Welcome to AS 8: Arguments for the Existence of God
Hello and welcome! If you are studying for your CCEA AS Level Religious Studies (Unit AS 8: An Introduction to the Philosophy of Religion), you have come to the right place. Philosophy of religion explores the biggest questions ever asked: Does God exist? How can we know? Can human reason prove the divine?
Don't worry if philosophy feels daunting at first with all its technical words. We will break down every single concept step-by-step, using clear real-world examples, memory aids, and examiner tips so you can achieve the highest marks in both AO1 (Knowledge and Understanding) and AO2 (Evaluation and Analysis).
Exam Snapshot:
Unit AS 8 is assessed through a 1 hour and 20 minute exam worth 50% of your AS award (20% of the full A Level). You will answer one question in Section A and one in Section B. To get top marks, you need both clear factual recall and sharp critical evaluation.
Philosophical Toolkit: Two Key Distinctions
Before diving into the arguments, you must master two essential distinctions. Getting these mixed up is a classic examiner complaint!
1. How We Gain Knowledge: A Posteriori vs A Priori
• A Posteriori (Empirical): Arguments based on sense experience and observation of the world around us. You look at the universe first, gather evidence, and draw a conclusion.
Memory Aid: Posteriori = Post-experience (after looking at the world).
• A Priori (Rational): Arguments based on pure reason and logic alone, without needing empirical observation or physical evidence.
Memory Aid: Priori = Prior to experience (before looking at the world).
2. How Arguments Are Structured: Inductive vs Deductive
• Inductive Arguments: The premises provide strong evidence, but the conclusion is probable rather than 100% certain. (Most a posteriori arguments are inductive).
• Deductive Arguments: If the starting premises are true, the conclusion must necessarily be true. There is no room for doubt if the logic holds. (The Ontological argument is deductive).
Chapter 1: The Cosmological Argument
The word Cosmological comes from the Greek word cosmos, meaning "world" or "universe". It is an a posteriori, inductive argument that looks at the existence of the universe and asks: Why is there something rather than nothing?
St Thomas Aquinas (1225–1274): The Three Ways
In his famous work Summa Theologiae, St Thomas Aquinas offered five ways to prove God's existence. The first three make up the Cosmological Argument:
1. The First Way: Argument from Motion (Kinetic)
Aquinas observed that things in the world are in motion (changing from potentiality to actuality). Whatever moves must be moved by something else, because nothing can move itself. This chain of movement cannot go back to infinity (no infinite regress), because without a first mover, there would be no subsequent movement at all. Therefore, there must be an initial Unmoved Mover that sets everything in motion without being moved by anything else—and this everyone understands to be God.
2. The Second Way: Argument from Causation (Efficient Cause)
Aquinas observed that every effect has an efficient cause. Nothing can be the cause of itself, because it would have to exist before itself, which is impossible. You cannot have an endless chain of causes going back to infinity (no infinite regress of causes). Therefore, there must be a First Cause that is uncaused, which initiated all other causes—and this is God.
3. The Third Way: Argument from Contingency
Aquinas noted that objects in the universe are contingent—they begin, change, and eventually cease to exist (they depend on something else for their existence). If everything in the universe were contingent, then given infinite time, there would have been a time when absolutely nothing existed. If that were true, nothing could ever have started to exist! Therefore, not everything can be contingent. There must exist a Necessary Being—a being that cannot not exist, having no beginning or end, which brought everything contingent into being. This Necessary Being is God.
The Kalam Cosmological Argument: William Lane Craig
A modern revival of an ancient Islamic argument, championed by Christian philosopher William Lane Craig:
• Premise 1: Whatever begins to exist has a cause.
• Premise 2: The universe began to exist (supported by modern astrophysics and the Big Bang).
• Premise 3: An actual infinite cannot exist in the real physical world (you cannot cross an infinite series of past events to reach the present day).
• Conclusion: Therefore, the universe has a personal First Cause that chose to create it out of nothing (creatio ex nihilo)—which is God.
Challenges to the Cosmological Argument
1. David Hume’s Critique of Causation:
The Scottish Enlightenment philosopher David Hume argued that we cannot logically prove that every event has a cause. We simply observe Event A followed by Event B repeatedly and assume a necessary link (a "habit of mind" or psychological expectation). Because we cannot experience the creation of a universe, we cannot claim with certainty that the universe must have a cause.
2. Bertrand Russell and the Fallacy of Composition:
Philosopher Bertrand Russell famously argued that just because every individual human being has a mother, that does not mean the entire human race has a collective mother! In the same way, just because every individual object within the universe has a cause, it is a logical error (the fallacy of composition) to claim that the universe as a whole must have a cause. Russell famously declared: "The universe is just there, and that's all." (It is a brute fact).
