The Shannon Number, and the impossible hubris of city planning.
Consider for a moment a simple chessboard. 8×8, or 64 alternately colored squares, occupied by 32 pieces, of only 6 categories of pieces. In 1950, a man named Claude Shannon published an influential article entitled “Programming a Computer for Playing Chess” which is credited with fathering the field of computer chess.
Within this article, Shannon posited a number, which was an estimated lower bound on the number of legal chess positions, roughly put at 10^43. The upper bound in a theoretical chess match was roughly 10^50, and the total game-tree complexity was estimated at 10^120, now called the Shannon Number. In other words, the number of possible positions that any number of chesspieces could be in at any given point in a theoretical chess match falls somewhere between 10^43 and 10^50. The number of possible games two theoretical players could play without repeating themselves is somewhere in the neighborhood of 10^120. By comparison, the most common estimate for the number of atoms in the observable universe is somewhere around 10^80.
Think about that for a moment. Chess is theoretically more detailed, in terms of game-tree complexity, than the observable universe is in terms of atoms. Now consider the limitations imposed on the game of chess. The pieces may not move beyond their 8×8 square. The pieces may only move in certain directions. One piece must be moved per turn. Only one piece may occupy a single spot. Chesspieces have no feelings, no motivations, no impulses.
The reason I bring this up is because today, November 8, is World Town Planning Day, according to a group of people who are far too arrogant for their own good. They apparently do not see any problem with telling urban dwellers how to live their lives, despite the inherent complexity of the undertaking being far beyond that which even the sharpest mind could comprehend, let alone calculate. In a world where we have no computer powerful enough to determine the exact number of possible unique games of chess, we nevertheless have a group of “city planning” enthusiasts who feel like they are smart enough to control the minutiae of millions of human lives from the top down.
Amazing advances have been made in computer chess. Using retrograde computer analysis, one can fairly accurately pick a winner in a chess game in which only 6 or 7 of the original 32 pieces remain on the board. World champion Garry Kasparov has been defeated by supercomputers in the past. However, no matter how much city planners want to treat the city’s residents as pawns in their little game, they will never encounter a single person with as many limitations as a chesspiece. People have feelings. People make stupid decisions, smart decisions, innocuous decisions. People can immigrate and emigrate. People can act and fail to act.
Even the smallest city, when populated by humans, will never be able to be planned. The philosophical foundations for city planning are exactly the same as those which underpinned Marxism and Soviet-style socialism. The idea that things can be planned from the top down is always proven spectacularly wrong.
City planning as a discipline is an arrogant, pseudoscientific fraud. Its practitioners are the intellectual equivalents of astrologers but with real opportunity to do lasting damage to other, innocent people. “World Town Planning Day” should be consigned to the dustbin of history.
***As an aside, I am by no means the first to tread this ground. If you’re interested in the folly and failures of city planning at all stages, take a gander at Blight Ideas by David Willens, Best Laid Plans by Randal O’Toole, and many books by Thomas Sowell.