Christianity is not based upon a single argument. There is no mathematical equation that proves Christianity in the same way that we can prove a theorem in geometry, and I am always a little suspicious when someone claims to have found an argument that no reasonable person could possibly reject. People are quite capable of disagreeing about evidence, particularly when the subject involves questions as large as God, miracles, and the meaning of human existence. The case for Christianity is better understood as a cumulative case. We begin with the world in which we actually live and ask which explanation makes the best sense of it. Why does anything exist? Why is the universe intelligible? Why are human beings capable of rational thought? Are moral values merely preferences, or are some things actually right and wrong? Then we turn from philosophy to history and ask what happened in first-century Judea and, particularly, what we should make of Jesus of Nazareth.
Christianity makes claims in both areas. It claims that the universe exists because God created it and that human beings possess unique value because they were created in His image. It also claims that God acted within history through Jesus Christ, who was crucified and subsequently raised from the dead. The Christian case therefore cannot be reduced either to abstract philosophy or to historical investigation alone. Christianity presents a worldview and makes historical claims within that worldview. The question is whether those claims fit together and whether they provide a reasonable explanation of the evidence available to us.
Evidence and Proof
Before examining the evidence, it helps to distinguish evidence from proof. We often demand “proof” for religious claims while accepting conclusions in most other areas of life on the basis of evidence. Courts examine testimony, documents, physical evidence, motives, and competing explanations. Historians examine written sources, archaeological discoveries, cultural context, and the relationship between independent accounts. Scientists develop explanations that account for observations and then test those explanations against additional evidence. In each case we reason from evidence toward the explanation that appears to account for it best.
Christian claims can be investigated in much the same way. Some evidence is philosophical, some historical, some textual, and some experiential. Not every piece of evidence carries equal weight, and not every argument points uniquely to Christianity. An argument for the existence of God, for example, might provide evidence for theism without telling us whether Christianity, Judaism, or Islam is true. Establishing that distinction is important. We should not claim that an argument proves more than it actually does. The case becomes specifically Christian when the broader evidence for God is combined with the historical claims concerning Jesus.
Does the Universe Point to God?
The existence of the universe raises one of the most basic questions human beings can ask: Why is there something rather than nothing? Everything we encounter within ordinary experience appears to depend upon something else for its existence. Christians have traditionally argued that the chain of explanation cannot continue indefinitely without eventually reaching something that does not derive its existence from anything else. Christianity identifies that necessary reality as God. Critics have proposed alternatives, including an eternal universe, an eternal physical reality underlying our universe, or the possibility that existence simply has no ultimate explanation. The debate is philosophical, but the question does not disappear merely because God is removed from the proposed answer.
Modern cosmology has added another dimension to the discussion. The universe appears to have developed from an extraordinarily hot and dense early state and possesses physical laws and constants that permit complex matter and life to exist. The apparent fine-tuning of those conditions has generated considerable philosophical debate. Some regard fine-tuning as evidence of design, while others appeal to selection effects, a multiverse, or physical principles not yet understood. Christians should be careful not to turn gaps in scientific knowledge into arguments for God. At the same time, scientific descriptions of how the universe developed do not by themselves answer the philosophical question of why a universe governed by intelligible laws exists at all. Science and theology may address different aspects of the same reality.
The Intelligibility of the World
One of the remarkable features of the universe is that it can be understood. Human beings living on a small planet can describe the motions of distant galaxies, discover mathematical relationships governing physical phenomena, reconstruct events that occurred billions of years ago, and manipulate nature according to principles discovered through rational investigation. We tend to take this for granted because science has been so successful, but the correspondence between the human mind and the structure of the universe is itself worth thinking about.
Christianity offers a natural explanation for that correspondence. If the universe is the creation of a rational God and human beings were created with minds capable of understanding His creation, it is not surprising that rational investigation works. Naturalism can also account for much of our cognitive ability through evolution, since organisms capable of accurately navigating their environment possess obvious survival advantages. The interesting question is whether survival alone adequately explains our ability to reason about abstract mathematics, cosmology, logic, metaphysics, and realities far removed from the environment in which human cognition developed. This does not prove Christianity, but it forms another part of the larger question concerning which worldview makes the best sense of the world we encounter.
Morality and Human Value
Most people live as though some things really are wrong. Torturing a child for amusement would not become morally acceptable even if a society voted unanimously to approve it. Christians argue that objective moral values make sense if goodness is grounded ultimately in the character of God and human beings possess intrinsic worth because they bear His image. The moral argument does not claim that atheists cannot be moral. Clearly they can, and religious people are quite capable of behaving immorally. The issue is not who behaves better but what provides the foundation for genuine moral obligation and human worth.
Naturalistic philosophers have proposed sophisticated accounts of morality based upon reason, human flourishing, social cooperation, evolution, or objective moral facts that do not depend upon God. Those proposals deserve serious consideration. Christianity nevertheless offers an integrated explanation in which human dignity and moral obligation are connected to what human beings actually are rather than merely to what individuals or societies happen to prefer. Again, this does not establish the truth of Christianity by itself. It contributes to the cumulative case.
From God to Jesus
Even if we concluded that there are good reasons to believe God exists, we would still have a long way to go before establishing Christianity. Christianity ultimately rests upon claims about a particular person who lived in a particular place at a particular time. Jesus of Nazareth was not presented by the earliest Christians merely as a teacher whose philosophy they found inspiring. They claimed that God had acted decisively through Him and that His death and resurrection had changed the course of human history.
