1 · The shared trunk — mid-2025 to October 2027
Drag the scrubber. The story uses a fictional leading US lab (OpenBrain) and a fictional consolidated Chinese effort (DeepCent) to avoid naming real companies.
2 · What flips the ending?
Six assumption toggles. The oversight vote is the master fork; the others shift how likely the pause is to hold.
A note on dating
AI 2027 is a 2025 scenario to explore, not the authors' current forecast. The authors later revised their views — a mid-2025 note pushed the median timeline back roughly a year and a half, and by late 2025 / early 2026 the lead author's median AGI estimate had moved to the early 2030s. A 2026 follow-up sketches a more optimistic path. Read this as a what-if with a fork, not a prediction.
Also from the authors: the slowdown ending is explicitly NOT their policy recommendation. It depicts what they thought would more likely preserve human control — not a roadmap they endorse.