Since HN is populated with literalists, I will clarify here that this obviously does not mean that all aspects of reality are created by consensus. The Earth will not unroll and flatten itself out given a sufficient number of Flat Earthers. By "reality", they mean that a suprisingly large subset of what we consider "the world" is actually human level authored truth.
Some examples:
* Janet is a police officer.
* Dave is a criminal.
* France owns the Mona Lisa.
* France is a country.
* Idaho is not a country.
* Lance Armstrong is a cyclist.
* Bats are not birds.
* You can buy a car for $20,000.
In all of these examples, the fundamental process that determines the truth or falsehood of those statements is consensus. I can hear you already. "If you don't get a paycheck from the city, you aren't a cop." "You aren't a criminal unless you are convicted by the legal system." "The Mona Lisa is literally in the Louvre." "Bats are mammals, in order chiroptera. All birds are in class aves." "If I give someone the money, I will literally have a car that I can drive around."
For literal-minded folks like us, the idea that key properties of what we consider cold hard objective reality is in fact just squishy agreement can be unsettling. Hell, half of us got into computers specifically to avoid hand-wavey subjectivism.
But it's true. If you root cause any of those statements, you will eventually bottom out on "some people agree on it". There is no ground truth below human consensus on any of these and many many many more critical, tangible facets of our lives.
Tech folks will spend a truly Herculean effort to avoid this uncomfortable reality. They really really want things to feel solid. I look at the entire blockchain enterprise as essentially that. A boondoggle to try to subtract the humans out of human-constructed reality. But as this article shows, it is always doomed to failure. If you want your tech to actually do anything, then it has to interact with humans. And those humans will only choose to act in accordance with your tech if they believe the reality that it claims. Which means ultimately it is their belief that defines what the blockchain means, and not vice versa. Consent is always at the bottom.