The existence of Jesus and His crucifixion under Pontius Pilate belong to the ordinary territory of ancient history. The real controversy begins when we ask what happened afterward. The New Testament claims that Jesus’ followers came to believe that He had risen bodily from the dead and that they encountered Him alive after His crucifixion. Paul preserves an early summary of this proclamation in 1 Corinthians 15:3–8, where he refers to Jesus’ death, burial, resurrection, and appearances to individuals and groups. Whatever explanation one eventually accepts, the rise of the Christian resurrection proclamation requires historical explanation.
The Resurrection
The resurrection is where the Christian case becomes unmistakably Christian. Paul himself recognized the stakes when he wrote that if Christ had not been raised, Christian faith was futile (1 Corinthians 15:14–17). Christianity does not merely claim that Jesus’ teachings survived His death or that His followers experienced a renewed sense of hope. It claims that the man who had been crucified was raised from the dead.
Historians can investigate the sources, the beliefs of the earliest disciples, Paul’s conversion, the conversion of James, traditions concerning the empty tomb, and the rapid emergence of resurrection proclamation within the earliest Christian movement. Historians cannot reproduce the resurrection in a laboratory, and disagreement remains over what conclusions historical methods can legitimately reach concerning miraculous events. Skeptics have proposed alternative explanations involving visions, legendary development, mistaken experiences, or combinations of natural factors. Christians argue that the bodily resurrection provides the best explanation of the evidence. The issue should not be settled simply by assuming beforehand either that miracles happen or that miracles are impossible. The evidence and competing explanations need to be examined.
Can We Trust the Sources?
Any historical case for Jesus depends heavily upon ancient documents, particularly the New Testament. That immediately raises questions about reliability. How early are the sources? Were the Gospel traditions preserved accurately? Have the biblical manuscripts been transmitted reliably? Are there contradictions between the accounts? Did later Christians change the story as Christianity developed?
These are legitimate historical questions, and Christianity does not need to avoid them. The New Testament is unusually well represented in the manuscript record compared with most works of antiquity, although having many manuscripts does not automatically establish that every event described in them occurred. Textual criticism helps us determine what the authors originally wrote; historical analysis asks whether what they wrote is credible. Those are related but distinct questions. The Gospels should therefore be examined as ancient historical sources rather than either accepted uncritically because they are Scripture or dismissed automatically because they contain supernatural claims.
Archaeology and non-Christian historical sources can also illuminate the world described in the New Testament. They cannot prove the theological claims of Christianity, but they can confirm people, places, institutions, customs, and historical circumstances. At other times archaeological evidence may force us to reconsider an interpretation or acknowledge uncertainty. Good apologetics should welcome both outcomes. If Christianity is historically grounded, careful historical investigation should be an ally rather than an enemy.
What About Religious Experience?
Millions of Christians throughout history have claimed experiences that they understand as encounters with God. Prayer, conversion, answered prayer, healing, guidance, and a profound awareness of God’s presence have played important roles in Christian belief. Such experiences should not simply be dismissed, but neither should they be treated as unquestionable proof. Followers of other religions also report powerful religious experiences, and psychological explanations can account for at least some experiences that people interpret spiritually.
Personal experience is therefore part of the evidence, but it needs interpretation. A Christian may have very good personal reasons for believing that God has acted in his life while recognizing that the experience alone may not persuade someone else. Christianity does not rest entirely upon private religious experience. Its central claims concern events that Christians believe occurred publicly in history, particularly the life, death, and resurrection of Jesus.
What Would Count Against Christianity?
A worldview that explains everything regardless of what happens does not explain very much. Christianity makes claims that expose it to investigation. Paul provided the clearest example: if Christ has not been raised, Christian faith is false. That is a remarkable admission for one of Christianity’s earliest missionaries. He did not say that Christianity would remain spiritually meaningful even if the resurrection never happened. He tied the truth of the faith to an event he believed actually occurred.
Christians should therefore resist the temptation to protect Christianity from every difficult question. Apparent contradictions in Scripture should be examined rather than waved away. Historical objections should be investigated. Scientific discoveries should be understood rather than feared. Philosophical challenges should be answered as well as we can, and when we do not know an answer, there is nothing wrong with saying so. Confidence in Christianity should not require pretending that every question is easy.
The Cumulative Case
No single argument presented here establishes Christianity by itself. That is precisely why the cumulative approach is important. The existence and apparent contingency of the universe, its intelligibility, consciousness, reason, morality, human dignity, the historical person of Jesus, the reliability of the relevant sources, the origin of the resurrection proclamation, and religious experience form different pieces of a much larger picture. Some pieces are stronger than others, and reasonable people can assign them different weights.
The Christian claim is that these pieces fit together. The God proposed by philosophical arguments is not left as an abstract first cause. Christianity claims that this God has acted within history and revealed Himself most fully in Jesus Christ. The historical case for Jesus, in turn, exists within a worldview in which the resurrection is not an arbitrary violation of nature but an act of the God who created nature in the first place. Philosophy and history meet at that point.
Christianity does not ask people to believe without evidence, nor does it promise the kind of certainty that eliminates every possible objection. It asks us to consider the evidence, compare competing explanations, and determine which worldview makes the best sense of reality as a whole. That is a much larger task than finding one argument that supposedly proves God exists, but it is also a much stronger foundation for faith.