How do we know that God exists? And even if God exists, how do we know what he is like?
This is part three in a four-part series that provides a few foundational arguments for the truth of Christianity. In part one, we examined the life of Jesus and showed that he presents us with a dilemma: we must either reject him as an evil megalomaniac or accept him as our king and rescuer. In part two, we looked in more detail at one important reason to accept Jesus’ claims: his resurrection. To quote the late non-Christian philosopher Antony Flew, “the evidence for the Resurrection is better than for claimed miracles in any other religion. It is outstanding in both quality and quantity.” In this third essay, I’d like to look at a whole array of arguments drawn from natural theology, the study of the knowledge of God that we have from nature and experience.
I’d like to quickly examine four different arguments: the success of mathematics, the cosmological argument, the argument from fine-tuning, and the moral argument. One important preface to this entire discussion is that, in my opinion, these arguments should not be viewed as ‘proofs’ of God but as ‘evidence’ for God. Why? Because ‘proof’ is generally relegated to the field of mathematics. Speaking as a professional scientist myself, I can attest that scientists rarely demand ‘proof’ that theories are true. Instead, scientists and those in many other fields such as economics, medicine, and archaeology seek the best explanation for the evidence that they have. When considering arguments for God’s existence, we should not demand ‘proof’ but should instead ask ourselves “Which worldview is the best explanation of the evidence provided?” After looking at these four arguments, I’ll then discuss the issue of God’s special revelation and its role in our lives and in our evangelism.
Evidence for God’s existence
First, the success of mathematics in the physical sciences is extremely surprising. Nobel Prize-winning physicist Eugene Wigner wrote an article over fifty years ago in which he repeatedly used the words ‘miracle’ and ‘miraculous’ to describe two phenomena: 1) the fact that nature is so uniformly described by mathematics and 2) the fact that human beings can comprehend this mathematical uniformity. After all, why do the same, beautiful mathematical equations seem to apply uniformly across all time and space? We could easily imagine a universe that was haphazard and chaotic, in which the laws of nature varied from time to time and from place to place. And why are human beings alone able to discern, comprehend, and marvel at these deep physical laws? Chimpanzees and dolphins are both highly intelligent; yet their capacity for abstract thought is nowhere close to that of an average human being. An atheist might object that evolution selects for intelligence, leading to our highly developed cognitive abilities. And, certainly, organisms which do not have the intelligence to avoid saber-toothed tigers or high cliffs would quickly die off. But why would evolution provide nomadic hunter-gatherers the mental capacity to understand quantum mechanics? Or topology? Surely, these abilities are far, far beyond what would be needed for survival and reproduction.
Both of these phenomena remain puzzling if God does not exist. But if God exists and created man and woman in His image, then these facts are not puzzling at all. The beauty and rationality of the Creation is merely a reflection of the beauty and rationality of the Creator. Man himself was uniquely made in the divine image with the capacity to comprehend and marvel at all that He had made.
Second, the origin and existence of the universe raise interesting questions. The vast majority of modern physicists believe that the universe had a beginning in the finite past in an event known as the Big Bang. What is not as well-known is the fact that, prior to the advent of the Big Bang theory, most scientists believed that the universe had existed eternally. Furthermore, many scientists resisted the Big Bang for decades, believing that it was too close to creationism. As recently as 1989, John Maddox -the editor of Nature magazine- wrote that the Big Bang was “philosophically unacceptable” and that “creationists and those of similar persuasion seeking support for their opinions have ample justification in the doctrine of the Big Bang” [Nature, 340, (1989), p. 425]. The reason for his frustration is apparent: if the universe had existed eternally, it would have needed no cause. But if the universe came into being in the finite past, then what caused it to come into being? Also, even apart from asking “what caused the universe to begin to exist?”, we can ask “why does something exist rather than nothing at all?” All of us can conceive of nothing existing at all: no people, no stars, no planets, no atoms. So why does the universe exist? To put it another way, what explains the universe’s existence?
