The Probability Calculation Method

A protocol for working out your own answer instead of waiting for someone else's: list the risks, price them yourself, do the arithmetic, state your uncertainty, and then act like someone who believes their own numbers.

The conversation about urgency stalls in the same place every time: maybe you are right, maybe not, I cannot tell, so I will wait until it is clearer. The waiting becomes permanent. This hands over an instrument instead of an argument — do not believe anyone; do the arithmetic yourself.

The steps. List the factors active in your own time and place, adding and removing freely; the list is yours. Price each one: what is the realistic chance, in your judgment, that this resolves well over the horizon you care about (Hypothesize, Measurement). Weight by severity, because a food-system failure is not a fashion cycle, and justify the weighting. Do the joint arithmetic — which is where the exercise bites, since independent events with individually comfortable odds combine into something very uncomfortable. Adjust for interdependence, because real risks fail together rather than separately (Multi-Polar Traps, Systemic Failure Modes). Do it per horizon — three years reads differently from thirty (The Time Horizons). State your confidence bands, which is the discipline separating serious risk-reading from both doomism and denial (We Do Not Know, Honesty about time). Weight the scenarios with your own numbers rather than anyone else's (The Five Collapse Scenarios). Decide — and the whole point is here: match behaviour to your own figures, whichever way they came out. Update as reality produces evidence, quarterly or yearly, as a living document (Improvement log, Navigating Towards Truth).

What it does is move the authority. It asks nobody to believe a diagnosis, removes the I don't know what to think exit, surfaces the assumptions a person did not know they were carrying, and is teachable onward — the conversation stops being trust me and becomes run it yourself (Asking Questions, Types Of Knowing).

It pairs with The Asymmetry of Consequences: once someone has their own number, the asymmetry tells them what to do with it, and low numbers still point the same way.

Every figure in the source is an estimate, not a measurement — and a particular kind: the source book is a 2023 dialogue with a language model whose own training ended earlier, and it says of its own probabilities that they are highly speculative. The arithmetic illustration it is famous for — many risks, each generously given even odds, multiplied — is an illustration under an independence assumption the page itself calls false. The method is the durable part; the numbers are somebody's guess from a particular year, and should be replaced by the reader's own.

Also called: do the math yourself · the ten steps Stands on: Decision Making · The Meta Crisis · We Do Not Know Opens onto: The Asymmetry of Consequences · The Five Collapse Scenarios · The Window · The Time Horizons · The future triad — Best · Worst · Actual · Navigating Towards Truth · Measurement · The Five Verification Filters and the Spectrum of Knowing In play: the table — run once by a household or a Cell, and revisited each year Sources: LIØNSBERG Wiki Books/LIØNSBERG, Earth, and the Cosmos/Cards/The Probability Calculation Method.md (Card, captured) — drawn from The Last Chance, which is a 2023 transcript of a dialogue with a language model Open: The Card reproduces the source's worked numbers without the source's own provenance or its stated speculativeness; a reviewer flagged this and it is unrepaired. · Assigning a probability to a civilisational outcome is not the same kind of act as assigning one to a coin, and the method does not say so. · The protocol is only as good as the factor list, and a list assembled by someone already persuaded will return what they expected.