• The chapter addresses the philosophical question of greatest importance: the existence of God.

• ‘God’ is understood here as a supreme mind, either omnipotent or at least more powerful than anything else, and supremely good and wise.

• A purely philosophical work does not cover claims of revelation, which often underpin belief in God and His attributes.

• Philosophers have developed a great number of arguments supporting the existence of God.

THE ONTOLOGICAL ARGUMENT

• The ontological argument attempts to prove God’s existence solely from the idea or definition of God.

• God is defined as the most perfect being or one possessing all positive attributes.

• The argument claims existence is a ‘perfection’ or positive attribute, so God must exist to avoid contradiction.

• A major objection is that existence is not an attribute or perfection.

• Saying something exists differs fundamentally from ascribing an ordinary attribute; existence affirms the concept is realized in fact, not that the concept gains a new characteristic.

• Linguistic confusion arises because sentences like “cats exist” and “cats are carnivorous” share grammatical form but differ logically.

• Saying “cats are carnivorous” adds a quality to already existing beings; saying “cats exist” asserts that propositions describing cats are true sometimes.

• Negative case clarity: “dragons are non-existent” denies any entity has dragon-properties, without presupposing dragons exist, unlike “lions are not herbivorous” which presupposes lions exist.

• Some say the ontological argument imperfectly expresses a principle: what we must think logically must be true of reality.

• This principle is a necessary presupposition for all knowledge and justified belief.

• Without this principle, no fact could be accepted and even experience would be unreliable.

• However, this principle differs significantly from the traditional ontological argument and should not be conflated.

• Moreover, to use this principle to prove God’s existence, one must already accept or justify that God exists, making the argument circular or self-evident.

THE FIRST CAUSE ARGUMENT

• The cosmological (first cause) argument is more important than the ontological argument.

• St. Thomas Aquinas rejected the ontological argument but made the cosmological argument the intellectual basis of his theism; Roman Catholic orthodoxy often regards it as proving God’s existence with mathematical certainty.

• The argument has been influential in Protestant thought and accepted in various forms by eminent philosophers like Aristotle, Descartes, Locke, Leibniz.

• The argument states we require a reason to account for the world, and this ultimate reason must be self-sufficient, requiring no further cause.

• God is conceived as the only being self-sufficient and his own reason, not requiring a cause beyond himself.

• The argument appeals to the human tendency to demand reasons for things and opposes the problematic idea of infinite regress.

• It is plausible to conceive God as a being that necessarily exists and does not need an external cause.

• The argument assumes the principle of causation, where causes provide reasons for effects; this assumption is more accepted in Roman Catholic philosophy than among most modern philosophers.

• Doubts arise about whether the causal principle applies to the world as a whole; if applied analogously, the argument weakens.

• A major difficulty is understanding how anything could be its own reason, implying it must exist necessarily a priori.

• It is easier to see a priori necessity in logical relations but much harder to see how existence itself could be logically necessary; non-existence presents no contradiction.

• While not impossible logically, the notion of God’s necessity remains incomprehensible to many.

• The cosmological argument is invalid as a complete proof but might retain some probability value:

  • The world is more likely rational if theism is true than if it is not.

  • It is more reasonable to suppose the universe is rational rather than irrational.

• Many modern thinkers reject this, but science presupposes rational coherence beyond experience, logic, and math.

• Science prefers hypotheses that make the universe more coherent and rational, even if incomplete.

• Theism does not yet fully rationalize the universe (e.g., how God is uncaused, problem of evil), but it comes closer than other views.

• Opposing views often treat the world as a brute fact without explanation.

• Viewing the world as purpose-driven and valuable is closer to rational explanation than denying purpose or value.

• By the scientific principle of preferring the hypothesis bringing the universe nearest to a coherent rational system, theism is more acceptable.

• The cosmological argument’s strong point: it remains incredible that the physical universe just happened by chance, even if composed of trillions of electrons.

• The universe calls out for some further explanation beyond mere physical occurrence.