People have argued about God for thousands of years. Some arguments say the universe needs a maker, or that right and wrong need a God. Other arguments ask: if a loving, all-powerful God exists, why is there so much suffering, and why doesn't God make himself obvious? This page explains each argument fairly, in its strongest form, and what the other side says back.
No argument for God has convinced most professional philosophers, and each one faces well-known replies. The strongest arguments against the God of classical theism are the problem of evil and divine hiddenness. None of these debates is "settled"; but the burden of proof stays with the claim that God exists.
Each argument opens to show its steps, its best defense, and the main replies. We state each in the form its defenders would recognize. No straw men. (See Thinking tools.)
Arguments for God
1. The cosmological (Kalam) argument: "the universe needs a cause"
Steps: (1) Whatever begins to exist has a cause. (2) The universe began to exist. (3) So the universe has a cause, and defenders argue it must be timeless, spaceless, powerful and personal.1
Best defense: Something can't come from nothing; the Big Bang shows a beginning.
Main replies: Our idea of "cause" comes from events inside time; whether it applies to the whole universe is unknown. Physics doesn't say the universe came from nothing or that nothing came before. And even a "first cause" isn't shown to be a person, let alone a particular god.2 Full page: The Big Bang.
2. The design and fine-tuning argument: "the universe is set up for life"
Steps: Some constants of physics seem to fall in narrow life-permitting ranges; this is far more likely if a designer chose them than by chance; so a designer probably exists.
Best defense: Philosophers Hawthorne and Isaacs argue the argument is "legitimate" and that common objections misunderstand it.3
Main replies: We don't know the range of possible constants or their probabilities; life might be possible in other forms; most of the universe is hostile to life; and the "designer" would itself need explaining.4 Full page: Fine-tuning.
3. The moral argument: "real right and wrong need God"
Steps: (1) If God doesn't exist, objective moral values don't exist. (2) Objective moral values do exist. (3) So God exists.
Best defense: We're more sure that torturing children for fun is wrong than of any theory that would deny it.
Main replies: The Euthyphro dilemma: if God's commands make things good, goodness is arbitrary; if God commands things because they're good, goodness doesn't depend on God. Many secular philosophers ground morality in the wellbeing of feeling creatures. And biblical laws like Deuteronomy 22 are judged by moral standards we hold independently. Full page: Morality.
4. The ontological argument: "God's definition proves God exists"
Steps: God is "that than which nothing greater can be conceived." Existing in reality is greater than existing only in the mind. So God must exist in reality.
Main replies: A monk named Gaunilo replied that the same logic would prove a "greatest possible island" exists. Kant argued that "existence" isn't a property that makes something greater. Most philosophers, including many believers, don't find it persuasive.
5. Religious experience: "I have felt God's presence"
Best defense: We generally trust our experiences unless we have reason not to; millions report experiences of God.
Main replies: People of every religion report experiences confirming their religion, often contradicting each other. Experiences of a presence can be produced by brain states, fatigue, expectation and group settings. A personal experience can be meaningful without being evidence others should accept.
6. The resurrection: "the empty tomb and the disciples' conviction"
Best defense: The disciples sincerely believed they saw Jesus alive, and were willing to suffer for it.
Main replies: Our sources are anonymous gospels written 40–65 years later that disagree in their details (see Verses that disagree). Sincere belief doesn't show the belief is true; members of many movements have died for contradictory beliefs. Natural explanations, such as grief visions or legend growing over decades, don't require suspending natural laws.
7. Pascal's wager: "believing is the safer bet"
Steps: If you believe and God exists, you gain infinitely; if you don't, you might lose infinitely; so believe.
Main replies: Which god? Many religions threaten nonbelievers, and they can't all be satisfied. Belief can't be switched on by choice. And a God who rewards calculated pretend-belief seems odd.
Arguments against God
1. The problem of evil: "why so much suffering?"
The logical version: An all-powerful, all-knowing, all-good God would prevent pointless suffering. Pointless suffering exists. So such a God doesn't exist.
The evidential version: Even if God could have reasons for some suffering, the sheer amount (children with cancer, animals suffering for hundreds of millions of years before humans existed) makes such a God unlikely.
Best replies: The free-will defense: a world with real freedom is worth the risk of evil. Soul-making: suffering builds virtues. Skeptical theism: we can't expect to understand God's reasons.
Counter-replies: Free will doesn't explain earthquakes, disease or animal suffering. And "we can't know God's reasons" cuts both ways: it also undermines claims to know God is good or what God wants.
2. Divine hiddenness: "why doesn't God show up?"
Philosopher J. L. Schellenberg's argument, in simplified form:5
- If a perfectly loving God exists, God is always open to a personal relationship with anyone capable of one.
- A relationship requires believing God exists.
- So no one open to God would ever fail to believe through no fault of their own.
- But some people do: sincere seekers who are not resisting God, yet don't believe.
- So a perfectly loving God doesn't exist.
Best replies: God may have reasons: protecting free choice, letting faith grow, avoiding forced belief. Some argue relationship doesn't strictly require belief, or that truly nonresistant nonbelievers are rare.5
Counter-reply: Many former believers describe praying sincerely for years and hearing nothing. A loving parent doesn't hide from their children to protect their freedom.
3. Religious diversity: "which one?"
Thousands of religions make incompatible claims, and people mostly hold the religion of the family and culture they were born into. If one were true and important, we'd expect it to be clearer. (Careful: where a belief came from doesn't by itself show it's false; see the genetic fallacy in Thinking tools.)
4. The track record of natural explanations
Again and again, things once explained by gods (lightning, disease, the motions of the planets, the diversity of life) turned out to have natural explanations. The reverse has essentially never happened. That doesn't prove the remaining questions will go the same way, but it's a strong pattern. See How science works.
Meaning without God
"If there's no God, what's the point?" is one of the most common questions, and it deserves a real answer.
- Meaning is made, not found. Relationships, curiosity, creating things, reducing suffering, and enjoying life are meaningful because they matter to us and to others, not because they're assigned from outside.
- A finite life can be precious because it's finite. The ancient philosopher Epicurus argued that death is nothing to fear: "where death is, I am not."
- Morality doesn't vanish. Suffering hurts whether or not a god notices. See Morality.
Believers argue that without God, meaning is only "subjective," a story we tell ourselves, and that a universe that ends in heat death makes all achievements ultimately pointless. Atheists answer that "ultimate" meaning isn't required for real meaning, the same way a song doesn't need to last forever to be worth hearing, and that whether a belief is comforting doesn't make it true (the appeal to consequences).
Sources
- Reasonable Faith (William Lane Craig), Debate on the Kalam argument.
- Cambridge University Press, "Kalam cosmological arguments for atheism", The Cambridge Companion to Atheism.
- Hawthorne & Isaacs, Misapprehensions about the fine-tuning argument (2017).
- Colyvan, Garfield & Priest, Problems with the argument from fine tuning, Synthese (2005).
- Stanford Encyclopedia of Philosophy, Hiddenness of God: Schellenberg's argument (1993 and later versions) and theistic responses.
- Marked for a second source: the ontological argument history (Anselm, Gaunilo, Kant), the logical/evidential problem-of-evil summary and its replies, and the Epicurus quotation are standard philosophy; individual citations still to be added.