Lecture: Philosophy of Religion
Lecture script · about 15–20 minutes spoken · Week 9
Opening
Picture someone walking on a beach who kicks something hard in the sand. It's a small brass machine with gears that still turn. Nobody would think the tide built it. Now picture a town after a flood, with families sleeping in a school gym. Someone there asks how a good God could let this happen. Hold both scenes. This lecture grows out of them.
These questions show up far from a philosophy room. A nursing student sitting with a family after a disaster meets the second one. An engineering major asking whether a well-ordered machine must have a maker meets the first.
In Week 2 you learned standard form, validity, and strength. In Week 5 you learned the difference between a priori and a posteriori. In Week 8 you met Pascal's wager. In this lecture I'll use all three. We'll meet the classic arguments for God's existence and the strongest arguments against, each in its best form, and I won't tell you which side wins. Next, in Week 10, we turn to ethics and ask whether morality depends on God.
1. Can reason settle it?
Imagine two friends at a diner, one who believes in God and one who doesn't. Tonight each has to state the other's best argument so well that the other nods. That's the spirit of this whole lecture.
The philosophy of religion is the branch of philosophy that asks whether reason can show that God exists or does not, and how faith relates to reason. Theism is the view that God exists, and classical theism describes God as all-powerful, all-knowing, and wholly good. Atheism is the view that God does not exist. Agnosticism suspends judgment either way.
The course pins 6 standard arguments. Three argue for God's existence, one argues for belief, and two argue against. We'll sort each one with your Week 5 tool: does it start from an idea alone, or from observing the world?
Pause and try this. Someone says testing an argument for God is a way of mocking believers. Is that fair?
Think about the two friends at the diner.
Here's the answer. It isn't fair. Stating an argument at its strongest and checking its premises is a form of respect, whichever side you're on.
2. The ontological argument
Think of the greatest pizza you can imagine. Now imagine that same pizza, real and hot, on the table. Which is greater? Most people say the real one. Hold that thought.
Anselm, in his Proslogion, written about 1077 to 1078, built an argument on it. The ontological argument is an a priori argument that reasons from the idea of a being than which nothing greater can be conceived to the conclusion that such a being exists in reality. Here's the course's reconstruction. God is a being than which nothing greater can be conceived. That being exists at least as an idea. If it existed only as an idea, you could conceive of a greater one: the same being, existing for real. But nothing greater than it can be conceived. So it exists in reality.
That last step denies a consequent, the valid form from Week 2. So, read this way, the argument is valid.
Pause and try this. Is the ontological argument a priori or a posteriori?
Look at where its premises come from.
Here's the answer. It's a priori. Every premise is about an idea and what follows from it; none reports an observation.
3. The island objection
Now picture a travel ad for "the greatest possible island": perfect beaches, perfect weather, perfect fruit. Does the idea prove the island is out there?
That's the famous objection. The greatest-possible-island objection says the same pattern of reasoning would prove that a greatest possible island exists, so something must be wrong with the pattern. Run the island through each step and you seem to prove an island no map shows.
The argument's defenders have a reply. An island has no greatest possible form. However good it is, you can always imagine one more beach. A being than which nothing greater can be conceived is the one case where the idea fixes a maximum, so the pattern works only there.
Pause and try this. Does the island objection settle the matter?
Ask whether the copy is a fair copy.
Here's the answer. It doesn't settle it. A parody works only if the parallel really is parallel, and that is exactly what the two sides dispute.
4. The cosmological argument
Line up a row of dominoes and find them all knocked flat. You'd ask what started it. A row of falling dominoes doesn't seem able to explain itself.
Thomas Aquinas's Summa Theologica opens its proofs with this sentence, in the translation of the Fathers of the English Dominican Province: "The existence of God can be proved in five ways." Those English words are the translators'. Of the 5 ways, the first 3 are versions of the cosmological argument, an a posteriori argument that starts from observed facts, such as that things change, are caused, or might not have existed. That leaves 2 ways, and the fifth is a design argument.