Key Takeaway for Cosmological Argument:
Aquinas uses experience to argue that motion, causation, and contingency demand a transcendent Unmoved Mover, First Cause, and Necessary Being. Critics like Hume and Russell challenge whether the universe as a whole requires a cause at all.
Chapter 2: The Teleological (Design) Argument
The term Teleological comes from the Greek word telos, meaning "end", "goal", or "purpose". It is an a posteriori, inductive argument based on the evidence of order, complexity, regularity, and purpose in the natural world.
Key Proponents of the Design Argument
1. St Thomas Aquinas: The Fifth Way (Governance/Guidedness)
Aquinas observed that non-intelligent objects in nature (like plants, planets, or weather cycles) act regularly to achieve the best result. However, things that lack intelligence cannot move towards a specific goal unless directed by an intelligent being. Aquinas used the analogy of an arrow and an archer: an arrow cannot reach its target on its own; it must be aimed and guided by an intelligent archer. Therefore, an intelligent designer must exist who directs non-intelligent natural objects to their purpose—this is God.
2. William Paley (1743–1805): The Watchmaker Analogy
In his book Natural Theology, William Paley asked the reader to imagine walking across a heath and striking their foot against a stone. You might assume the stone had lain there forever. But if you found a pocket watch on the ground, its intricate complexity, delicate cogs, and clear purpose (telling time) would immediately lead you to conclude that it had a designer—a watchmaker.
Paley argued that the natural world displays far greater complexity, order, and purpose than any watch (e.g. the human eye, designed for sight; the wings of a bird, designed for flight). Therefore, the universe must have had a grand Designer—God.
3. F.R. Tennant: Modern Design Arguments
• The Anthropic Principle: Tennant argued that the universe is extraordinarily fine-tuned to produce and sustain human life. If physical constants (like gravity or the expansion rate of the universe) were altered even minutely, life could never have emerged. This precision points to deliberate divine design.
• The Aesthetic Argument: Humans have a deep appreciation for beauty, art, literature, and music. This capacity for aesthetic appreciation provides no survival advantage in terms of evolutionary biology. Tennant argued that God provided beauty and the ability to enjoy it as a loving gift to humanity.
Challenges to the Teleological Argument
1. Charles Darwin (Evolution by Natural Selection):
Darwin’s theory of evolution provided a purely natural explanation for the appearance of design. Random genetic mutations and natural selection over millions of years allow organisms to adapt to their environments. What Paley saw as "planned design" is actually the result of blind biological survival.
2. David Hume’s Critiques:
Examiner Warning: Hume made specific criticisms against the Design argument that are different from his points on the Cosmological argument!
• The Machine vs. Organism Analogy: Paley compared the world to a machine (a watch). Hume pointed out that the universe is far more like a growing, natural vegetable or living organism than an engineered mechanical clock.
• Flawed Design / The Problem of Evil: If the world has a designer, the existence of natural disasters, disease, and suffering suggests the designer is either incompetent, malevolent, or an "infant deity" who abandoned a flawed project.
Key Takeaway for Teleological Argument:
Design arguments move from observed complexity and purpose (Aquinas's archer, Paley's watch, Tennant's fine-tuning) to a divine Architect. Darwin and Hume counter that nature can be explained by evolutionary mechanisms, flawed comparisons, and unguided natural processes.
Chapter 3: The Ontological Argument
The word Ontological comes from the Greek ontos, meaning "being" or "essence". Unlike the previous two, this is an a priori, deductive argument. It does not look at the physical world at all; instead, it seeks to prove God's existence through the definition and logic of the concept of God.
1. St Anselm of Canterbury (1033–1109): Proslogion
Anselm aimed to demonstrate that even "the fool who says in his heart there is no God" (Psalm 14) is contradicting himself logically.
• Step 1: Anselm defined God as: "That than which nothing greater can be conceived" (the ultimate greatest possible being).
• Step 2: Even the atheist understands this definition in their mind (in intellectu).
• Step 3: It is greater to exist both in the mind AND in physical reality (in re) than to exist in the mind alone.
• Step 4: If God existed only in the mind, we could imagine an even greater being: one that also exists in reality.
• Conclusion: Therefore, to remain "that than which nothing greater can be conceived", God must exist in reality.
2. René Descartes (1596–1650): Meditations
Descartes defined God as a "supremely perfect being" who possesses all perfections.
• Existence is a perfection; non-existence is a flaw or limitation.
• Therefore, a supremely perfect being must possess existence.
• Analogy of the Triangle: Just as you cannot conceive of a triangle without three internal angles adding up to 180 degrees, and you cannot conceive of a mountain without a valley, you cannot conceive of a supremely perfect being without the attribute of existence. Existence is inseparable from the very essence of God.
