How to Prove God Exists
Can we prove God exists? How? God is all about absolutes. He lives in a world that is beyond us—a world of spirit and light. How can we ever prove that He exists?
What does it mean to prove something exists? Is it enough to believe something is true? According to Joseph Goebbels, Hitler’s propaganda minister, “If you repeat a lie often enough, people will believe it, and you will even come to believe it yourself.” There is some question Goebbels ever said that but this statement was widespread in America during the 1990s.
According to that quote, if I repeat a lie often enough, people will believe it. Does this apply to God? Atheists say it does. Some atheists say God was invented by the ruling class to keep the common people under their control. Is that true?
What is the basis for our belief in God? Is it a convenient lie or can the existence of God be proven? What is the truth? How can we find truth?
Francis Bacon, an early scientist, described two ways to discover truth. These ways are known to us as inductive and deductive reasoning.
There are and can be only two ways of searching into and discovering truth. The one [deductive reasoning] flies from the senses and particulars to the most general axioms, and from these principles, the truth of which it takes for settled and immovable, proceeds to judgment and to the discovery of middle axioms. And this way is now in fashion. The other [inductive reasoning] derives axioms from the senses and particulars, rising by a gradual and unbroken ascent, so that it arrives at the most general axioms last of all. This is the true way, but as yet untried. “The New Organon” (1620), aphorism XIX
Bacon did not make this up. Philosophy has depended on these two forms of reasoning for at least two millennia. Let’s take a deeper look at inductive and deductive reasoning.
Inductive Reasoning—From the Bottom Up
Inductive reasoning starts with observation. The focus of our observation usually are physical objects. Other subjects are possible. For example, psychologists observe people.
What are they looking for—these people who observe? Usually they try to discover relationships and patterns between the objects being studied.
Let’s find a simple example. Suppose a person in the far north wonders about ice. Where does it come from? Why does ice seem to grow in winter and shrink in summer? He decides to study ice very carefully. Perhaps his observations will help him understand new truths about ice.
So he goes outside one winter day and gets a piece of ice. He brings the ice indoors and sets it next to the fire. A few minutes later he checks on the ice and it is gone. It disappeared! Where did it go? In place of the ice there is a wet spot. From where did the wet spot come?
He brings another piece of ice indoors. But this time he puts it in a bucket. He sets the bucket next to the fire and watches it closely. The ice starts to turn into water before his very eyes. Ha! He discovered something about ice. It’s really just a form of water. But what makes the water become hard? What makes it turn into ice?
Our friend thinks about this transformation. He remembers that the water was ice when it was left in the cold. The ice turned to water when it was next to the fire. He forms a tentative hypothesis. Water turns into ice in cold places. Ice turns into water in warm places.
He tests his hypothesis again and again. It works. Water becomes ice in cold places. Ice becomes water in warm places. He comes up with a theory: ice is frozen water; water is heated ice.
Does this scenario sound familiar to you? This process is used by science to discover new truths about the physical world. It’s called inductive reasoning.
Let’s look at another example—the weather. This example is many times more complicated than frozen water. How do we know when it’s going to rain?
Scientists begin by gathering data. Weather predictions are very complex and depend on a lot of factors. Scientists are going to need mountains of data. They make thousands of observations about the weather. Computers are a huge help in sifting the data.
What conditions are present when it rains? Scientists use measuring devices for better accuracy. They study humidity, wind speed and direction, temperature, barometric pressure, and a multitude of other weather features. Patterns begin to form in the data, such as, “rain occurs more often with rising humidity and falling barometric pressure.” They also notice the presence of clouds during a rain event.
But clouds, rising humidity, and falling barometric pressure do not always result in rain. There are thousands of variables to consider. We said, “rain occurs more often.” What does “more often” mean? From comparing trends in their mountains of data, scientists make their predictions in terms of probabilities. “When the relative humidity is 90% and the barometric pressure falls to 29.5 inches of mercury, the chance of rain is 0.65 (65%).” Of course, I made those numbers up. No weatherman would try to predict the weather from so few variables.
