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KAKURITSU

the mathematics of chance

The Bernoulli Trial

Every moment presents a binary fork: success or failure, heads or tails, yes or no. Jakob Bernoulli understood that from this simplest of experiments — the single trial with two outcomes — the entire architecture of probability could be constructed.

The probability of exactly k successes in n independent trials, each with success probability p:

P(X = k) = C(n,k) · pᵏ · (1-p)ⁿ⁻ᵏ

Conditional Probability

Bayes' theorem reveals how prior beliefs transform under new evidence. The probability of hypothesis H given evidence E is not merely the overlap of the two events, but a recalibration of certainty itself.

P(H|E) = P(E|H) · P(H) / P(E)

In the language of conditional probability, nothing exists in isolation. Every outcome is entangled with every other, a web of dependencies that only careful mathematical reasoning can untangle.

Gaussian
Binomial
Poisson
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-2σ -1σ μ +1σ +2σ

The Normal Distribution

At the heart of probability lies the bell curve — the Gaussian distribution — nature's most elegant statement about uncertainty. Given enough independent random variables, their sum converges to this shape. This is the Central Limit Theorem: chaos, aggregated, produces order.

f(x) = (1/σ√2π) · e^(-(x-μ)²/2σ²)
Gaussian

The Dice

Six faces, six fates. The earliest randomizing device, found in ancient Mesopotamia. Each throw is a conversation with pure chance.

P(n) = 1/6
♠♥

The Cards

52 possibilities held in the hand. Card games are probability laboratories disguised as entertainment.

P(ace) = 4/52

Pachinko

Chrome spheres cascading through pins — a Galton board made physical. In Tokyo's parlors, probability becomes spectacle.

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The Lottery

Against astronomical odds, millions hope. The lottery is probability's greatest paradox: mathematically foolish, emotionally irresistible.

P ≈ 1/292,201,338

Fortune

Omikuji, tarot, I Ching — humanity's oldest attempt to negotiate with randomness. Divination is probability wearing a spiritual mask.

運命 | 확률

As n → ∞, uncertainty collapses into truth.

The law of large numbers promises: given enough trials, the observed converges to the expected. Probability is not the absence of certainty — it is the path toward it.

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