Many people wonder how one can believe in God in the 21st century. The same question was asked in previous centuries, too. Believers, on the other hand, can ask non-believers the same question: how can one not believe in God given that it is impossible to prove God’s non-existence rationally and logically. Nevertheless, our opponents demand rational arguments in favor of our point of view. Sadly, Christians cannot provide such arguments sometimes. We are so accustomed to the idea that God exists that we stop thinking about our faith; hence, we cannot maintain a healthy dialog about it. Here are five rational arguments to help every Christian to discuss the existence of God with atheists or agnostics.
1. Cosmological argument (Greek Kosmos, lit. order, universe). It is one of the most ancient arguments in favor of the existence of God. The history of this argument goes back to Aristotle (†322 BC), Plato (†347 BC), and other philosophers. Its basic premise is the concept of causality. Everything or almost everything in the world has a cause, an origin. Nevertheless, this chain of causation is finite, i.e., there must be the first cause, which is the source of all things. The first cause has to have the cause of its own existence in itself. This is the perfect and absolute Being who gave birth to the world, and we call him God.
2. Teleological argument (Greek Teleo, lit. finish, make perfect). One of the most ancient yet a very simple and convincing argument, which essentially boils down to the observed intelligent design of the world both in general and in its parts. The smart design of the world leads us to think of a sentient and powerful Being who created this world or set it in motion.
L.S.Berg, a prominent Soviet scientist (†1950), put it aptly, “The basic premise, which a researcher uses to understand the laws of nature, is that nature has laws, that it is fathomable and knowable; that there is a pre-established harmony between the laws of thinking and the laws of nature. Unless we make this assumption, true scientific exploration is impossible.” (L.S. Berg, The Theory of Evolution. Petrograd, 1922, pp. 67-68). Hence, science is based on the assumption of intelligent design of our world.
3. Ontological argument. It was first introduced by Anselm of Canterbury (†1109); however, some authors claim that Plotinus (†270) was the first to come up with that argument. It sounds weird and unusual but it has withstood scrutiny and criticism by many notable philosophers. Not everyone accepts this argument but it has become an integral part of the history of philosophy and religion. Here is how it goes: God is the all-perfect Being, the Ideal One. If we have this concept of a perfect Being in our brains, this Being can’t be non-existent because otherwise it wouldn’t be perfect. Non-existence is an imperfection, after all. Given that the non-existence of the Absolute Being is logically impossible, then it necessarily exists, and therefore there is a God. It is useful both for proving God’s existence and for improving your logical thinking skills.
4. Kantian argument from morality. The first premise of Immanuel Kant (†1804): The universe is subject to the law of causation. All events are tied to each other by cause and effect. One phenomenon or object exerts influence on the other. This is the fundamental law of nature. The second premise: If we humans are totally subject to the same law, then we cannot be held morally responsible for our actions because they are a mere effect of a chain of events and not a matter of our free choice. The third premise is: If we postulate moral responsibility of humans, which we have to do, we are led to admit that humans are free from the main law of the Universe. Conclusion: while we live in a cause-and-effect world, we are free to do what we choose to do. We have the experience of the existence in which laws of liberty, love, and reason prevail over blunt determinism. This kind of existence is called God in philosophers’ lingo.
5. Argument from religious experience. This argument is based on observed existence of religious experiences among people of all ages, occupations, and ethnic backgrounds throughout the history. Many a great scientist have had religious experiences, or a unique sensation of God’s presence. If all humans share an innate attraction to religion, there must be the object of religion, or better still, the One who kindles this thirst for the sacred, the thirst for the Living God.
In the end, there is no empirical way to prove the non-existence of God. On the contrary, there is an empirical way to check whether God really exists, and it was suggested by the Savior, Blessed are the pure in heart: for they shall see God (Matthew 5:8). Cleanse your heart, and you shall see God. You shall know for a fact that He exists because there will be nothing that could block his Light from your view. The arguments we have listed here are great and useful in our discussions with atheists and may help us to bolster our own faith by means of God-given reason. With that said, all those arguments will not help us or those who look for God if they fail to see the light of eternal life in our eyes.