>> Mechanism holds that every aspect of the world can be represented as a simple hierarchical structure of entities. But, while useful in fields like mathematics and manufacturing, this idea is generally worthless, because most aspects of the world are too complex to be reduced to simple structures.

>Without trying to manage complexity, it becomes impossible to build real systems.

Both of you are correct. The real world is too complex to be modeled, and without trying, you can't build a real system. The answer to the conundrum that real systems include humans, which can handle the hard-to-model parts.

The author appears to be using bombastic language to communicate what is actually a simple point. I see the technique used often. There's a method to the madness. It's the long-form version of "to get someone to give you a correct answer on the Internet, post a wrong answer rather than just ask." Spiritual books are often written like this. Without a blend of the overly pedantic and the utterly simple, the reader won't be compelled to dissect what the author has written and won't have the intended epiphany where the reader discovers it wasn't as simple as he thought.