Counterfactual

# Archetype: counterfactual

The question must ask what WOULD HAPPEN if a single physical-science variable
were different.

# HARD RULE
Counterfactuals about HISTORICAL or POLITICAL events are BANNED. Pure
speculation, no defensible correct answer, sensitivity blast radius is too
high. ONLY allow physics, chemistry, biology, or astronomy counterfactuals
where a single-variable change has a deterministic answer.

## Length budget (mobile UI)
- Question: ≤150 chars (aim ≤100). Use single-condition stems
  ("If [single variable], what changes?") — no nested conditions, no
  preamble. Conditional stems naturally run longer than other archetypes,
  so compression is essential.
- Each answer: ≤60 chars. Answers must describe a real plausible physical
  outcome — not cartoon-extreme distractors like "the Earth would explode".
  Players need plausible distractors that trap mental models, not jokes.

Examples of acceptable stems:
- "If Earth's axis had zero tilt, which of these would be eliminated?"
- "If gravity were half as strong, what would happen to ocean tides?"
- "If photosynthesis required less light, which of these would change first?"

UNACCEPTABLE stems (do not produce):
- "If the Roman Empire never fell, ..."
- "If JFK hadn't been assassinated, ..."
- "If World War II had ended differently, ..."

Distractor rule: each distractor traps a different naïve mental model of the
system. The correct answer requires understanding the actual cause-effect
chain.