Who Doesn't Understand Exponential Growth?


I don't know anyone who didn't understand exponential growth. Nobody is confused at why they get a big number when they hit the multiplication button on a calculator repeatedly. Nobody is confused at the lily pond example of exponential growth, or the chess board example, or the penny doubled everyday example.

I hear a lot about how Coronavirus "downplayers" just don't understand exponential growth. In my interaction with people, even lower intelligence people, I find this hard to believe.

Some people don't recognize exponential growth. For example, It's easy to overlook the money-making power of compound interest. I don't think this is what's going on though. The spread of disease is such a simple example of exponential growth. I haven't heard anyone contend that Coronavirus isn't spreading exponentially.

I think a lot of people don't adequately appreciate the speed of exponential growth, but that's different from not recognizing it's potential

I hear two positions that get mischaracterized as ignorant of exponential growth. The first is the position that notices not all exponential growth is unfettered. The second is the position that compares current death tolls for perspective.

A lot of people see exponential growth but realize that most of the things that we ever experience that grow exponentially stop before they consume the entire universe. Over two centuries ago Malthus asserted that human population would growing exponentially, and one day would inevitably lead to disaster. That was wrong.

Some people tell me Medicare is growing exponential and soon it will consume the entire economy. I'm skeptical. But it's condescending and idiotic to respond to my skepticism by claiming I must not understand exponential growth.

Mormons tell me the prophecy has been fulfilled because the Mormon church is growing exponentially. Clearly, we will all be Mormon soon, just do the math!

To take an example closer to COVID-19, it is true that Ebola once grew exponentially, until it didn't. Read NPR in September 2014:
"It's spreading and growing exponentially," President Obama said Tuesday. "This is a disease outbreak that is advancing in an exponential fashion," said Dr. David Nabarro, who is heading the U.N.'s effort against Ebola.
So what does this mean? If nothing changes in the next few weeks, we could see at least 60,000 cases by the end of 2014
Right now we've had more than 5,000 cases of Ebola"
That didn't happen. Something that grew exponentially and unconstrained at that rate should have infected all of us by the end of 2015. But it was constrained so it didn't happen either and it never will.

Exponential growth doesn't mean unfettered exponential growth. Most people don't know why Ebola didn't grow exponentially forever, but it's a fairly obvious observation that it didn't. It's a fairly obvious observation that almost nothing does. Why doesn't every infectious disease eventually infect everyone? You don't have to know why to know that they don't.

"But Coronavirus is different" Awesome, now explain why. Tell them Coronavirus how contagious it is. Tell them it has a high infection rate. Tell them we're less prepared. Tell them we let Coronavirus spread past the point of no return. Tell them it's too spread out and can't be contained. Tell them how Coronavirus is different such that its exponential growth will continue unfettered while other examples fizzled out, not that they don't understand exponential growth.



The other point of view that gets mischaracterized as ignorant of exponential growth is the one that makes current comparisons.

One will say something like, "for perspective, Coronavirus has killed 60,000, the flu kills 600,000/year. Snake bites kill 100,000/year" It's easy to infer that this person downplays the virus because they don't understand the potential mortality of Coronavirus. They don't understand exponential growth.

But there's another kind of person, the kind of person this downplayer is responding to. This person will say something like, "New York sees more deaths from Coronavirus than 9/11" or, "10,000 dead from Coronavirus, more fatalities than 6 world wars combined" or, "mom gets emotional recounting daughters Covid-19 death" These kinds of comparisons and stories exaggerate the current cost of Coronavirus, so others feel the need to give some perspective. They're not saying anything about the potential of the virus.

A few people genuinely don't understand exponential growth, or don't recognize that it's at play. But most of the time, when I dig deeper, I find that most people who are accused of this kind of ignorance actually take one of these other two perspectives; the one that suspects this exponential growth won't go on forever, and the one that is merely rebutting the people who exaggerate the current damage.

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