Durable dynamic systems have elements, or layers, that change at different rates. The fast layers that change quickly provide the innovation, while the slower layers stabilise and remember.

In his short article Pace Layering: How Complex Systems Learn and Keep Learning, Stewart Brand gives this evocative example of the time hierarchy of a coniferous forest:

"Take a coniferous forest.  The hierarchy in scale of pine needle, tree crown, patch, stand, whole forest, and biome is also a time hierarchy.  The needle changes within a year, the crown over several years, the patch over many decades, the stand over a couple of centuries, the forest over a thousand years, and the biome over ten thousand years.  The range of what the needle may do is constrained by the crown, which is constrained by the patch and stand, which are controlled by the forest, which is controlled by the biome.  Nevertheless, innovation percolates throughout the system via evolutionary competition among lineages of individual trees dealing with the stresses of crowding, parasites, predation, and weather.  Occasionally, large shocks such as fire or disease or human predation can suddenly upset the whole system, sometimes all the way down to the biome level."

It's an example of his wonderful framework of pace layers which he applies as the working structure of a robust and adaptable civilisation.

Time hierarchy

The rule of 7 is an idea in marketing that it can take hearing a message 7 times before we might take action.

Apparently the rule is from early movie marketing and while I don't know if I'd rely on the number it certainly seems a sensible idea to keep in mind that you can't expect people to take action the first time they hear your message — if you're trying to get people to try something new be it buying food, downloading your app, watching a movie, or a choosing an electric car, it takes a while and repeated exposure before you can expect it to pay off.

I can't remember where I heard it, but some advice I keep in mind when communicating is that by the time you're tired of saying it, others are just starting to hear it. It's not a bad thing to repeat your main message.

I learned about the Rule of 7 from the recent book Human Powered by Trenton Moss.

When putting an apple in the adverts on this sketch I was reminded that so often it's the things in the supermarket that are most healthy for us that don't get anyone shouting about them at all.

The rule of 7

I'd never heard the words flotsam and jetsam used in any way but together so had always assumed it was a term to mean general debris floating in the water or washed up. It turns out they have distinct meanings that also affect how they're treated by law.

Flotsam, from flotter to float, refers to debris accidentally lost or washed overboard, often from a shipwreck or accident.

Jetsam is debris that was deliberately jettisoned by a boat in distress, likely to try and lighten the load.

Being that flotsam was lost accidentally, under maritime law, it can be claimed by the original owner, but jetsam can be claimed by the person who found it.

The rubber duck in the sketch refers to the story of the thousands of rubber ducks that washed overboard (flotsam) in the Pacific ocean in 1992. Over the next 25 years, the ducks found themselves washed ashore all across the world revealing much of the ocean's currents as one giant connected system.

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Flotsam and jetsam