Chesterton's fence put simply is: Don't take a fence down unless you know why it was put up.

It is tempting, in a spirit of progress, to want to do away with old designs, laws, policies, or institutions that no longer help. To think, perhaps, that the people that made them weren't maybe as smart as we are, or seeing things in the right way. Yet institutions, policies, or fences, weren't usually made by accident — they require effort and action, even putting up a fence. Chesterton's fence, after GK Chesterton, is a reminder that before we remove the old and perhaps replace it with the new we would do well to at least understand why the original was put in place.

Once we understand why the fence was there in the first place if we still think it's of no use, then by all means pull it down.

Read more on Chesterton's fence, including its origins.

Chesterton's fence

The curb-cut effect illustrates how when we design to benefit disadvantaged or vulnerable groups we end up helping society as a whole.

Angela Glover Blackwell explains how campaigning by students with disabilities in Berkeley in the early 1970s led to adding curb cuts to the Berkeley sidewalks to make access easier for those in wheelchairs. Yet it wasn't just people in wheelchairs that it helped. Curb cuts also made life easier for people pushing children in strollers, people using trolleys for deliveries, people pulling a suitcase, those wheeling bikes or on skateboards, and it also helps save lives by guiding people to cross at safe locations.

Another example is adding closed captioning to TV that helps anyone watch in a noisy bar, a waiting room, or watching an airline safety video. Or a classic example of universal design in the OXO Good Grips range originally made to be comfortable for holding a peeler even if you have arthritis.

It's also a useful analogy for "how laws and programs designed to benefit vulnerable groups, such as the disabled or people of color, often end up benefiting all," (PolicyLink) whether that be increasing broadband access, improving public transport or taking cuts out of curbs.

Here's a short, fun video of Gary Karp explaining the curb-cut effect.

Thanks to my patron Quintin Balsdon for sharing it with me.

The curb-cut effect

Also known as Brandolini’s Law, this is the simple observation that it’s far easier to produce and spread BS, misinformation and nonsense than it is to refute it.

In fact, the iSchool at University of Washington launched a course on Calling Bullshit with the first class being booked up within one-minute of registration. The professors, Carl Bergstrom and Jevin West have since written a book: Calling Bullshit: The Art of Skepticism in a Data-Driven World.

Phil Williamson in Nature also wrote a nice article emphasizing that we should take the time and effort to correct misinformation where we can. In it, he proposed the idea that “The global scientific community could…set up its own, moderated, rating system for websites that claim to report on science. We could call it the Scientific Honesty and Integrity Tracker, and give online nonsense the SHAIT rating it deserves.”

The BS asymmetry principle

People are complicated. Life is complicated. Ecosystems are complicated. And despite our best efforts or intentions, we have a remarkable history of messing things up in unexpected ways.

One simple theory for why this may be is that unintended consequences are likely to happen whenever we try to regulate a complex system by using a simple system. This so often happens in any kind of large-scale or government attempt to control something within a complex system using relatively simple programs, regulations, laws, policies or other actions. Things will happen that we didn’t anticipate.

A policy of suppressing forest fires that goes on to cause even greater fires.

An attempt to reduce traffic in Bogotá by restricting who could drive each day based on licence plates that led people to simply buy more cars.

More open workplaces that cause people to behave more privately.

Elimination of predators that leads to the proliferation of grazing animals and a reduction in diversity.

The effects of literally any dam built anywhere.

Or social distancing policies that results in outdoor natural spaces being crammed with people at weekends.

Often, as with some of these, the outcome can be the opposite of what you intended, known as the cobra effect. Controlling complex systems is difficult.

The law of unintended consequences

You might think that adding more of a good thing would make things better. And, yes, that’s often true, up to a point. However, the law of diminishing returns suggests that as you add more of a single factor, you are likely to yield progressively lower benefits.

It’s like the old adage, “Too many cooks spoil the broth.” Another cook or two might help, but beyond that, they’ll probably start getting in each other’s way. Aside from cooking broth, you might see the law play out in spending on advertisements, quality improvements in production or your wealth.

And we should also never forget that “more is different”.

The sketchplanation is a homage to perhaps my favourite comedy sketch with an early-career Simon Pegg in the series Big Train: the cake factory (video). Well worth two and a half minutes.

