Study Notes on Aquinas and the Existence of God

Teleological Argument
  • Definition: The teleological argument, derived from the Greek word telos meaning 'end' or 'goal', proposes that purposive behavior observed in non-conscious objects suggests the existence of an intelligent being, which is understood to be God.
  • Observation: Even non-conscious objects exhibit behavior that is directed towards ends or goals, which necessitates some guidance by an intelligent being.
  • Relation to the Argument from Design: This argument is closely related to the 'argument from design', popularized in the 18th century, which was heavily critiqued by philosopher David Hume.
  • Examples Not Provided by Aquinas: Aquinas does not provide explicit examples of teleological actions here but references other works (e.g., Summa Contra Gentiles) where he discusses how plant leaves are shaped to protect the fruit and how the structure of animals is suited for biting and chewing.
  • Counterpoint from Modern Science: Modern evolutionary science seeks to explain goal-oriented phenomena through purely mechanical processes.
  • Defense by Supporters of Aquinas: Advocates for Aquinas argue that the ultimate explanation for such phenomena should be found in the guiding intelligence of God.
Five Ways to Prove the Existence of God

  1. First Way: Argument from Motion

    • Premise: Observations confirm that some things are in motion.
    • Explanation of Motion: Whatever is in motion is moved by something else, indicating that nothing can be moved without an external cause.
    • Concept of Potentiality and Actuality:
      • Potentiality: A state where something has the potential to be in motion (e.g., wood being heated).
      • Actuality: The state of being in motion (e.g., fire heating the wood).
    • Contradiction: It is impossible for something to be both in actuality and in potentiality at the same time in the same respect.
    • Conclusion: As the sequence of movers cannot continue infinitely, there must be a first mover that is unmoved, which is understood to be God.

  2. Second Way: Argument from Efficient Cause

    • Premise: The world contains an ordered series of efficient causes.
    • Definition of Efficient Cause: An efficient cause is something that brings about an effect (e.g., a cause produces an effect).
    • Impossibility of Self-Causation: It is impossible for something to cause itself, as it would have to exist prior to itself.
    • Argument Against Infinite Regress: A series of efficient causes cannot extend infinitely into the past.
    • Conclusion: There must be a first efficient cause, which we call God.

  3. Third Way: Argument from Possibility and Necessity

    • Premise: Some entities exist that are merely possible, meaning they can either exist or not exist.
    • Example: Things that come into being and pass away.
    • Conclusion on Necessity: If everything were possible, there would be a time when nothing existed; thus, not everything can be contingent (possible).
    • Essential Being: Therefore, there must be something that exists necessarily, and this cannot originate from another source.
    • Identity of Necessary Being: This being, which is the source of necessity itself, is referred to as God.

  4. Fourth Way: Argument from Gradation

    • Premise: There are gradations or hierarchies of goodness, truth, nobility, etc. among things.
    • Definition of Gradation: Terms like 'more' and 'less' apply to things relative to the greatest of those kinds.
    • Reference to Aristotle: As stated in Metaphysics, the greatest is the cause of all that is of that kind (e.g., fire is the primary cause of all hot things).
    • Conclusion: For all goodness and perfection, there must be a greatest source, which is called God.

  5. Fifth Way: Argument from Design

    • Premise: Non-conscious beings demonstrate directed behavior toward goals.
    • Examples: Natural entities operate consistently to achieve their ends, like arrows directed by an archer.
    • Indication of Guidance: Such directed behavior implies guidance by an intelligent being, as direction cannot occur without intelligence.
    • Conclusion: Therefore, there exists an intelligent being that directs all natural things towards their ends, termed God.
Additional Note on Evolution
  • Reference by Aquinas: Aquinas seems to contemplate the possibility of evolution, as referenced in Summa Theologiae, I, q. 118, art. 2. This acknowledgment indicates an openness to reconciling his arguments with emerging scientific understandings of life.