Sunday, October 1, 2017

Book Review: Scale

Scale: The Universal Laws of Life and Death in Organisms, Cities, and Companies
Geoffrey West
Science

With a subtitle like that, you expect that "modest" is not going to be what you get. And you don't.

In most of these reviews, I try to avoid too much recapping of what the book's contents actually are. That's what the back-cover blurb is for. For Scale, however, my reaction only makes sense in the context of Geoffrey West's argument. So, briefly:

  1. It's long been known that larger animals have slower metabolic rates--lower heartbeats, longer lives, and so forth.
  2. Empirically, the relationship between animal size and metabolic rate is a three-quarters power law
  3. Many other biological features also show three-quarter-power scaling, or one-quarter-power scaling, or occasionally one-half-power scaling.
  4. Geoffrey West has come up with a theoretical explanation for this surprising profusion of multiples of 4.
  5. This theory allows him to make testable, quantitative predictions for various biological features, which agree closely with observations.
  6. Cities have some animal-like features, but they also have some differences. For example, the number of patents per capita more than doubles when a city doubles in size.
  7. With some alterations, West's theory can be used to make somewhat looser predictions about cities. 
  8. Companies also can be compared to organisms.
  9. With some further alterations, Wests theory can be used to make somewhat looser yet predictions about companies.
My reaction is: intriguing, but unproven. For one thing, West isn't necessarily the first to have made the connections he makes, although he may well be the first to do so in a formal, testable fashion. For another, his ideas seem quite strongly supported in the biological realm, but increasingly speculative outside it. For a third, some of the non-biological examples smell a bit like fishing. By that I mean that any two quantities that both grow exponentially--say, the adoption of telephones after 1880 and the salaries of baseball free agents after 1980--will have some power-law relationship, and some of these relationships will fit with whatever theory you propose.

That doesn't mean I didn't like the book; I did. It reminds me of Edward O. Wilson's Consilience. (Wilson is a better writer, but West makes his case more convincingly.) There's also a close connection to Edward Glaeser's very good book Triumph of the City, and a more distant one to the outstanding The Ghost Map by Stephen Johnson. 

The connection here, if it wasn't obvious, is that these are all big-picture-thinking books: books that try to perform synthesis on a heroic scale, making sense of many disparate facts under one intellectual umbrella. Scale isn't the best such book I've ever read--I wouldn't recommend it to a reader who doesn't have some tolerance for scientific writing, for example--but it's pretty good. In particular, it's a paean to the value of interdisciplinary thinking, and that's a subject dear to my heart.

6 comments:

  1. It sounds like a great read. I'm curious about the relevance of the ratios and patterns, however. People are good at spotting patterns. And we really like to find reasons for events, outcomes, etc. We are astounded by coincidences, even when they're not that unlikely, and we want to find the cause.

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    1. Well . . . these are a little more than just patterns. These are actual highly-statistically-significant correlations in the data. You may remember from your basic biology that the smaller an animal, the faster its heart beats? It turns out that's an extraordinarily strong correlation in the data, so strong that it's really not plausible as a coincidence. West demonstrates a ton of similarly strong, and similarly-scaled, correlations. Proportion of white to gray matter in animal brains. Biomass production of insect communities. Temperature dependence of life span. Etc., etc. It's only logical to suspect that when all of these strong correlations pop out, and they all have roughly the same slope and shape, that there's some connection among them.

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  2. I'm sure it is true for animal hearts. And of course, I haven't read the book. I'm sure you are familiar, however, with the very strong correlation between the number of Nicholas Cage movies per year and the number of people who drown in swimming pools. I'm just saying www.tylervigen.com/spurious-correlations

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    1. As a data science guy, I dare say I'm tolerably familiar with it. What West is talking about isn't like that. A correlation between Nicolas Cage movies and drowning is prima facie dubious. A strong nonlinear correlation between a city's size and its crime rate, number of patents generated, etc. etc. etc. begs to be explained.

      To expand a bit, nobody would be surprised if you found out that doubling a city's size doubles the number of patents it generates. Only that's not true. Doubling a city's size more than doubles the number of patents it generates. That's true, broadly, no matter what size you're talking about. It's also true of a great many other city metrics--and, more impressively, the exponent of the increase is very similar across metrics.

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    2. OK, so now I'm interested in reading the book, or one of the others you recommend. Scientific writing puts me to sleep, even if the subject is as genuinely interesting as you describe. It is a flaw, I suppose.

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    3. Not a flaw, just a fact. Certain kinds of writing put me to sleep (Jane Austen, I'm looking at you). Scale is written reasonably well--not in High Academic, but in English--but it might be a little strong for you. I'd start with The Ghost Map and, if that interests you, move on to Triumph of the City.

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