Here's the way from causes. Some things are caused to exist. Nothing causes itself, directly or through a loop. A chain of causes can't go back forever. So there's a first cause, a cause that nothing else causes. If those premises are true, the conclusion follows, so the argument is valid as reconstructed.
Pause and try this. Why does Dataset G call the cosmological argument a posteriori?
Look at its first premise.
Here's the answer. Its first premise, that some things are caused, is something you learn by looking at the world.
5. Pressing the cosmological argument
Picture that row of dominoes stretching back past every horizon, with no first domino at all. Each one is explained by the one before. Is anything left to explain?
That's the first objection: maybe a chain of causes can go back forever. The second asks about the conclusion. Even if there's a first cause, why should it be wholly good or all-knowing? It might be some basic physical event.
The argument's side replies to both. The chain it means is a chain of causes acting now, at once, like a hand that moves a stick that moves a stone. Take away the hand and nothing moves, however many sticks you add. And the argument only aims to show that a first cause exists; its defenders argue for the other qualities in further steps.
Pause and try this. A classmate says, "If everything has a cause, then what caused God?" Does that fit the argument?
Recall the exact premises.
Here's the answer. It doesn't fit. The argument says some things are caused and nothing causes itself; it concludes there's a first cause that nothing else causes.
6. The watch on the heath
Now the week's case on the course's thought-experiment roster. In Natural Theology, in 1802, William Paley asks you to imagine crossing a heath, rough open land, and finding a watch. You open it and see springs and wheels fitted together so the hands mark the hours. You'd conclude it had a maker.
Paley argues by analogy that, as a watch found on a heath shows a watchmaker, the order of living things shows a designer. That's the design argument, an a posteriori argument that starts from the order of the world and argues that this order shows a designer. The roster's question for the case is: does order show a designer?
The brass machine on the beach is a variation on Paley's case, written for this course.
Pause and try this. How is the design argument different from the cosmological argument?
Ask where each one starts.
Here's the answer. The cosmological argument starts from the bare fact that things are caused; the design argument starts from order, parts fitted together for a purpose.
7. Strength, and Hume's objections
Think of two houses with the same roof, the same windows, and the same odd blue door. You'd guess one builder made both. You wouldn't be certain, but the likeness gives your guess some support.
That's an argument from analogy, an inductive argument that reasons from the ways two things are alike to the conclusion that they are probably alike in a further way. So you judge Paley's argument for strength, not validity.
David Hume's Dialogues Concerning Natural Religion, published after his death in 1779, press it on two fronts. First, the analogy is weak: the universe is as much like a plant as like a machine. Second, order wouldn't show a single, perfect, or still-living designer. Those objections were in print 23 years before Paley's book. The design side replies that a partial analogy still gives support, and that the designer's other qualities need further argument.
Pause and try this. Is it right to call Paley's argument invalid?
Listen for one word in its conclusion: probably.
Here's the answer. No. It's inductive, so it's judged for strength. Calling it invalid misreads what kind of argument it is.
8. A tempting argument
Picture a student in a study group who has read Hume and gets excited. They say: if the universe was designed, it shows order; the universe was not designed; so it shows no order. That's Dataset B's argument 6, written for teaching.
Name the form. The second premise denies the antecedent, the "if" part, and the conclusion denies the consequent. That's denying the antecedent, and it's invalid. Think of a wild meadow full of flowers that no gardener planted. Order, like flowers, could come from some other source.
Pause and try this. Because argument 6 is invalid, must the universe have been designed?
Remember what an invalid argument fails to do.
Here's the answer. No. An invalid argument fails to support its conclusion; it doesn't show the opposite is true.
9. The problem of evil
Back to the shelter in the school gym. A nurse has worked all night. A child has a fever, and nobody there caused the flood. Someone asks: if God is wholly good and all-powerful, why did this happen?
