If you can't build something from first principles, you don't actually understand it. This principle—often associated with Richard Feynman, who could make quantum electrodynamics comprehensible to undergraduates not because he simplified it, but because he understood it completely—is direct and unforgiving: "What I cannot create, I do not understand."
This wasn't modesty—it was meant literally. If you can't reconstruct the argument, derive the equation, implement the algorithm, you're carrying someone else's conclusion around. That's fine for trivia. It's useless for innovation.
We take this seriously. Every course ends with working systems you built: a RAG pipeline querying your own documents, an evaluation harness testing your models, a Bayesian simulation running your assumptions. These aren't assignments to be graded and discarded. They're tools you own, understand, and can modify when your needs change.
The test isn't whether you can explain what embeddings are. It's whether you can build a retrieval system, diagnose why it's failing, and fix it. If you can't create it, you don't understand it. And if you don't understand it, you can't innovate with it.