Arguments on Both Sides
Whether God exists is argued as a matter of evidence — from cause, design, and being in favor, and from the problem of evil against — with each argument weighed on its merits. · 13 min
Few questions are held more tightly than whether there is a God, and few are more often settled by upbringing rather than by thought. Philosophy does something unusual with it: it treats the question as arguable — as a place to lay out reasons, examine them, and weigh which carry force. That is not the same as deciding the answer in advance. Done honestly, it means building the strongest case on each side and refusing to let either one win by default.
Guess before you learn
"God is, by definition, the greatest being that can be conceived. A being that exists is greater than one that does not. So God must exist." What does this argument rest on?
This is the ontological argument, and it appeals to no observation at all — only to what the concept of God is said to contain. Philosophers call such reasoning a priori, as against a posteriori arguments that start from what we observe. If you expected every argument about God to lean on evidence from the world, keep the pencil mark: the arguments differ sharply in what they draw on, and that is the first thing to notice.
There are three classic arguments in favor and one great argument against. The aim here is not to crown a winner. It is to see each argument clearly enough to say where its force lies and where it can be pressed — the same skill you used to find premises and conclusions back in Unit I, now turned on the largest question it can be turned on.
9–12
3–5
People give three main reasons to believe in God. One: something had to start everything. Two: the world looks designed, like a made thing. Three: the very idea of a perfect being seems to include being real. And there is one big reason to doubt: if a good, all-powerful God is real, why is there so much suffering? Each reason is an argument you can weigh, not just a feeling.
6–8
The three arguments have names. The cosmological argument: everything that exists depends on something else, so there must be a first cause that depends on nothing — God. The design (or teleological) argument: the universe shows fine-tuned order, and order like that points to a designer. The ontological argument: God is the greatest conceivable being, and a being that exists is greater than one that does not, so God must exist. Against them stands the problem of evil: a wholly good, all-powerful God would not allow needless suffering, yet needless suffering seems real.
9–12
Each argument has a signature strength and a standard reply. The cosmological argument turns on causation and dependence; critics ask why the first cause must be God, or why the chain cannot run back forever. The design argument grew stronger with fine-tuning and weaker with Darwin, who showed how order can arise without a designer. The ontological argument is a priori; Kant's famous reply is that "existence is not a predicate" — saying a thing exists adds nothing to its greatness.
The problem of evil comes in two strengths. The logical version claims God and any evil are outright contradictory, and most think the free-will defense blunts it. The evidential version grants that some evil fits with God but argues the sheer scale of pointless suffering makes God unlikely — a shift from proof to probability that no single argument ends.
K–2
Some people think a maker made the world. Some look at the pain in it and doubt there is one. Both sides give reasons. We can slow down and listen to the reasons.
You do not have to decide today. You can learn to ask, "What is the reason?" — and then ask whether it is a good one. That is already doing philosophy.
Undergrad
Sharpen each. The strongest cosmological arguments are contingency arguments (Leibniz): by the Principle of Sufficient Reason they infer a necessary being — but the PSR is contestable and may prove too much. Design has migrated from Paley's biological analogy to cosmic fine-tuning, whose live rivals are a multiverse with observation-selection effects, or brute fact. Anselm survives Kant in modal dress; and Rowe's evidential problem of evil rests on a "noseeum" inference from we see no justifying good to there is none.
The theist's repairs are specific. Plantinga's free-will defense answers the logical problem: possibly, God cannot create free creatures who never choose wrongly. Soul-making theodicy (Hick) gives suffering a developmental role. Skeptical theism blocks Rowe's inference by denying we can judge which goods God might secure — buying its reply at the price of wider skepticism. Weighing these trade-offs, not tallying arguments, is the real work.
Postgrad
Rendered formally, the disputes concern the cost of each premise. Leibnizian cosmological arguments stand or fall with a strong PSR; weakening it to avoid modal collapse tends to sever the inference to a necessary ground. Fine-tuning is naturally Bayesian: the evidence favors design only if P(fine-tuning | design) exceeds P(fine-tuning | chance) — where the chance term must be scored against multiverse hypotheses with their own observation-selection corrections.