Law of diminishing returns

Kind of a Goodhart’s law with more explanation, Campbell’s law, rather pessimistically suggests:

The more any quantitative social indicator is used for social decision-making, the more subject it will be to corruption pressures and the more apt it will be to distort and corrupt the social processes it is intended to monitor.

It pretty much seems to work with everything, unfortunately. If you measure the performance of an employment office by the number of cases handled you may get quick but ineffective placements and interviews. If, instead, you measure them on number of persons placed in jobs you may unintentionally drive a focus on placing the simplest cases at the expense of those who most need the service.

When customer support is measured by number of tickets dealt with I’ve heard of writing quick answers that don’t fully solve a question in the knowledge that the customer will soon come back with another ticket to solve.

When policing effectiveness is judged by crimes reported and the number of unsolved cases you may get both under reporting of crimes, and a form of plea bargaining where a criminal may be encouraged to confess to extra crimes — therefore fewer unsolved cases — in exchange for more lenient sentences. Campbell notes that:

It seems to be well documented that a well-publicized, deliberate effort at social change–-Nixon’s crackdown on crime–-had as its main effect the corruption of crime-rate indicators, achieved through underrecording and by downgrading the crimes to less serious classifications.

Measuring schools on attendance encourages creative reasons for children being taken out of school. Assessing learning can quickly become teaching to, and cramming for, the test. When reviews come to dominate purchase decisions pressure increases for fake reviews.

And then there’s elections and voting…

Campbell, Donald, Assessing the Impact of Planned Social Change, Dec 1976. (pdf)

HT: Benjamin Baker who shared it with me when I posted about Goodhart. Also, for alternative sides to what gets measured gets better there’s Seth Godin’s take on Campbell’s law: Speedometer confusion, and Scott Carter’s pithier paraphrasing of Campbell’s law: “What gets measured, gets corrupted.”

Campbell’s law

For years, I’ve wondered at how as a kid I found the monkey bars in a playground (often a jungle gym in the US) so much easier to swing on than I do as an adult. And I see our kids swinging around easily on them, while now it’s hard for me just to hang off them. The reason why is partly to do with the square-cube law.

The square-cube law is the deceptively simple observation that as you scale up dimensions — say, as you get taller — then area of the object increases proportional to the square of the length, while volume increases proportional to the cube of length. This fundamental relationship has enormous significance in the sizes and shapes of animals and the limits of how big trees can get and how big we can build our bridges and buildings.

Because the strength of our bones, muscles or wooden beams is proportional to their cross-sectional area, this means that while the strength of a larger object, assuming the same proportions as the smaller one, increases according to the square of a length, the weight (from the volume it takes up) increases according to the cube of a length. So, relative strength decreases as size increases.

Some corollaries are therefore that children’s small size relative to the area of their muscles and bones makes them relatively stronger than adults and so they can more easily support their weight as they swing on the monkey bars. In the same way, press ups are harder for bigger people than they are for smaller. And while an ant has tiny spindly legs, those legs could easily support 50 other ants of its size, whereas for an elephant to support its own weight it needs chunky legs — not spindly ones — and there’s no chance it could get close to carrying 50 other elephants on its back.

It’s also part of the reason short trees can be spindly, but big sequoias have relatively chunkier trunks, and we need increasingly strong materials to build bigger and bigger skyscrapers compared to the shed in your garden.

Galileo discussed this back in 1638 and it still requires some getting your head around today.

For this and other fascinating insights of scaling check out Scale, by Geoffrey West.

The Square-Cube law

Conway was mostly observing software development, but I would think it has some application to any large project: cruise ship design, car design, space shuttle design, heck maybe even governments and law.

Law is kind of a strong word for an observation, but in any case, here are some other ‘laws’: Fitt’s law, Metcalfe’s law, Goodhart’s Law, Muphry’s law, Moore’s law, Koomey’s law, the law of diminishing brownies, the law of lockers and, my favourite, Hofstadter’s Law.

PS: As you read this I may be cycling mid-lake and trying not to sink to raise money for charity: www.cycleorsink.com

Conway’s Law

The value of a telecommunications network is proportional to the square of the number of users of the system.
— Robert Metcalfe

This law explains a little of the remarkable power of a growing network. Each time you add a user, or node, to the network, the number of connections increase in proportion to the square of the number of users. So, in this simple example where every new node gets a connection to each of the existing nodes, you can see that, say, adding a single node to an 11 node network creates 11 new connections.

