[Supermancho]

> when all the people who have a theory of a given program stop working on it. It dies.

This is only true of software of a particular level of complexity. For the most part, it simply isn't true. Humans made it (who also would routinely forget details about their own project) and humans can understanding it enough to build a working theory. If you can perform tests for something, you can deduce what it's doing, although the business case of why or specific experience with other approaches resulting in failures is often not recoverable by deduction.

[deely3]

As I understand you mean that author used word "theory" instead of "intention"?

Why, why they used word "theory" in the first place?