Stand on a hilltop in the Peak District outside Macclesfield and look west, and you see the watermark of a culture whose flood-tide re-invented engineering, music, painting, writing and sport across the world, over a span of two centuries. You can see North-West autodidactism.

Engineering, at its best, is repeatable, testable, transferable between people because it's written down as a rule. That's exactly what the razor unit's makers had. What they didn't have was design judgement - the thing rooted in observation rather than specification, that knows when the rule has stopped serving the purpose it was built for. They applied technical rationality to a problem that needed reflection instead, and the result was an object with exact tolerances and n

"Systems thinking" has become the kind of phrase people add to their profile the way a small business adds "artisan" to a jar of jam. It's been emptied of meaning by people using it as a shield. So it's worth asking what it would actually mean, precisely, if the word still had edges.