If God does not exist, both of these questions are difficult to answer. Perhaps the Big Bang theory is wrong and the universe did not begin to exist, or the universe caused itself to exist, or the universe does not require a cause? Perhaps the universe is just a brute fact that needs no explanation or the universe explains its own existence? These are possibilities open to an atheist, but they are problematic. For instance, apart from its problematic implications, does the skeptic have any evidence that leads him to the reject the Big Bang? Or can we really be satisfied with the assertion that the universe is a ‘brute fact’ that needs no explanation? On the other hand, if God does exist, then we have clear answers to both of these questions. According to the Bible, God is eternal and uncaused and brought the universe into being. Moreover, God’s choice to create explains why the universe exists. God’s existence does not need to be explained by something external to Himself because He is self-existent; He does not depend on anything for His existence but is instead the reason for the existence of everything else (see Acts. 17:24-25).
Third, the recently discovered fine-tuning of the universe has provided even more suggestive evidence. The standard model of physics, which is currently our best working model for the interaction of fundamental forces and subatomic particles, includes a number of independent parameters that must be obtained from an experiment. What physicists have recently discovered is that life would be impossible if some of these constants had been changed even a fraction of a percent. The most dramatic example of fine tuning is found in the cosmological constant, which is finely tuned to one part in one trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion. Fine-tuning is now widely recognized by both Christian and non-Christian physicists to be a real phenomenon and led renowned British astrophysicist Fred Hoyle to remark: “A common sense interpretation of the facts suggests that a super intellect has monkeyed with physics, as well as with chemistry and biology, and that there are no blind forces worth speaking about in nature.”
To explain this fine-tuning, many atheists posit the existence of an infinite number of undetectable parallel universes. In each parallel universe, the fundamental constants are all slightly different such that every possible value for the constants is sampled somewhere in the infinite multiverse. We live in the one universe in which life is possible. While there are physical objections to this explanation, a reflection on its implications are particularly astonishing. If an infinite multiverse actually exists, then there are actual universes in which pink unicorns exist or which are composed entirely of Gorgonzola cheese. Those implications alone are enough to make most people hesitate to embrace multiverse theory.
On the other hand, if God exists, created the universe and designed it to be habitable by embodied creatures like ourselves, it is not surprising to find it finely-tuned to support life.
Finally, the existence of objective moral facts and obligations needs to be explained. Objective moral facts are propositions about good and evil that are independent of human beliefs. Just as physical facts like ‘the Earth orbits the sun’ are true regardless of whether anyone affirms them, objective moral facts are statements like ‘torturing children for pleasure is evil’ which are true independent of whether people affirm them. Moral obligations are duties like ‘You should love your neighbor’ that are binding on us regardless of whether we acknowledge them.
Some atheists choose to deny that objective moral facts and duties exist. There are numerous responses to this position, but the most straightforward one is that few if any people actually live a life consistent with moral relativism. For instance, a consistent moral relativist should not protest the immoral practices of other cultures, or demand justice for oppressed and marginalized groups in today’s society, or condemn God’s actions in the Bible as ‘immoral.’ All of these activities assume that there is some objective standard of morality to which we can hold other people and even God accountable. But if moral relativism is true, then no such standard exists. Moreover, no atheist who denies the existence of an objective standard of morality can claim that we are obligated to seek the truth. If neither knowledge of the truth nor ignorance is intrinsically good, on what basis does the moral relativist demand that you seek to find out whether atheism is true?
Other atheists affirm that objective moral facts and duties exist, but claim that they can be grounded in something other than God. Philosophers vary widely regarding how this can be accomplished, but all atheistic theories of morality face two significant problems: 1) they require that human beings have intrinsic value such that actions which harm humans are wrong. But if we are merely “accidental collocations of atoms”, why would we have any more intrinsic value than any other “accidental collocation of atoms” like a rock or a tree? 2) they require us to explain why moral obligation exists such that we have certain moral duties like ‘love your neighbor’ or ‘do not murder.’ If there is no perfectly good, loving moral authority to issue these moral commands, then where do they come from? For these reasons and others, many philosophers conclude with atheist Kai Nielsen: “We have not been able to show that reason requires the moral point of view… Reason doesn’t decide here. The picture I have painted for you is not a pleasant one. Reflection on it depresses me… Pure practical reason, even with a good knowledge of the facts, will not take you to morality.”
