Software engineering is a relatively immature field. Nobody knows how to cook it in a proper way. What we know for sure is how to fail (point of the article). There was an analogy about building bridges and writing software. Building a bridge is boring, it's a very mature engineering field, and it's clearly known how to do it the best way possible. Software development is far from it. Unknown unknowns, ever changing requirements, different mental models in people's brains...