What is this lesson about?
This lesson explains the ontological argument — a special kind of reasoning about whether God exists — in a simple way for an 11‑year‑old. It includes a short, friendly dialogue between two voices called the City of God (religious point of view) and the City of Man (human/secular point of view). It also shows how the lesson matches ACARA v9 ideas like thinking skills, asking questions and working in groups.
Step-by-step: The ontological argument in simple words
- Start with a definition: Think about the idea of the greatest possible being — someone so great that you cannot imagine anything bigger. Many people call this idea 'God'.
- Two kinds of existing: Something can exist in your mind (you can imagine it) or exist in real life (it is real).
- The key point: If the greatest possible being only existed in your mind, we could imagine a being greater — one that exists in real life too. But that would mean the being we first imagined wasn’t the greatest. So, the argument says, to truly be the greatest, that being must exist in reality.
- The conclusion: Because 'existing in reality' is better than 'only existing in the mind', the greatest possible being (God) must exist in reality.
A short, simple dialogue: City of God vs City of Man
Use this dialogue as a role play in class. Two people take turns speaking.
City of God: I can imagine the biggest, most perfect being — someone who has everything good and lacks nothing. If I can think of the very best being, then that being must be more than an idea in my head. The very best being must exist in real life, because a being that exists is better than one that only exists in my imagination.
City of Man: That’s interesting, but I’m not sure. Just because I can imagine something perfect doesn’t mean it exists. I can imagine a perfect island, but that doesn’t mean the island is real. Why should thinking about something make it real?
City of God: The argument says the idea of the greatest being is special. If it only existed as an idea, then we could imagine a greater one that exists in reality. That would be a contradiction, so the greatest being must exist in reality.
City of Man: Another idea is that existence is not a quality like being kind or powerful. Saying something exists doesn’t add a feature to it — it just says where the thing is. So, adding existence doesn’t make the idea of a being greater.
City of God: Some people reply that the argument is about logic: if you accept the starting idea (a greatest possible being), then the conclusion follows. Others say faith or experience are also important to believe in God.
Simple objections to discuss (and short answers)
- Gaunilo’s island example: You can imagine a perfect island, but that doesn’t make it real. Response: Supporters say the argument only works for a being that must exist by definition (some say only for God), not for islands.
- Kant’s reply: Existence is not a property like size or kindness. Saying something exists doesn’t make it better. Response: Defenders try other versions of the argument or say existence matters when we talk about the greatest possible being.
How this lesson maps to ACARA v9 (useful classroom links)
This lesson supports key skills and capabilities in ACARA v9. It is written for about Year 6 (11‑year‑old) and focuses on these areas:
- Critical and Creative Thinking: Identify different kinds of reasoning, examine an argument step by step, and think about objections.
- Ethical Understanding: Consider beliefs and values, and respect different viewpoints while discussing big questions.
- Intercultural Understanding: Learn how religious ideas shape communities (the City of God idea) and how different cultures think about existence.
- English (Speaking and Listening): Practice structured discussion, role play, listening to others and explaining ideas clearly.
- HASS - Inquiry skills: Pose questions (Does God exist?), locate simple information (what philosophers said), and use evidence to explain a conclusion.
Classroom activities (easy to run)
- Role play: Students act out the City of God and City of Man dialogue. Then swap roles and try giving the opposite view with respectful arguments.
- Think-Pair-Share: Each student writes one reason for and one reason against the ontological argument, then shares with a partner and the class.
- Draw it: Make two columns: reasons the argument might work, reasons it might not. Add one question you still want answered.
Short assessment questions (and sample answers)
- Q: What is the basic idea of the ontological argument? A: If you can imagine the greatest possible being, it must exist in real life because existing is better than just being an idea.
- Q: Name one objection to the ontological argument. A: You can imagine things that don’t exist (like a perfect island) — imagining something doesn’t make it real.
- Q: Why is it good to talk about both sides in a discussion? A: It helps us see different points of view, think more clearly, and make better decisions.
Teacher notes — differentiation
- For learners who need help: Use a short scripted dialogue to read aloud together and highlight key words (imagine, exist, better).
- For advanced learners: Introduce short quotations from Anselm or Kant in simple language and ask them to explain what the philosophers mean.
Glossary (simple words)
- Ontological argument: A logical argument that tries to show God exists just by thinking about the idea of God.
- Predicate: A property or feature of something (for example, being kind or being blue).
- Objection: A reason someone gives to show they don’t agree with an idea.
End with a question for students: Which part of the argument did you find most interesting or most confusing? Use that to start your class discussion.