Predicting the weather is not easy. Weather forecasting takes powerful computers, oceans of data, and hundreds of dedicated meteorologists (weather scientists).
Inductive reasoning is a “bottoms up” approach. It starts with very simple observations. Repeated observations start to yield patterns and regularities. From these patterns we can form some simple hypotheses. As our data base grows we can refine our hypotheses and develop theories.
But there is one huge drawback from inductive reasoning. Inductive reasoning can sift the evidence and help us find patterns. It cannot provide proof. Induction only compiles evidence. The evidence yields probabilities. There is no absolute proof from inductive reasoning.
Deductive Reasoning in Science
The other kind of reasoning is called deductive reasoning. Deductive reasoning is an important factor in science and philosophy. But the form and usefulness of deductive reasoning vary from science to philosophy. Let’s look first at science.
Deductive reasoning in science starts with scientific theories, probabilities, facts, or truth claims. The theory is examined and refined through further observation. Let’s return to our example of weather forecasting.
One day our intrepid weather scientist predicts rain. All of the rain-predicting theories are in place. He sets the probability of rain at 90%. The radar indicates rain is coming. Then the rain starts but it’s not rain! It’s snow! What? Why snow instead of rain?
Our meteorologist makes additional observations. He notices the air temperature. It’s cold outside today. Perhaps cold and snow are connected somehow. He makes additional observations and measurements. He confirms his new theory. Snow often occurs when the air temperature is below 32 degrees Fahrenheit.
Deductive reasoning often is called the “top-down approach.” We start with specific theories. From these theories were draw new hypotheses. Through observation and some experimentation we are able to confirm whether the hypotheses are valid.
Sherlock Holmes uses this sort of deduction when solving crimes. Mark Zegarelli explains this in his book Logic for Dummies.
For example, a murder mystery is an exercise in deduction. Typically, the detective begins with a set of possible suspects — for example, the butler, the maid, the business partner, and the widow. By the end of the story, he or she has reduced this set to only one person — for example, “The victim died in the bathtub but was moved to the bed. But, neither woman could have lifted the body, nor could the butler with his war wound. Therefore, the business partner must have committed the crime.” . . .
Logic allows you to reason deductively with confidence. In fact, it’s tailor-made for sifting through a body of factual statements (premises), ruling out plausible but inaccurate statements (invalid conclusions), and getting to the truth (valid conclusions). For this reason, logic and deduction are intimately connected.
Deductive reasoning and logic helps scientists and detectives in their search for truth. How can it help us in our search for God?
Evidence for God is all around us. Nature displays the wonders of God’s Creation. All we have to do is look. We see the hand of God mending broken relationships. Mature Christians dedicate their lives and their money to help others in need. The eyes of faith find evidence of God at work everywhere.
But this is not proof. We need more than evidence. The physical world provides evidence but not proof. God’s work is visible in the physical world but God is not material. God is beyond the physical. He is metaphysical. Proof for a metaphysical Being requires metaphysical tools. And proof must be beyond doubt. We must have certainty that God exists.
The Need for Certainty
Certainty is a philosophical term with a specific meaning. Certainty is awarded to facts that are beyond doubt. Certainty is a level of confidence that is absolute. According to the Wikipedia definition,
Certainty is perfect knowledge that has total security from error, or the mental state of being without doubt. . . . Something is certain only if no skepticism occur. Philosophy seeks this state.
Ludwig Wittgenstein wrote that certainty is beyond knowledge. Imagine, for example, a man says to you, “I know I have a right hand.” This very statement introduces an element of doubt regarding his right hand. Why would he not have a right hand? Is there something wrong with his right hand? According to Wittgenstein,
the concept ‘know’ is analogous to the concepts ‘believe’, ‘surmise’, ‘doubt’, ‘be convinced’ in that the statement “I know…” can’t be a mistake. And if that is so, then there can be an inference from such an utterance to the truth of an assertion. And here the form “I thought I knew” is being overlooked. – But if this latter is inadmissible, then a mistake in the assertion must be logically impossible too. And anyone who is acquainted with the language-game must realize this – an assurance from a reliable man that he knows cannot contribute anything. “On Certainty,” #23
Certainty is the acceptance of a fact without doubt. We are certain when we have absolute confidence something is true. We have no doubts. It is a level of confidence that transcends mere knowledge. Voltaire said of certainty, “Doubt is not a pleasant condition, but certainty is absurd.”
