I think the point here is that there is a really bad "rhetoric smell" to A City is Not a Tree. It's a geeky rant which jumps to conclusions and makes tendentiou

I think the point here is that there is a really bad "rhetoric smell" to A City is Not a Tree. It's a geeky rant which jumps to conclusions and makes tendentious statements. Christopher Alexander's trajectory as an architect (almost all other architects ignore his work) is witness to this. Whether it's down to the abstract formalism, messianism, narcissism, I don't quite know. But there is something off-putting about him. When Alexander tries to sell us the line that a city "is" a semilattice, and that this precise mathematical formalism is somehow humane while an equally abstract tree is not—these abstract structures are being asked to do a lot of work. A more skilled theorist wouldn't structure the argument around platonic ideas. All he is trying to say is that exclusive zoning is bad, that human settlements are a naturally a mess of overlapping activities and concerns and should be designed that way. Trying to suggest that this is some kind of mathematical property just feels theological and immature. His writing is reminiscent of a CS undergrad coming up with a concept for a new operating system based on some particular abstraction (pipes, say) and writing a long screed about it without implementing the thing. It's giddy and the central idea is an overvalued abstraction. All I can say is, Alexander is a crank, as far as architecture goes.