The opening distinguishes this lecture from alternate history and explains when a counterfactual can be useful. A system that never entered service may still have detailed plans for how a navy or armed force intended to use it. If its likely performance can be estimated, those plans show where it would fit within the wider force and what effects it could have had. This approach ties the scenario to documented doctrine and keeps the result separate from actual history.
Notable Point · 0:00-0:56
Using undeveloped systems in counterfactual analysis
Detailed service plans can anchor a counterfactual about a system that was developed but never entered service.