On the other hand, God’s existence does provide an explanation for the existence of both moral values and duties. Because God is perfectly loving, merciful, and just, His character provides a grounding for moral values. His commands to us like ‘love God with your whole heart’, ‘love your neighbor’, and ‘seek knowledge and understanding’ constitute our moral duties.
In summary, I’ve chosen four pieces of evidence that I believe point to God’s existence: the applicability of mathematics to nature, the origin and existence of the universe, the fine-tuning of the fundamental constants of physics, and the existence of objective moral facts. The question before us is whether atheism or theism provides a better explanation for the evidence. Although atheistic responses to each of these pieces of evidence exist, in no case do I think that atheism provides as plausible an answer as theism. Indeed, many atheists acknowledge that these phenomena are currently inexplicable, even if they hold out hope that science or philosophy will one day be able to provide a better explanation. However, unlike the majority of scientific and philosophical issues, our belief in God’s existence has a profound and immediate impact on our lives. While we may genuinely desire more time to explore questions that we’ve never before considered, we need to recognize that any deferred decision is an implicit ‘no’ to God’s authority over us and His offer of salvation to us. At the very least, agnostics and others who are skeptical of Christianity should begin to grapple seriously with the pieces of evidence presented above and should genuinely consider whether the Christian worldview provides better answers than those afforded by atheism.
There are two final points to make with regards to our discussion so far.
Frist, one major obstacle to any discussion of God’s existence is the demand that Christians ‘prove that God exists’ because ‘extraordinary claims require extraordinary evidence.’ While much can be said about this demand, one observation is especially crucial. Instead of asking the question “Is Christianity true?”, skeptics are often really asking the question: “Is the evidence you present so unbearably strong that it will force me to believe in Christianity against my will?” That is a dangerous approach. A reflection on the enormous implications of God’s existence should make us reexamine the motivation behind our questions. Furthermore, the very notion of ‘extraordinary evidence’ is extremely subjective. As a Christian, I consider the existence of the multiverse or claims of moral relativism to be extraordinary. Yet few skeptics seem to think that they are required to provide evidence, let alone extraordinary evidence, for either of these claims. Since Christianity entails an entire worldview with its own plausibility structure, atheists should be willing to ‘step inside’ the Christian worldview to see whether it makes more sense of reality than their own worldview.
Second, Christians should remember that while arguments from natural theology can provide strong support for our claim that God exists, they are neither necessary nor sufficient for personal knowledge of God. If arguments from natural theology or any other discipline were required in order to know God, then people who had never heard of or reflected on such arguments would be unable to know God. But, obviously, God desires to be known not just by professional philosophers and 21st century scientists, but by children and 6th century peasants. And while natural theology can tell us generally about God’s existence and attributes, it cannot give us specific information: Does God love us? What does he require of us? Does he interact with human history? Does he answer prayer? To answer these questions, we need more than just God’s general revelation in nature; we need his special revelation in Scripture. It is in the Bible that God definitively tells us who He is and what He is like. Scripture is sufficient for us to have personal knowledge of God and it is primarily through Scripture that God makes himself known and has made himself known to people throughout history.
To illustrate this point, imagine that you were walking through the halls of some beautiful building. From your observations alone, you might be able to infer a great deal about the architect: he is a man of great intelligence, ingenuity, and love of beauty. But imagine that the architect tapped you on the shoulder and began speaking to you. Now you would have definitive and detailed access to this man’s character. You could have a personal relationship with him in a way that would be impossible from staring at his work alone. The same is true of God. While we can learn about Him and praise him for His works, it is His words that make it possible for us to know him personally. We must always go beyond natural theology to a proclamation of the gospel. God’s power and glory are made known to all people by what He has created, but His love, mercy and message of salvation are made known to us in the gospel of Jesus Christ.
Craig-Krauss debate – A debate between Christian philosopher Dr. William Lane Craig and atheist astrophysicist Dr. Lawrence Krauss on whether there is evidence for God’s existence.
Does God exist and why does it matter? – A forty-minute presentation to Duke’s Intervarsity Christian fellowship.