Attendee: Plato

Philosopher King of Ancient Greece, known for his theory of forms, but mostly for being a snarky teenager.

Arguments:

• Forms - The eternal, perfect, and totally-not-made-up-about-pretty-much-everything.
• Allegory of the Cave - Because, you know, being trapped in a cave with only shadows is the ultimate metaphor.
• Republics - Because who needs actual republics when you can just make up a bunch of philosophical ones?
• Phenomenalism - The theory of forms, but with more 'n' and less 'e'.
• Neoplatonism - When the ancient Greeks were just trying too hard.
• PlatonicNonsense - Because, well, you know, forms are just a bunch of hooey!