It’s a simplified example because in most networks the value is not directly proportional to the number of connections as some connections or users may be more valuable than others, and usually adding a new user wouldn’t create a connection to all existing users — say if it was in a different country, or people spoke a different language, or just cared about different things. But nevertheless, you can see how a network quickly becomes valuable as users join.

So, Facebook has about 2 billion users…

Metcalfe was talking about telecommunications networks and the basic proposition has been modified since it was formulated including by Metcalfe himself.

Once again, just because something is called a law doesn’t mean it is one. See Fitt’s Law

Metcalfe’s Law

In other words, if you pick a measure to assess people’s performance, then we find a way to game it. I like the illustration of a nail factory that sets number of nails produced as their measure of productivity and the workers figure out they can get tons of tiny nails. And, if they switch it to the weight of nails made, they get a few giant heavy nails. Or perhaps the story of measuring fitness by steps from a pedometer only to find they get put on the dog.

Some strategies for helping this are to try and find better, harder to game measures, assess with multiple measures, or to allow a little discretion. More detail in this nice little article.

I also liked an idea I read in Measure What Matters of pairing a quantity measure with a quality measure, for example, assessing both number of nails and customer satisfaction of the nails.

Goodhart’s Law: when a measure becomes a target, it cease to be a good measure.

A variation of Murphy’s law whereby if you happen to be criticizing someone else’s spelling or grammar you’ll have a mistake yourself. Or should that be criticising?

Muphry’s Law

Update: More recent research has brought into question the captivating notion of ego depletion with difficulties reproducing some key experiments and suggesting other factors may be at work.

In his book You are now less dumb, David McCraney explains an concept called ego depletion with the basic idea that our brains require fuel, particularly the decision-making and glucose hungry pre-frontal cortex. Every time you have to make decisions or deal with difficult situations it tires you such that we have a sort of finite amount of will power. If you spent the morning battling to get the kids dressed and out the door, then jostling your way through a crowded commute, by the time you get to work you’re more likely to say ‘whatever’ to any decisions that come your way. Making decisions is hard work.

McCraney brings up a remarkable, and slightly disturbing, study by Shai Danziger which followed eight Israeli judges as they decided on over 1,000 parole applications. The findings show that prisoners were most likely to be granted parole first thing in the morning, after a snack break, and right after lunch. If you were unlucky enough to be up for parole just before lunch, bad luck.

If you want the most control over your own mind so that you can alter your responses to the world instead of giving in and doing what comes naturally, stay fresh. Take breaks. Get some sleep. And until we understand what ego depletion really is, don’t make important decisions on an empty stomach.

Here’s a nice summary of Shai Danziger’s parole study in the Economist including a remarkable chart.

Don’t make important decisions on an empty stomach

Translation: The energy efficiency of computers doubles roughly every 18 months.

In a new twist beyond Moore’s Law, which shows signs of reaching it’s limits, there’s Koomey’s Law. In his own words, the idea is:

“…at a fixed computing load, the amount of battery you need will fall by a factor of two every year and a half.”

Why does this matter? It means we can fit more more computing power into smaller and smaller devices. Which is much of the reason the phone in your pocket is probably more powerful than the EDVAC there in the chart.

Koomey’s Law

This chart is from the original he published - just the five data points. Pretty simple huh? The “observation, originally made in 1965, that the number of transistors on an integrated circuit would continue to double every year. Although this increase has slowed to a doubling in eighteen to twenty four months, Moore’s law has held true for nearly fifty years and is the foundation for the astounding Information Technology revolution we see around us.”

For those interested in Moore’s law, remarkably, I think the best information is my Dad’s book, The Computing Universe, which is also the source of the quote.

Moore’s Law

The time to a target depends on the ratio of distance to the target over it’s size. So clicking on a small target close by might take a similar time to clicking on a large target further away. It’s a simple model and there are a few little games out there to bring it home in practice.

I’m reminded however, of an observation from a mentor of mine, Darrell Mann, that just because people call it a law doesn’t mean you have to treat it like one. The example of Apple’s standard program icons at the base of the screen that expand when you mouse near them, are a simple technique that help to overcome the limitations of Fitt’s law. There are plenty more. Don’t be sucked in to laziness by a name.

Fitts’ Law

Hofstadter's Law is one of my favourites.

“It always takes longer than you expect, even when you account for Hofstadter’s Law.”

Sketchplanations tagged with law