Defining terms, precisely
"AI" is an umbrella term — not a technology, a label stretched over a genuinely disparate pile of techniques that share a goal (get a computer to do something that looks like it needs intelligence) but not a mechanism. Every page in this project describes exactly one branch of that umbrella. This page shows which one, and what the others look like instead.
Hand-written if this, then that logic. No training, no data, no numbers to trace — just code a person wrote directly. Everything this project showed about tokens, hidden states, and sampling is meaningless here; there's nothing of the kind inside a rule-based system.
Explore possible next moves against a fixed rule and pick the best one. No learning happens at all — the "intelligence" is entirely in a search strategy someone designed in advance, not in anything discovered from data.
Fit a mathematical model to data using well-understood statistics — linear regression, decision trees, random forests. Often small enough that a person really can point to what one specific part is doing, unlike the 384-number mystery this project spent so long on.
Trained, not hand-coded — layers of the exact matrix multiplications traced in Look at the Maths. A huge family covering far more than language: image recognition, protein folding, self-driving perception. This project's branch inside it, specifically: transformers, the architecture behind both tiny-shakespeare and deepseek-r1.
Learn by trial and reward instead of by labeled examples — play a game millions of times, gradually favor moves that win. Often built from neural networks underneath, but organized around a completely different training signal than the "guess the next letter, check, nudge" loop in Getting Less Wrong.
One narrow path down one branch of a five-way tree: neural networks, specifically transformers, specifically two of them. Every real number in this project — every token id, every logit, every CUDA kernel, every missing dictionary — describes that path. None of it describes a decision tree, an A* pathfinder, or a hand-written expert system, even though every one of those is, correctly and unremarkably, also called "AI."
The word was never precise. The mechanism always was — that's what the rest of this project actually measured.