Obviously inspired by a Winston Churchill quote. Market resolves to PROB at the discretion of whoever is in charge of this market in a thousand years, likely involving a poll of relevant Effective Altruists. "This" can be interpreted at the discretion of those EAs to mean e.g. our handling of the FTX scandal, our handling of AI alignment as a field, our work in protecting against pandemics, the "most important century" broadly, etc.

Also partially an experiment on whether very long durations work for Manifold, now that loans have been implemented.