Known recipe, unreadable result.
How to train a model is well understood: architecture, data, an optimization rule. What comes out is not a program a person can read. These systems are grown more than they are built — the growing conditions are set by hand, the grown thing is not. There is no line of code that says if X, then Y — only billions of learned numbers whose joint behavior produces the answers.
Looking inside these systems, what we see are vast matrices of billions of numbers. These are somehow computing important cognitive tasks, but exactly how they do so isn’t obvious. Dario Amodei, The Urgency of Interpretability, 2025
This is the black box problem: full control over the growing conditions, weak insight into the grown thing. Not a bug someone will patch next quarter — a structural property of how these systems come to exist.