Understand the Cosmological Argument for God's existence, including Aquinas and modern formulations, and evaluate its logical strength.
The Design Argument used observation of nature to infer God. The First Cause Argument takes a different approach, asking about the origin of the universe itself:
The Cosmological Argument (also called the First Cause Argument) claims that the universe must have had a cause, and that cause must be God. Unlike the Design Argument, which looks at how things are organized, the Cosmological Argument asks why the universe exists at all.
The basic form is:
Thomas Aquinas presented this argument as his Third Way. He observed that things in the world are 'contingent' — they might or might not exist. A chair might not exist; you might not exist. But if everything is contingent, then at some point nothing would have existed (since contingent things can cease to exist). But we know something exists now, so there must be at least one 'necessary being' that exists by its own nature and cannot not exist. This necessary being, Aquinas concluded, is God.
Modern philosopher William Lane Craig developed the Kalam Cosmological Argument (named after medieval Islamic philosophy). It argues:
Craig argues that modern physics supports premise 2: the Big Bang shows the universe is not eternal. If it had a beginning, it must have had a cause.
Hume's Critique of Causation: Philosopher David Hume asked: how do we know that causation applies to the universe as a whole? We observe causation within the universe, but the universe itself might be different. Causation might only apply to things within space and time, not to space-time itself.
The Problem of God's Necessity: If everything must have a cause, why not God? Critics argue: if God can be an uncaused first cause, why can't the universe itself be uncaused? Why is God's necessity more plausible than the universe's necessity?
Infinite Regress: Some argue that causation doesn't require a first cause — an infinite chain of causes might be possible (A caused by B, B caused by C, C caused by D, etc., infinitely). We don't need a stopping point.
Quantum Mechanics: Some quantum events appear uncaused (radioactive decay, particle creation). If sub-atomic events can occur without causes, why can't the universe?
The Big Bang theory seems to support the argument that the universe had a beginning. But does science explain why the universe began? Physicist Stephen Hawking suggested that before the Big Bang, time did not exist, so asking 'what caused the Big Bang' is like asking 'what's north of the North Pole?' — the question is meaningless.
This raises a philosophical puzzle: if modern physics can explain the origin of the universe without God, does the argument fail? Or does explaining 'how' (the mechanism) differ from explaining 'why' (the purpose)? Some argue even a universe governed by physics requires explanation: why does anything exist at all?
Intuitive: It seems odd that something comes from nothing. Scientific support: The Big Bang suggests the universe had a beginning. Logical: Infinite regress is impossible in actual existence (we can have infinite abstract numbers but not infinite actual causes).
Special pleading: Why exempt God from the need for a cause? Physics: Modern science can explain the origin without God. Logic: Maybe causation doesn't apply to the universe as a whole, only things within it.
Below are statements about causation and the universe. Sort each into Support for the Cosmological Argument or Objection to the Argument.
Structure your answer:
Answer: The argument that since the universe began to exist, it must have a cause, and that cause is God.
Answer: Aquinas argued that contingent things (things that might not exist) need explanation. There must be at least one necessary being (something that must exist by its own nature), which is God.
Answer: William Lane Craig's version: (1) Whatever begins to exist has a cause, (2) The universe began to exist, (3) Therefore, the universe has a cause — God.
Answer: Contingent means dependent on something else for existence; something that might or might not exist. Chairs are contingent; they could be destroyed.
Answer: The objection that there might be an infinite chain of causes (A caused by B, B by C, C by D, etc.) without a first cause, so we don't need God.