The Oldest Argument

Logic Truth and the Limits of Reason · Open board

The shapes an argument can take, and where each one can leak. This lesson points those shapes at the oldest question people have argued about: is there a God? It takes no side. It hands you the five arguments that have carried the debate for a thousand years and shows you exactly which premise each side has to deny.

Before you start. Logic, Truth & the Limits of Reason split a good argument into two checks. An argument’s shape is valid when the conclusion has to follow if the premises are true; it is sound when it is valid and the premises really are true. Every argument below has a shape most philosophers accept as valid, so the whole fight is over the premises, and that is where you will look.

The idea in 30 seconds

The first-cause argument says the chain of causes cannot run back forever, so something uncaused must start it; its weak point is whether that is true, and whether a first cause must be a God.
The design argument says things that fit a purpose point to a designer; natural selection and the point that we could only find ourselves in a life-allowing universe are its two main rivals.
The argument from definition says the greatest conceivable being must exist; its weak point is whether “exists” is a quality that can make something greater.
The problem of evil asks why a being able, knowing and willing to stop suffering allows it; a defence from free choice answers the logical version better than it answers natural disasters.
Pascal treats belief as a bet with an infinite prize, and the existence of many rival religions, each offering its own infinite prize, is the standard reply.

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