확률
a workshop for probability — chance pinned to paper, ink staining the margins, possibility weighed by hand.
The simplest probability problem is also the deepest. Flip a fair coin: P(H) = ½, P(T) = ½. Add them, you arrive at 1. Everything has happened.
But "fair" is a promise — the metal does not know it. Each flip is an experiment renegotiated with gravity, geometry, and the surface it lands on.
Roll two dice, sum the faces. The probabilities are not flat — they pile up in the middle, the way stones gather in a riverbed. This is what mathematicians mean by a distribution.
A beautiful contradiction lives in the word: certainty about uncertainty. We do not know which face the coin will show, but we know — with mathematical exactness — the rate at which heads will arrive across enough trials. Probability is the discipline of being precise about not knowing.
// posterior = (likelihood × prior) ÷ evidence
// a rule for updating belief in the presence of new ink.
- [ x ] begin with a prior — your honest first guess.
- [ x ] observe — write down what actually happened.
- [ x ] update — the new posterior becomes tomorrow's prior.
- [ ] repeat, forever, calmly.