In chapter 3 of  Existential Reasons for Belief in God; A Defense of Desires and Emotions for FaithClifford Williams makes a critical distinction between two related but different apologetic arguments based on need:

1. The existential argument based upon needs (the one his book is focused on).

2. The evidential argument based upon needs.

Let’s look at each of these in turn.

The Existential Argument

This says that faith in God is justified because it satisfies specific needs. It doesn’t say anything about whether God exists; it simply says that as faith in God satisfies basic human needs, that’s sufficient justification for believing in God. The three-step argument is:

1. We feel these basic human needs.
2. Faith in God satisfies these needs.
3. Therefore, we are justified in having faith in God.

The Evidential Argument

This says that having these needs that only God can satisfy is evidence of God’s existence (because all natural explanations of the presence of needs fail). It is an argument about the existence of God, but it doesn’t say anything about whether faith in this God is justified. Again this argument has three steps:

1. We feel these basic human needs.
2. Only God can satisfy these needs.
3. Therefore, God exists.

Williams turns to food to illustrate these two different arguments.

Existential Argument to Justify Eating

1. I am hungry.
2. Eating satisfies hunger.
3. I am justified in eating.

But notice, this argument is not saying anything about the existence of food, at least about food nearby that will satisfy the hunger.

Evidential Argument for the Existence of Food

1. I am hungry.
2. Only food satisfies hunger.
3. Therefore, food exists.

The evidential argument tries to prove the existence of food by showing that food’s existence is needed to explain how people get hungry for food. It’s a claim that food exists but not that we should eat.

Before returning to the existential argument that justifies having faith in God, Williams looks more closely at the evidential argument, the argument that attempts to prove God’s existence or Christianity’s veracity based upon the evidence of needs we find in people.

A Closer Look at the Evidential Argument

First, the evidential argument says that the only explanation for the needs that we feel is that God created us with them. Attempted natural explanations of many of these needs fail. For example, neither evolution, Freud, psychology, or biology can explain the need to experience awe.

Second, Christianity correctly describes human needs. As the needs that Christianity says exist and claims to supply match the needs people do actually possess, we can conclude that Christianity is true or at least partly true. Blaise Pascal, for example, argued that Christianity alone accounts for both the greatness and wretchedness of man. He exclaimed:

“How novel, how monstrous, how chaotic, how paradoxical, how prodigious! Judge of all things, feeble earthworm, repository of truth, sink of doubt and error, glory and refuse of the universe!”

Christianity’s perfect description of this dueling dual nature in humanity supports the truthfulness of Christianity.

Third, Christianity does not just describe our needs but claims to meet them, and actually does meet them, as we often see. Christianity, therefore, gives an accurate account of reality.

Same Needs, Different Argument

As you can see, both the existential and evidential arguments claim that Christian faith satisfies many basic needs. The evidential argument uses this to make a case for believing the Christian faith is true. The existential argument is not making a claim about truth or theism. It’s simply saying that if such a faith satisfies need, you are justified in having that faith.

The person convinced by the existential argument says, “I believe because it satisfies my needs.” The person convinced by the evidential argument says “I believe because the Christian faith is true.” To further highlight the essential difference between these arguments, Williams points to British philosopher Richard Swinburne who illustrated how people believe certain non-religious things based upon need:

  • The mother who has to believe that her missing son is alive or else she will to go to pieces psychologically.
  • The husband who has to believe that his wife is faithful if he is to avoid mistreating her.
  • The lawyer who has to believe that his client is innocent if he is to make a good speech in his defense.

None of these people rely on evidence for their “faith”; they believe to avoid certain painful feelings or to enjoy certain positive feelings.

After giving three examples of writers who have used evidential arguments based upon need, Ernest Becker (Denial of Death), N. T. Wright (Simply Christian), and C. S Lewis (Mere Christianity), Williams points out that, in each of these cases, the evidential argument points to the presence of needs as a fact that needs explaining, whereas the existential argument doesn’t try to explain why there are needs but simply uses them to move one to faith.

Blaise Pascal

Despite the common focus on needs in both the existential and evidential argument, Williams claims Blaise Pascal is one of the few apologists who has used existential and evidential arguments to persuade people to become Christians. We’ll take a closer look at him in the next post.