder.” What authority stands behind such a requirement? Certainly it is not simply consensus among human beings. Even if every other human being in our community agreed that murder was acceptable, we would want to say that murder is wrong. Indeed, the Reverend Martin Luther King Jr. made just such a claim when he appealed to a higher law and disobeyed discriminatory laws.

According to the moral argument, this common moral experience shows that God exists. That is because God alone is capable of making moral requirements valid, despite what individual human beings think and say. If God did not exist, what is right would simply be a matter of individual opinion and whim. This chaotic situation is envisioned in Fyodor Dostoyevsky’s novel The Brothers Karamazov (1879–80). In that novel, one character commits suicide to prove that God does not exist.


The classical arguments try to use logical reasoning to show that God exists. Thinkers have taken other approaches in considering God’s existence, too. Like the classical theologians, they conclude that God exists, but they arrive at the conclusion in different ways.

Safe to Say God Exists?

The European philosopher Blaise Pascal (1623–62) adopted a practical attitude to the question of God’s existence. In effect, he asked, What are the costs and benefi ts of believing or not believing in God?Pascal reasoned that if we believe that God exists and are wrong, it costs us relatively little. By contrast, if we do not believe that God exists and are wrong, we might suffer a great deal. Therefore, Pascal said, the best bet is to believe that God exists.

Others, like the Danish philosopher Soren Kierkegaard (1813–55), go a bit further. Kierkegaard says that faith in God is something that religious people have despite all rational proof. To have genuine faith, people need to take a “leap of faith.” Belief in God that results from arguments or balancing costs and benefi ts is not the kind of faith God wants.

The Experience of God

A different approach appeals to experience. People believe things in the world exist because they experience them. According to one approach, people believe God exists because they experience God, too. One person who developed this argument was the Christian philosopher Rudolf OTTO (1869–1937). He described the experience of God as the experience of a mysterium tremendum et fascinans—a profound mystery that was terrifying and overwhelming but also comforting and appealing.

Otto agreed that our experiential knowledge was not quite like our knowledge of a chair or a desk. It was, he said, not certain knowledge but a hunch. (The German word that he used can also be translated as “feeling.”) But, Otto pointed out, hunches play a larger role in our thinking than many people are willing to admit.

What God Really Is

Others suggest that the classical arguments misunderstand God and so try to prove the existence of what God really is not. A good example of this position is process theology.

Process theology sees reality as made up not of things or substances but of processes and relations. When process theologians apply these views to God, they may call into question such views as that God is eternal and unchanging and that he is the fi rst source of all that is. For example, an early process theologian, Henry Nelson Weiman (1884–1975), suggested that God is not an eternal, unchanging, omnipotent person but “the source of human good.”

Process theology has been particularly important for people interested in questions of THEODICY. But process theology may also be helpful in dealing with the existence of God. Most people, for example, think that there is some source of human good, even if they cannot describe it very well.

More:  Mongaku: Good Pious of the Tale of Heike

Possible Worlds and Modal Logic

In the 20th century philosophers began to use a kind of logic known as “modal logic.” This kind of logic talks not about what is but about what might be. For example, talking about possible worlds helps clarify some philosophical issues. These worlds may not be the world we live in, but they are worlds that we can imagine consistently, worlds that make sense.

The American Protestant philosopher Alvin Plantinga (b. 1932) has used this kind of logic to develop a version of the ontological argument. Like many arguments in philosophy, his argument is subtle, and it requires more knowledge of modal logic than most readers will possess, but roughly it goes like this. It is possible for a world to exist in which there is a being who is maximally great. But what does it mean to be maximally great? A maximally great being would be one that existed in all possible worlds, including our own. For such a being to exist in a possible world, it must exist in all possible worlds, including our own.

Many philosophers doubt that this argument actually demonstrates that God exists, and Plantinga himself is willing to grant that. But what he does claim is that the argument shows that it is rational to hold that God exists. Many philosophers also disagree that this conclusion follows from Plantinga’s argument.


European Christians have not been the only people to use these arguments that God exists. For example, a school of Indian philosophy that specializes in logic, known as the Nyaya school, developed all of the classical arguments except the ontological one. But not everyone has found these arguments satisfactory. Some have argued against one argument in making a case for another. For example, the Catholic thinker Thomas A QUINAS (1224–74) argued against the ontological argument in proposing the cosmological one.

Most people make the same objection to the ontological argument. They say that we cannot deduce that something exists simply from the definition of a word. We can only demonstrate that something exists by arguing from what we perceive with our senses. People who object to the cosmological and teleological arguments generally use one of two counterarguments. One counterargument claims that there are other, better ways to explain the characteristics of the universe, such as the theory of biological evolution. These people may view intelligent design the way they view a chemist who attributes the result of an experiment she or he cannot explain to an act of God; it is better simply to say that we do not yet know the cause. The other counterargument says that the cosmological and teleological arguments do not go far enough. They prove that the foundations of the universe exist, or perhaps that what Hindus call BRAHMAN exists, but they beg the question about whether we should call those foundations God. One problem with the moral argument is that it requires a view of morality that was not popular with North American thinkers in the last half of the 20th century.

People may also object to the other approaches mentioned above. For some, the probability of God’s existence may be so small that they see little real benefi t in believing in God. Some may equate Otto’s hunch with hunches about spirits and spooks, making it much less compelling. For some, the God of process theology may not be what they mean by God at all; others may object that process theologians should stop talking about God and just talk about the world instead. Some people who accept the notion that knowledge has foundations take a narrower view of those foundations. Their view denies that God’s existence is really a foundational proposition. Other people, known as “antifoundationalists,” reject the notion that there are foundational propositions altogether.


Philosophers and theologians have not come to any agreement about whether it is possible to prove that God exists. Many reject the attempt as misguided. Others continue to develop and revise arguments for the existence of God.