Plantinga's modal ontological argument trades on S5: if a maximally great being is possible, it exists necessarily in some world, hence in all — so the whole weight falls on the possibility premise, which begs the question. Rowe's evidential argument and its CORNEA critique (Wykstra) turn on whether the inference from inscrutable to pointless evil is licensed. The mature verdict: no argument here is a proof, and the honest question is the direction of the total evidence.
a priori / a posteriori
An a priori argument reasons from concepts alone, needing no observation (the ontological argument). An a posteriori argument starts from what we observe of the world (the cosmological and design arguments).
To weigh an argument you must first state it fairly — as a set of premises leading to a conclusion, with nothing smuggled in. Take the design argument, in the form William Paley gave it: if you found a watch on a heath, its fitted parts would force you to infer a maker; the universe shows order of the same kind. Reconstructing it into clean lines is the move that lets you see exactly which premise a critic like Darwin is denying.
Reconstruct the design argument into premises and a conclusion — the steps fade as you master them
Conclusion: The universe has an intelligent designer.
Premise 1: The universe shows intricate, purpose-fitted order, as a watch's parts are fitted to tell time.
Premise 2: Fitted order of this kind is best explained by design, not by chance.
Order is best explained by a designer; the universe has such order; therefore the universe has a designer — an inference to the best explanation.
Now the case on the other side. The problem of evil is the strongest argument against God, and it is strong precisely because it starts from something no one denies: that the world holds terrible, seemingly pointless suffering. The argument tries to show that such suffering is hard to square with a being who is at once all-powerful, all-knowing, and wholly good. Reconstruct it, and you can see exactly which line a believer must resist.
Why is this true?
Why does the free-will defense answer the logical problem of evil but not the evidential one?
The logical version claims God and any evil are contradictory; showing even one possible good — free creatures who sometimes choose wrongly — removes the contradiction. The evidential version grants that and argues instead that the sheer amount of pointless-looking evil makes God unlikely, which a single possible good does not touch.
The believer has replies, and good ones. The free-will defense argues that a world with genuinely free creatures is worth its risk of wrongdoing. Soul-making theodicy argues that some suffering builds character no easy world could. Skeptical theism argues that we are in no position to judge which goods a God might be securing. Each reply has a cost — the last, for instance, buys its answer by admitting we cannot read God's purposes at all. Weighing those costs, rather than counting arguments, is where an honest verdict is earned.
Notice what this lesson did not do: it did not tell you the answer. What it gave you instead is the ability to hold a fierce question at arm's length — to state each side in its strongest form and locate the exact premise where you part company. That is the philosopher's contribution to a debate everyone already has. Next folio takes the same even-handed method into how a society should share its goods.
Note
The moves here — stating a view charitably, then finding the load-bearing premise — are drilled in the Atelier of Mind, the college's thinking workshop.
Practice — new ink and old, interleaved
1.Recalling folio 2: standardize “Since all triangles have three sides, and this shape is a triangle, this shape has three sides.” List the premises, then the conclusion.
2.In one sentence, state the ontological argument charitably — in the form its defenders actually intend.
3.Interleave, folio 6. The most useful thing to do with a radical skeptical argument is to —
4.State the skeptic's argument in its strongest form, in one or two sentences.
5.Order into standard form: “Whales are mammals, and no fish is a mammal, so no whale is a fish.”
- Whales are mammals.
- No fish is a mammal.
- Therefore, no whale is a fish.
6.Without looking back: what is the difference between a valid argument and a sound one?
A valid argument has a form that guarantees the conclusion if the premises are true. A sound argument is valid and also has premises that are in fact true, so its conclusion must be true.
How close were you? Grade yourself honestly — it sets your review date.
7.Interleave, folio 3. An argument is valid when —
8.Skeptical theism blocks the evidential problem of evil by claiming that —
9.Interleave, folio 2. Put this small argument into premise, premise, conclusion order.
- Whatever begins to exist has a cause.
- The universe began to exist.
- So the universe has a cause.