CF Dictionary · Critical Rationalism Terms
Three Worlds (Popper)
Popper's ontology: World 1 (physical), World 2 (mental), World 3 (abstract objects like ideas).
Popper's Three Worlds ontology distinguishes:
- World 1. Physical objects: rocks, brains, computers, books.
- World 2. Mental states: beliefs, feelings, experiences.
- World 3. Abstract objects: ideas, theories, mathematical truths, IGCs, error messages.
Why three worlds
- World 3 is real but abstract. Numbers exist; they don't exist in space-time.
- World 3 evolves. Ideas are subject to conjectures and refutations.
- World 3 affects Worlds 1 and 2. Theories guide action; books affect minds.
CR's argument from three worlds
CR argues that knowledge is largely in World 3 — it's criticisable, transmissible, and improves over time. Mental states (World 2) are private and unreliable; the public, abstract knowledge (World 3) is where progress happens.
CF's adoption
CF adopts the three-worlds view:
- IGCs are World 3. They're abstract objects with structure.
- Idea trees are World 3 representations of discussions.
- Paths Forward is about World 3 sharing and criticism.
Why it matters
- Knowledge is public, not private. That makes it criticisable.
- Knowledge evolves. It's not just whatever you happen to believe.
- Knowledge can be true or false independent of your belief about it.
"Three worlds theory (Popper's view of abstractions)" is one of CF's enumerated CR-specific concepts. — criticalfallibilism.com