The advantage of old things

In this video, a curator at The British Museum explains that the worn-down hilt of an Anglo-Saxon sword shows that it was beloved and meant a lot to its owner. An old sword, well-used and shabby, is dependable. It has experience, and it’s not afraid to leave its youth behind.

I think this is a case in which survivorship bias becomes a useful tool. When deployed correctly, we can be proud of what has survived because survival itself is an indicator of quality. Other considerations like how shiny it is becomes secondary.

The story of statistician Abraham Wald recognizing this in World War II bombers is legendary in rationalist circles:

You don’t want your planes to get shot down by enemy fighters, so you armour them. But armour makes the plane heavier, and heavier planes are less manoeuvrable and use more fuel. So, there must be an optimum amount of armour, what is that?

Wald was given data from officers at war – the distribution of bullet holes on planes that retuned from Europe. The damage wasn’t uniformly distributed across the aircraft, with more bullet holes in the fuselage and not so many in the engines.

The armour, said Wald, doesn’t go where the bullet holes are. It goes where the bullet holes aren’t.

The reason planes were coming back with fewer hits to the engine is that planes that got hit in the engine weren’t coming back at all.

We have to be careful not to be over-reliant on this, though. Sometimes, old and worn-down things can simply signify that they need to be replaced. However, it is crucial to recognize the converse: the things in life that show the most wear-and-tear are sometimes the most resilient.