I think part of it is they’re logical fallacies. For instance, the scientific consensus on climate change is not technically proof of climate change; rather, it’s all the observations, statistics, etc. that are the evidence for climate change. Thus, it is true that claiming an argument is true solely because of scientific consensus is indeed a logical fallacy, as logical fallacies are relating to, well, logic.
For all practical purposes, however, we live in a complex world with lots of uncertainty, and we can generally trust expert consensus if for no other reason than they’re more likely to understand the facts of a certain technical matter better than us, and thus more likely to be able to ascertain the truth. And when discussing complex, technical concepts, I’m generally going to trust expert consensus so long as I am reasonably assured that they are indeed experts and that they have no systemic conflict of interest.
Our cities would be compact, walkable, jam-packed with quality transit, and nearly car-free. Cargo would be transported with cargo ebikes, barges along rivers and canals, local freight rail, and cargo trams. People would move by foot and bike and trams and metro and high-speed rail.
The surrounding countryside would be home to ecological, sustainable smallholder agriculture, preferably with plenty of technology for efficient precision agriculture. Instead of massive monocultures of corn, we’d have diverse polycultures of dozens of different crops, both annuals and perennials.
Nature would be abundant, protected, and rewilded. We would remove most roads into wild areas and replace with trains and velomobile trails, which would be much lower impact on wild habitats. Every city would have easy, rapid transit access to natural areas by rail, so anyone can go hiking or exploring or whatever they like.
Our economy would be centered around productivity, not rent-seeking and speculation. We would use policy to reduce barriers to entry to create highly competitive markets. We would heavily tax externalities like carbon emissions and fertilizer runoff and PFAS contamination.
We would tax people on what they take, not what they make. Income taxes? Nah, you did the labor; that value should belong to you. Carbon emissions? That materially harms others so you should pay tax on that. Hoarding valuable god-given land? You didn’t make it, so you should pay taxes on the land you deprive from the rest of humanity.
Our democracy would be reformed with a much better voting system like mixed-member proportional representation (MMPR) or single transferrable vote (STV), so we could have healthy multiparty systems.
Our society would publicly invest more in research and development, open-source projects, infrastructure, and anything else that generates positive externalities. You rewilded 100 acres of native grassland? Society should pay you for your valuable labor.
The balance of power between labor and employers would be balanced. A citizen’s dividend or universal basic income, subsidies on positive externalities (like rewilding), and the economic general growth spurred by elimination of rent-seeking would allow for an empowered working class that could capture its own productivity gains, demand better pay, and demand shorter hours. Much like how the professional class can demand good pay and good working conditions currently.
In short, the economy would be centered around Georgist principles, environment and agriculture around permaculture, and democracy around technocratic and representative democracy. A shared, sustainable prosperity for all.