Notes on Scale by Geoffrey West

My good friend Jimi recommended to me the book ​Scale: The Universal Laws of Life, Growth, and Death in Organisms, Cities, and Companies by Geoffrey West. I found it very interesting from a nerdy scientific standpoint.

I enjoyed the discussions of fractals and complexity theory. My biggest major takeaways were all related to the scaling effects of life and biology and self-similarity around different species. The company stuff was also interesting, but less compelling from my standpoint (or maybe I've just read more in that department before), and the area I found least interesting was the city stuff, but it was still well written and had good information.

I definitely recommend this to anyone interested in biology and science/math in general. Below are my main notes and takeaways from the book.

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1 the big picture
8M life forms
Complexity
Commonalities between life and companies and cities 
Number of heartbeats same across life forms
Magic number 4
Global urbanization. Exponential expansion
Why cities remain while individuals and companies die
Energy key to metabolism for multiple purposes. Entropy kills. 
Size matters. Nonlinear scaling. 
Scaling and complexity. Emergence. Self-organization. Resilience. Adaptive dynamics. Where whole is different and more complex than just combo of cells. 
You are your networks. Power law. Power of 4 in exponent. 
Cities scale predictably

2 the measure of all things
Galileo
Fundamental constraints of scaling up organic things. Areas and volumes scaling. Collapsing under its own weight. Volumes increase much faster than areas. Strength and dissipating heat based on cross-sectional area. There are limits to scaling size and weight. Relative strength increases as size decreases. 
Orders of magnitude, logs, Richter scale. 
Drug dosages not scaling linearly. Scale with surface area not volume/weight. Scale by ⅔ exponent not linearly. 
Problems with classic BMI. 
Innovation and limits to growth. Innovation can change character and material and allow bypassing limits. 
Brunel. Engineer. 
Froude and modeling theory. Problems when scaling up physical designs of ships and railroads. Turbulence. 
Similarity and similitude. Dimensionless quantities like ratios. Pure numbers. 

3 simplicity, unity, and complexity of life
Metabolic rate
Natural selection
Simplicity underlying complexity. Metabolic rate similar across organisms. Economies of scale. Self-similar power laws. 32 factor increase in metabolic rate on log scale across organisms. Scale invariance. Fractal. Greater longevity for larger animals because more cells work less hard. 
Universality and magic number 4 that controls life. ¼ or ¾ exponents in growth. Amazing given variety in life. Allometric scaling
Energy. Emergent laws, hierarchy of life. ATP. Mitochondria. 
Networks and origins of quarter-power allometric scaling.
physics meets biology. Zeroth order estimate. Toy model. 
Network principles. 
Space filling
Invariance of terminal units
Optimization 
Impedance matching. Blood pressures same across animals regardless of scale. 
Self similarity and magic number 4. Fractals. Measuring lengths of borders. Wiggles on border fractals. Lengths increase with increasing resolution. It’s meaningless to quote a measurement without mentioning resolution of measurement. Fractal dimension measures wiggliness. Natural stuff isn’t perfectly smooth and Euclidean. Wiggles of stock market self similar fractal across all time scales. Higher fractal dimension healthier and more robust and elastic. 

4 the fourth dimension of life
Fractality gives extra fourth dimension. Fractal cross section and length measurements for fractal networks in bodies like respiratory network. Man-made things don’t have fractal dimensions. Cities and companies do. 
Why no mammals smaller than ants? 
Why hi mammals the size of Godzilla? Interface between capillaries and cells. 
Growth
We stop growing because maintenance of cells starts to match energy for creating them once we are big enough. ¾ exponent scaling metabolic rate. 
Universal growth equation across animals
global warming and exponential scaling of temperature
Everything about growth and death tied to average energy to activate an ATP molecule
Small temperature change increases metabolic stress much faster
Aging and mortality. Maximum human lifespan around 120. 1.5 billion heartbeats per life for all mammals. Caloric restriction lowers metabolic rate and increases lifespan

5 anthropocene to urbanocene
Exponentially expanding universe
Cities and global sustainability. 
Exponential growth. Constant or shortening doubling time. Quick demise in final generations of growth or descent. 
Rise of industrial city and discontents. 
Malthus and great innovation optimists
It’s all energy. 

6 A prelude to a science of cities
Are cities large organisms

7 toward a science of cities
Given city size alone, can predict accurately number of patents and disease and other metrics
Cities or fractals
Social and intellectual connections 

8 consequences and predictions
Cities speed up time
One hour rule: almost everyone travels to/from work 1 hour per day (no matter what method of transportation, so city size increases). Marketti’s constant. 
Increasing pace of walking with city size
Inverse square law for visitors to a site based on distance

9 toward a science of companies
Scaling rules apply to companies by power law. They’re self similar even across industries. Zip’s law. 
Myth of open ended growth. Companies will eventually die.
Companies die but cities don’t. Cities more decentralized and bottom up. Companies more centralized and top down. 

10 toward grand unified theory of sustainability
We are expanding superexponentially and have huge risk of things ending badly 

Afterword
Unified theory of science
Santa Fe institute. Complexity theory.