11 March 2020

How Exponential Growth Boggles the Mind

Somebody picks up on a problem in the pond. Lily pads are growing rapidly. By their calculations, they're doubling every day to cover more and more of the pond.

Assume that it takes 30 days for the pads to cover the whole pond. Someone who has been hollering about this problem for 25 days sounds shrill for a simple reason: on day 25 lily pads cover only 3% of the pond. From day 1 to 25, lily pads have only grown from a tiny fraction to 3.1%. Double that 5 more days, though, and you're looking at 100% coverage - enough to choke out the pond.
We don't have good intuition for exponential growth.

In related news, a week ago Italian hospitals were able to give each coronavirus patient high-quality care. Today they are practicing triage. Not everyone who comes into the ER is getting treatment - even some folks who are dying for reasons unrelated to the coronavirus. They simply haven't the capacity.

1 comment:

Quaker in a Basement said...

There's a little more to it than just being unable to comprehend exponential growth. Our world gives us limited experience with unrestrained growth.

In the world we live in, growth of lily pads in your pond probably wouldn't continute to grow at the same rate until the pond was covered. One or both of the following would be likely: the nutrient powering the runaway growth of lily pads would be depleted; or the lily pad would become attractive food for some other organism.

We're ill-equipped to understand unrestrained growth because we rarely experience it.