A historical counterfactual needs limits on how much it changes. It can retain the real people and circumstances while testing the consequences of a different decision. The purpose is to look for missing explanations in the history. As each proposed outcome becomes the foundation for another assumption, the exercise moves further into fiction. Keeping close to the available evidence also reveals decisions for which few plausible alternatives existed.
Notable Point · 42:26-43:23
Counterfactuals before they become fiction
A disciplined alternate history changes as little as possible and stops when accumulated assumptions outrun the historical evidence.