Overview
This lecture covers Thomas Aquinas' Five Ways—arguments for the existence of God—explaining each and presenting key criticisms and counterarguments.
Aquinas’ Five Ways: Cosmological Arguments
- Aquinas' first four arguments are cosmological, relying on cause-and-effect and necessity.
- First Way: Argument from Motion—everything in motion is moved by something else; to avoid infinite regress, there must be an unmoved mover (God).
- Second Way: Argument from Efficient Cause—all things have a cause; to avoid infinite regress, there must be an uncaused first cause (God).
- Critics argue these arguments exempt God from their criteria without justification, and that the universe itself could be uncaused.
- Bertrand Russell suggests the universe may be a "brute fact" needing no cause.
- Some assert the Big Bang shows the universe had a beginning, implying a cause; others note the Big Bang may only explain the observable universe.
- David Hume argues cause-and-effect within the universe may not apply to the universe as a whole.
- Immanuel Kant claims we cannot meaningfully discuss causes beyond space and time.
The Third Way: Possibility and Necessity
- Distinguishes contingent beings (which might not exist) from necessary beings (which must exist).
- If everything were contingent, there would have been a time when nothing existed; since things exist now, there must be a necessary being (God).
- Critics question why the universe itself cannot be the necessary being or why infinite regress of contingent beings is ruled out.
The Fourth Way: Argument from Gradation
- Observes degrees of qualities (good, better, best) implying a standard of perfection.
- Argues a maximally perfect being (God) must exist as the source of all perfections.
- Critics dispute this due to varying definitions of "good" or "perfect" across cultures.
The Fifth Way: Teleological Argument (Argument from Design)
- Non-intelligent things act toward goals; this implies guidance by an intelligent being (God).
- Uses analogy of an archer guiding an arrow to its target.
- Critics argue natural processes and chance can explain complexity; rarity of life suggests randomness, not design.
Key Terms & Definitions
- Cosmological Argument — an argument for God’s existence based on the existence and causation of the universe.
- Teleological Argument — an argument for God’s existence from perceived evidence of design or purpose in nature.
- Infinite Regress — an endless chain of causes or explanations.
- Contingent Being — something that could possibly not exist.
- Necessary Being — something that must exist and cannot not exist.
- Unmoved Mover — a being that initiates motion without itself being moved.
Action Items / Next Steps
- Review Aquinas’ Five Ways and associated criticisms for deeper understanding.
- Optional: Read further on David Hume, Bertrand Russell, and Immanuel Kant’s critiques of cosmological arguments.