That's the problem of evil, the argument that the evil and suffering in the world count against the existence of a God who is wholly good and all-powerful. In "Evil and Omnipotence," in 1955, J. L. Mackie argues that the existence of evil is logically inconsistent with the existence of a God who is wholly good and omnipotent. That's the logical problem of evil. A wholly good God would want to prevent evil, and an omnipotent God could. So if such a God existed, there would be no evil. But there is. The course's reconstruction of that is valid.
The evidential problem of evil says instead that the amount and kind of suffering make God's existence unlikely, rather than impossible. That makes it inductive.
Pause and try this. Does the problem of evil claim that religious people are bad?
Look at what the premises are about.
Here's the answer. No. It asks whether three claims fit together: that God is wholly good, that God is omnipotent, and that evil exists.
10. Free will and soul-making
Picture a parent teaching a teenager to drive. Keep the car in the driveway forever and there's no crash, but there's no driver either. Some goods seem to come only with some risk.
That's the thought behind the free will defense, which holds that a world with free creatures is better than one without them, and that even an all-powerful being cannot make creatures who are free yet certain always to choose well. A soul-making theodicy adds that hardship gives people the chance to grow in virtues such as courage and compassion.
The critic replies with a distinction. Moral evil is harm that comes from the free choices of people. Natural evil comes from natural events rather than anyone's choice, and the flood is natural evil. So the free will defense doesn't cover it by itself. And the evidential version presses on: is this much suffering needed for any good?
Pause and try this. Which kind of evil does the free will defense speak to most directly?
Think about where the defense finds its greater good.
Here's the answer. Moral evil, because it explains harm that comes from free choices; natural evil is where critics press it.
11. Faith, reason, and the wager
Think of someone deciding whether to carry an umbrella on a cloudy morning. They can't prove it'll rain, but getting soaked costs more, so they bring it.
In Week 8 you met Pascal's wager, from his Pensées, published after his death in 1670. It says the possible gain from believing in God is infinite and the possible loss finite, so a prudent person should wager that God exists. It's an argument about what to believe, not a proof that God exists.
That raises the question of faith and reason. On one view, belief in God should rest on argument and evidence. Paley's title names that project: natural theology, arguing for God's existence from reason and from observation of the world. On another view, faith can go beyond what argument shows, as many people trust a friend beyond the evidence alone. Both views have thoughtful defenders.
Pause and try this. Dataset G gives the wager the direction "for belief". Why not "for God's existence"?
Recall what the wager argues for.
Here's the answer. It argues that believing is the prudent bet. It gives no reason to think God exists.
12. The six arguments side by side
Line the arguments up. The ontological argument is a priori and for. The cosmological and design arguments are a posteriori and for. The wager is prudential and for belief. Hume's objections and the problem of evil are against. That's 3 for God's existence, 1 for belief, and 2 against, which makes 6.
Each has a reply. The island meets "an island has no maximum". The endless chain meets "causes acting now". Hume meets "a partial analogy still supports". The problem of evil meets free will and soul-making, and then natural evil presses back. The course keys no verdict on whether God exists. Your job is to state each argument so well that its own defenders would sign it.
Pause and try this. Dataset G has more arguments for than against. Does that mean the "for" side is winning?
Ask what the count is a count of.
Here's the answer. No. It counts how many classic arguments there are, not how good they are; one sound argument would settle it.
Closing
Let me pull it together. The philosophy of religion asks whether reason can settle the question of God. Anselm's ontological argument is a priori, and the island tests its pattern. Aquinas's first three ways argue a posteriori to a first cause. Paley's watch on the heath argues by analogy, and Hume calls the analogy weak. Argument 6 is invalid, by denying the antecedent. Mackie's logical problem of evil is valid as reconstructed, and the free will defense and soul-making answer it. Pascal's wager is about belief, not proof.
Next in this module come the Readings & Resources page, the lecture tutorial, the practice set, the quiz, the discussion, and the assignment. Next week, in Week 10, the ethics unit begins with relativism, God, and self-interest.
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