Very few statements meet the requirements of certainty. The section of this website titled “Proofs for God” contains some statements of certainty. Many of these statements describe logical necessity. The necessity of eternity and infinity and the absolute requirement for a first cause are expressed as statements of certainty.
But what does this have to do with proof for the existence of God?
Deductive Reasoning in Philosophy
Deductive reasoning is known as “top down” logic. That is, you start with premises (statements) and use reason to come to a conclusion about those statements. If the premises are true and clear (valid) and the rules of deductive logic (sound logic) are followed, the conclusion also is true.
Science uses deductive reasoning to bolster the strength of its theories. In the example above about snow, our meteorologist has theories about the conditions needed for rain to fall. But he observes that snow falls rather than rain when the temperature is cold. This leads him to a hypothesis that snow is a form of frozen rain. He makes formal observations about snow and comes to the conclusion that snow is more likely to fall in the winter when the air temperatures are colder.
This is an example of deductive reasoning in science. Premises take the form of theories. There is no certainty in science because science is built on inductive reasoning. Inductive reasoning provides us with generalizations and not with certainty.
Deductive reasoning in philosophy is far more powerful. Premises in philosophy often consist of logically true statements, such as absolutes and statements that are necessarily true. Here is an often used example:
(1) All men are mortal.
(2) Socrates is a man.
(3) Therefore, Socrates is mortal.
If the premises are true and the logic is sound, the conclusion must be true. However, if the premises are false, the conclusion will be false. For example,
(1) All Greek gods are men.
(2) Aphrodite (the goddess of love) is a Greek god.
(3) Aphrodite is a man.
Anyone who knows about Greek mythology knows the conclusion is false. Here is another example. As you can see, the first premise clearly is false.
(1) All creatures that eat carrots are rabbits.
(2) Several Congressmen eat carrots.
(3) These Congressmen are rabbits.
Although the second premise may be true, the false first premise renders the conclusion false. Congressmen are called a lot of names but seldom are they called rabbits.
Let’s try a more technical example. Imagine infinity. Infinity goes on forever. The length and breadth and height of infinity cannot be measured. Let’s make that our first premise.
(1) Infinity cannot be measured.
Think about our universe. Scientists say they can measure the length and height and breadth of the universe. That will be our second premise.
(2) The universe can be measured.
Therefore, when we put these two premises together we are able to draw a conclusion.
(3) The universe is not infinite—it is finite.
Deductive reasoning validates one of the best known proofs for God—The Kalam Cosmological Argument. The first premise is obvious from logic. Nothing comes from nothing. Everything that begins to exist must have a cause of its existence. The only exceptions are eternal things. Here is the first premise:
(1) Everything that has a beginning of its existence has a cause of its existence;
The most current scientific theories indicate the universe began to exist. Therefore,
(2) The universe has a beginning of its existence; Therefore:
(3) The universe has a cause of its existence.
And, as said by Thomas Aquinas, “We give this cause the name ‘God’.” Deductive reasoning can prove that the existence of God is logical and based on reason.
Faith and Proof
By faith I believe the sun will rise in the east tomorrow morning. But logic proves that God exists. I do not base the existence of God only on faith. The existence of God is based on certainty and logical necessity.
By faith I reach into the light-filled eternity. By faith I lift my eyes and say, “Abba! Father!” Logical certainty tells me God is there. The comfort of God’s love tells me He is reaching back.
We need certainty. We need a place to rest—a starting point that will not shift or move or disappear. God is my certainty. God is my starting point. God is my rock.
Inductive Reasoning chart and Deductive Reasoning in Science chart were inspired by Trochim, William M. The Research Methods Knowledge Base, 2nd Edition. Internet WWW page, at URL: http://www.socialresearchmethods.net/kb (version current as of October 20, 2006).