Some things scale well.
Double their size and you get double the output (or more). Other things don’t, and my God is it important to know which is which.
Let me tell you about Robert Wadlow.
He was enormous, the largest human ever known.
A pituitary gland abnormality bombarded Wadlow’s body with growth hormone, leading to staggering size. He was six feet tall at age seven, seven feet tall by age 11, and when he died at age 22 stood an inch shy of nine feet tall, weighed 500 pounds, and wore size 37 shoes. His hand was a foot wide.
He was what fictional stories would portray as a superhuman athlete, capable of running faster, jumping higher, lifting more weight and crushing more bad guys than any normal person. Like a real-life Paul Bunyan.
But that was not Wadlow’s life at all.
He required steel leg braces to stand and a cane to walk. His walk wasn’t much more than a limp, requiring tremendous effort.
What few videos of Wadlow exist show a man whose movements are strained and awkward. He was rarely seen standing on his own, and is usually leaning on a wall for support.
So much pressure was put on his legs that near the end of his life he had little feeling below his knees. Had Wadlow lived longer and kept growing, casual walking would have caused leg bones to break.
What actually killed him was nearly as grim: Wadlow had high blood pressure in his legs due to his heart’s strain to pump throughout his enormous body, which caused an ulcer, which led to a deadly infection.
You can’t triple the size of a human and expect triple the performance – the mechanics don’t work like that. Huge animals tend to have short, squatty legs (rhinos) or extremely long legs relative to their torso (giraffes). Wadlow grew too large given the structure of the human body.
There are limits to scaling.Writing before Wadlow’s time, biologist J.B.S. Haldane once showed how many things this scaling issue applies to.
A flea can jump two feet in the air, an athletic human about five. But if a flea were as large as a man, it would not be able to jump thousands of feet – it doesn’t scale like that.
Air resistance would be far greater for the giant flea, and the amount of energy needed to jump a given height is proportional to weight. If a flea were 1,000 times its normal size, its hop might increase from two feet to perhaps six, Haldane assumed.
Look around and this concept is everywhere, in every direction.
A man coming out of a bath carries with him a film of water of about one-fiftieth of an inch in thickness. This weighs roughly a pound. A wet mouse has to carry about its own weight of water. A wet fly has to lift many times its own weight and, as everyone knows, a fly once wetted by water or any other liquid is in a very serious position indeed.
Eyes are similar. Vision occurs when light hits rods and cones in the back of your eyes.
The rods and cones are roughly the diameter of a lightwave. They cannot be smaller, because an image can’t be defined in a unit smaller than a wave of light, or larger, as vision detail would diminish.
Animals with tiny eyes, like mice, tend to have poor vision with rods and cones the same size as ours, just fewer of them. Then, beyond a certain size, gains diminish.
An African elephant weighs 14,000 pounds and its eyes are 3.5 centimeters wide. An adult human might weigh one-hundredth as much and its eyes are … 3 centimeters wide.
“For every type of animal there is a most convenient size, and a change in size inevitably carries with it a change of form,”
A most convenient size.
A proper state where things work well, but break when you try to scale them into a different size or speed.
Which, of course, also applies to business and investing.
Photo credit: Samuele Errico Piccarini on Unsplash