You wrote this, and I just saw it, so I took up your request:
An interesting exercise: to what extent was transportation a binding constraint on the size of premodern towns/cities? (One number you may want: Braudel (pg 121) estimates that 5000 square meters of land growing wheat would provide one person-year of food, not accounting for crop rotation.) Leave a comment if you try a calculation here; I’m curious to see how other peoples’ models compare to my own.
My general model is that a town or city cannot at all function as a cohesive urban entity if it takes longer than a day to traverse. If a journey from an edge home to a central production facility (and back) consumes each day, then the person in that home can’t actually work in the facility.
If cars go 80 miles per hour, a city with a diameter of >160 miles is probably geo-economically “taut” as you put it, and close to its limits. (These will tend to have to be on an ocean or navigable river to give them access to global food markets.)
I checked with Google Maps just now. From Cuautitlán Izcalli to San Pedro Mártir via public transit through the center of Mexico City takes ~3 hours. From Santa Clarita to San Juan Capistrano through LA by car takes ~2 hours. These are probably modern functional “town sizes” for people who greatly value “an exurban home”, and engage in “moderately productive centralized labor coordinating with a huge labor pool to achieve extreme specialization” on most work days.
The same basic idea, interacting with agricultural productivity as a constraint, doesn’t limit “the city based on food”, but changes what specific agricultural uses are optimal in surrounding rings around a market center (where prices will typically be most accurate, such as to allow arbitrage opportunities to be noticed back before telegraph) when planting strategies are optimized based on the transport cost characteristics of the foodstuffs.
In the idealized case you get circles around the market.
In practice (with rivers, roads, and mountains) you get “isoclines” of cost or time or time-as-part-of-cost. The importance of locating cities at the mouth of a navigable river falls our of this from first principles <3
This thinking framework was famously started by Von Thunen (who wanted to optimize agricultural practices on a german hacienda, basically) who is arguably the “founding father” of a field called economic geography.
Chisholm’s Rural Settlement and Land Use is maybe a bit dry, but it aptly applies the tools of the field to include relatively modern updates (like the effects of current global prices being known around the planet and cheap transcontinental shipment) and generates resulting maps showing a good match between theory and practice, with vast areas of the globe acting like food production basins for major global population centers.
(Learning about economic geography was a big part of how I realized that “zoning laws” are not even really necessary to get “zones of similar production”. All you need is cheap switching costs on land use, and local sanity, and it should mostly just “all coase out” in the end.)
I think modern knowledge workmight be turning the internet and its various online language communities into “one big virtual city”, where the barriers to making such a thing truly work probably occur in “communication travel time” or some such… perhaps related to psychologies of trust, intellectual coordination, shared languages, the latency and publicness of important broadcasts, maybe percolation theory applied to gossip networks, and maybe also some Dunbar issues?
Presumably the Sage of Omaha noticed this and noticed that he wanted to live where he was born, and could do so, maybe treating his home location as an input into his emotional and intellectual stability? This only could work for him after having learned value investing via physical co-presence on the east coast from Benjamin Graham, and then heading back to Nebraska to systematically apply his brain to information according to certain algorithms without the “distractions of NYC”?
But I think it is notan accident that he went to a huge central place, then filtered like crazy to find a good teacher, then learned the algorithms early in life that he could apply from anywhere, then went off to a non-central city to make money simply by very precisely “knowing things about how to turn precise knowledge into money”.
You wrote this, and I just saw it, so I took up your request:
My general model is that a town or city cannot at all function as a cohesive urban entity if it takes longer than a day to traverse. If a journey from an edge home to a central production facility (and back) consumes each day, then the person in that home can’t actually work in the facility.
If cars go 80 miles per hour, a city with a diameter of >160 miles is probably geo-economically “taut” as you put it, and close to its limits. (These will tend to have to be on an ocean or navigable river to give them access to global food markets.)
I checked with Google Maps just now. From Cuautitlán Izcalli to San Pedro Mártir via public transit through the center of Mexico City takes ~3 hours. From Santa Clarita to San Juan Capistrano through LA by car takes ~2 hours. These are probably modern functional “town sizes” for people who greatly value “an exurban home”, and engage in “moderately productive centralized labor coordinating with a huge labor pool to achieve extreme specialization” on most work days.
The same basic idea, interacting with agricultural productivity as a constraint, doesn’t limit “the city based on food”, but changes what specific agricultural uses are optimal in surrounding rings around a market center (where prices will typically be most accurate, such as to allow arbitrage opportunities to be noticed back before telegraph) when planting strategies are optimized based on the transport cost characteristics of the foodstuffs.
In the idealized case you get circles around the market.
In practice (with rivers, roads, and mountains) you get “isoclines” of cost or time or time-as-part-of-cost. The importance of locating cities at the mouth of a navigable river falls our of this from first principles <3
This thinking framework was famously started by Von Thunen (who wanted to optimize agricultural practices on a german hacienda, basically) who is arguably the “founding father” of a field called economic geography.
Chisholm’s Rural Settlement and Land Use is maybe a bit dry, but it aptly applies the tools of the field to include relatively modern updates (like the effects of current global prices being known around the planet and cheap transcontinental shipment) and generates resulting maps showing a good match between theory and practice, with vast areas of the globe acting like food production basins for major global population centers.
(Learning about economic geography was a big part of how I realized that “zoning laws” are not even really necessary to get “zones of similar production”. All you need is cheap switching costs on land use, and local sanity, and it should mostly just “all coase out” in the end.)
I think modern knowledge work might be turning the internet and its various online language communities into “one big virtual city”, where the barriers to making such a thing truly work probably occur in “communication travel time” or some such… perhaps related to psychologies of trust, intellectual coordination, shared languages, the latency and publicness of important broadcasts, maybe percolation theory applied to gossip networks, and maybe also some Dunbar issues?
Presumably the Sage of Omaha noticed this and noticed that he wanted to live where he was born, and could do so, maybe treating his home location as an input into his emotional and intellectual stability? This only could work for him after having learned value investing via physical co-presence on the east coast from Benjamin Graham, and then heading back to Nebraska to systematically apply his brain to information according to certain algorithms without the “distractions of NYC”?
But I think it is not an accident that he went to a huge central place, then filtered like crazy to find a good teacher, then learned the algorithms early in life that he could apply from anywhere, then went off to a non-central city to make money simply by very precisely “knowing things about how to turn precise knowledge into money”.