Against Certainty

Think clearly when you don't know.

Against Certainty is a small field guide for thinking under uncertainty — with interactive mini-tools instead of theory. The Base-Rate Machine uses 100 people to show why a positive test is usually a false alarm. The Panic-to-Probability Converter turns a concrete fear into a sober reading of how strong your evidence really is. "Your Risk in Micromorts" puts risks in proportion — and shows the dangerous thing is usually the boring one you do constantly. Plus essays, scenarios and fallacy cards. English, free, no login. The tools run entirely in your browser; your inputs are never transmitted.