Challenges to the Ontological Argument
1. Gaunilo of Marmoutiers: The "Perfect Island"
Gaunilo, a contemporary monk of Anselm, argued that Anselm's logic was flawed using a method called reductio ad absurdum (showing a concept leads to an absurd conclusion):
Imagine the most perfect, lost island conceivable, overflowing with riches. Using Anselm's logic, because an island existing in reality is greater than one existing only in the mind, this perfect island must exist in reality! Gaunilo argued that you cannot define an object into actual physical existence simply by imagining it as perfect.
2. Immanuel Kant: "Existence is NOT a Predicate"
Crucial Concept to Master: A predicate is a descriptive quality, characteristic, or attribute added to a subject (e.g. "The dog is brown, fluffy, and friendly").
Kant argued that saying "x exists" adds no new descriptive information to our concept of x. Saying "I have 100 thalers (coins)" describes their quantity and nature; saying "and they exist" does not add a single extra coin to my pocket. Because existence is not a genuine predicate, Descartes and Anselm cannot treat existence as a necessary property that God must possess.
Key Takeaway for Ontological Argument:
Anselm and Descartes argue from pure reason: by definition, a supremely perfect or unsurpassable being must include existence. Critics like Gaunilo and Kant argue that you cannot define things into existence, and that existence does not function as a descriptive predicate.
Chapter 4: The Argument from Religious Experience
Religious experience is an a posteriori argument that claims personal, direct encounters with the divine provide strong grounds for believing in God's existence.
Key Forms of Religious Experience
• Visions and Voices: Experiencing direct visual or auditory messages from God, angels, or holy figures (e.g. St Paul on the road to Damascus).
• The "Numinous" (Rudolf Otto): Otto described the core of religious experience as the numinous—an encounter with the "mysterium tremendum et fascinans" (an overwhelming, awe-inspiring mystery that both terrifies and magnetically attracts the human soul).
Richard Swinburne: Defending Religious Experience
Modern philosopher Richard Swinburne argued that we should trust religious experiences unless we have clear, compelling evidence to doubt them. He formulated two crucial principles:
1. The Principle of Credulity:
We ought to believe that things are as they seem to be, unless we have special reasons to doubt them (e.g. if the person was hallucinating, under the influence of drugs, or has a proven track record of lying). If someone genuinely feels they experienced God, we should accept it as probable.
2. The Principle of Testimony:
In everyday life, we normally believe what other people tell us unless we have good reason not to. Therefore, we should trust the testimony of people who report religious experiences unless we have clear evidence of dishonesty or mental impairment.
Evaluation of Religious Experience (AO2)
• Strengths: Experiences can be life-transforming for the individual; widespread across all cultures and historical eras; cumulative weight of millions of testimonies.
• Weaknesses: Subjective and impossible to verify empirically; conflicting truth claims (different religions experience different deities); psychological and physiological alternative explanations (e.g. temporal lobe epilepsy, wish-fulfilment, cognitive bias).
Key Takeaway for Religious Experience:
Personal direct encounters (numinous, visions, voices) offer strong subjective proof to the experiencer. Swinburne argues our normal rules of trust (credulity and testimony) should extend to these accounts, though critics point out they lack objective empirical proof.
Quick Summary & Comparison Matrix
Keep this mental map clear for your exam:
1. Cosmological: A posteriori / Inductive / Key thinkers: Aquinas (1st, 2nd, 3rd Ways), Craig (Kalam) / Main Critics: Hume, Russell.
2. Teleological: A posteriori / Inductive / Key thinkers: Aquinas (5th Way), Paley, Tennant / Main Critics: Darwin, Hume.
3. Ontological: A priori / Deductive / Key thinkers: Anselm, Descartes / Main Critics: Gaunilo, Kant.
4. Religious Experience: A posteriori / Inductive / Key thinkers: Otto (Numinous), Swinburne (Credulity & Testimony) / Main Critics: Psychological/scientific critiques.
Top CCEA Exam Tips & Common Pitfalls to Avoid
1. Do Not Mix Up Argument Types: Never label the Ontological argument as a posteriori or the Cosmological argument as a priori.
2. Differentiate Hume’s Criticisms: When evaluating Design, write about Hume’s machine vs. vegetable/organism critique and flawed design. When evaluating the Cosmological argument, write about Hume's critique of the causal link!
3. Explain Kant's Predicate Point Clearly: Do not just write "Kant said existence is not a predicate." Explain why: a predicate adds a descriptive characteristic, but saying something exists merely affirms that an object matching that description is real.
4. Balance AO1 and AO2: Mark schemes award substantial marks for critical evaluation. Always evaluate how persuasive an argument is, identify its weaknesses, and reach a balanced, justified conclusion.