I read, with interest, Robert C. Martin´s comment on Justin Searl´s critique of a common TDD teaching approach. Strange it was to see “the good uncle” to be so upset about Justin´s article. Why does he take it so personally, it seems, that someone is not content with the state of TDD-affairs? Why salting Justin´s earth? Anyway… what I wanted to express is my disagreement with Robert C. Martin´s idea of a “Domain Discontinuity”. He proposes there to be two levels in software system design: one, where thinking before implementing is good, and another one where it´s bad. The first being architecture, the second being “the problem domain”.