Chesterton's Fence, Explained With a Garden Gate

The first week in our house, I decided the garden gate was badly designed. It had a heavy spring on it that dragged it shut with a clank every time anyone went through. I'm not fond of clanking. So one Saturday I unhooked the spring, set it on the shed shelf, and felt rather pleased with myself.

By Monday afternoon the gate was ajar, a neighbour's very friendly dog was in the back garden, and my herb bed looked as though it had been audited by a small bulldozer. The spring had been there to keep the gate closed. That was all. The reason was sitting in plain sight and I hadn't looked for it, because I'd already decided the thing was a nuisance.

That small, muddy lesson is most of what people mean by Chesterton's fence: if you come across a fence and can't see why it's there, don't pull it down until you've found out. The idea comes from G.K. Chesterton, an English writer, who put it in a 1929 book called The Thing. I'm paraphrasing from memory of how it's usually told, so treat the wording as mine, not his.

What is Chesterton's fence?

Chesterton imagined a reformer who comes across a fence or gate across a road. The reformer says, "I can't see the use of this. Let's clear it away." Chesterton's reply, put plainly, is that if you can't see the use of it, you're in no position to remove it yet. Go away and find out why it was built. If you come back and can explain its purpose, then you can have a sensible conversation about whether to take it down.

Notice what he is not saying. He isn't saying the fence is good, or that old things are wise, or that nothing should ever change. He is making a point about order: understand first, then decide. Not seeing a reason is a fact about you and where you're standing. It is not a fact about the fence.

That distinction is the one people most often get wrong. The idea is sometimes quoted as a defence of "leave everything as it is". It's closer to a rule of good manners towards the past: ask before you act.

Why can't we see the reason in the first place?

This is the part I find most interesting, and it took me a while to see it.

A fence that works leaves no evidence of its work. Think of a fence that keeps a flock safe from a hazard. When it's doing its job, nothing happens. The sheep stay put, and the hazard stays on the far side. Everything you can observe is a quiet field with a bit of wire in the way. The problem it solved never shows up, because it was prevented.

So the usual situation is lopsided. The cost of a fence is visible: it's in your way, it looks untidy, it clanks. The benefit is invisible, because the benefit is an absence. If you only count what you can see, almost every working fence will look like a poor bargain.

You can run a small thought experiment. Imagine a town where a levee has held back a river for forty years. A newcomer looks at the big, ugly mound and thinks it blocks a nice view. Nobody under forty has seen the river on the wrong side of it. The levee's success is exactly what makes it look pointless. The newcomer isn't foolish. They are simply working from the evidence available to them, and the evidence has been quietly edited by the fence itself.

A backyard example: the odd little wall on the slope

Here is a garden case that's a little less obvious than my spring.

Suppose you buy a house with a sloping back lawn. Halfway down, there's a low line of timber sleepers, perhaps knee-high, running across the grass. It holds back nothing you can see. It's in the way of the mower. You'd like a flat, open lawn, so you plan to lift it out.

Before you reach for the crowbar, it's worth a few minutes of looking:

• Look at the ground on either side. Is the soil higher on one side than the other, even slightly? A step in the level suggests the timber is holding earth in place.
• Look at where water goes. After rain, stand there and watch. Does the wall slow water, spread it, or turn it away from the house or a path?
• Ask someone. A neighbour who has lived on the street for years often knows what the previous owners dealt with. In my case a neighbour had the answer to the gate in a single sentence, which would have saved me a weekend and a herb bed.

You might find that the wall is quietly stopping soil from creeping downhill, or slowing runoff after heavy rain. Or you might find nothing at all: the ground is level, the water behaves, and the timber is only there because someone once fancied a terrace and gave up halfway. Either answer is useful. In the first case, you've saved yourself a problem. In the second, you can pull it out with a clear conscience.

A workplace example: the form field nobody likes

The same shape turns up indoors. Imagine a small team that processes deliveries. Their form has a box labelled "date received" that everyone fills in and nobody enjoys. It seems redundant, since the system already stamps a date when the form is submitted. A newcomer proposes deleting it to save a few seconds per form.

A few weeks later, someone in another part of the business can't match invoices to deliveries. It turns out the "date received" box, which is the date the goods physically arrived, often differs from the date the form was typed in, and a colleague downstream had been quietly relying on it. The box wasn't pointless. Its use just happened to live in a different room.

I've made this example up to show the pattern. It's a common one, though, and anyone who has worked with shared processes will recognise some version of it. Software people have a close cousin of the habit. A programmer who finds a strange-looking line of code often checks the history of the file and the notes left with each change, to see why it was added before removing it. It is the same instinct as asking the neighbour about the sleepers: someone knew something, so find out what.

How do you find out why a fence is there?

You don't need to turn into a detective. A few modest steps usually do it, roughly in order of effort:

1. Look closely at what the thing actually does. What does it hold, block, separate, or connect? What is on each side?
2. Ask the people nearest to it. Long-serving colleagues, neighbours, the person who handed the job over to you. Ask kindly and without suspicion. "I'm trying to understand why this is here" is a friendly question, and people often enjoy answering it.
3. Check for records. Old emails, handover notes, building plans, the history of a document or file.
4. Ask what would happen if it vanished. Run it forward in your head. Who would notice, and when?
5. If it's safe, try a reversible test. Prop the gate open for a day. Leave the form field optional for a fortnight. Reversible experiments are a gentler way of asking the question than demolition.

Match the effort to the stakes. A garden gate deserves ten minutes. A load-bearing wall deserves a professional. I'm still learning to tell which is which, and I don't always judge it well.

When can the fence actually go?

Here I want to be honest, because Chesterton's fence can be misused as a reason never to change anything, and that isn't what it's for.

Sometimes, after genuine looking, the fence really can go. There are a few ways that happens:

• The reason has expired. A gate built to keep a particular animal in is no use once the animal is gone. Notice, though, that you only learn this after finding the purpose. That is the whole point of the exercise.
• The reason was never a good one. People build things out of habit, haste, or a misunderstanding. Finding the "why" doesn't oblige you to agree with it.
• The cost of keeping it outweighs what it protects. Some fences do their job, but at a price that's no longer worth paying.
• Looking has its own cost. If something is cheap and easy to put back, spending a week investigating it may be more effort than simply trying the change and watching. A reversible experiment is often the better form of investigation.

There's also a real limit I can't tidy away: sometimes you look honestly and the answer isn't there. The person who built it has moved on, the records are gone, and nobody remembers. Then you have to make a judgement under uncertainty, and the idea can't make that judgement for you. What it can do is nudge you towards caution where the change is hard to undo, and towards freedom where it's easy to reverse.

I'd add one more worry, which I haven't resolved. It's easy to feel the pull of "I don't know why it's there, so it must be important", and that can be just as lazy as "I don't know why it's there, so it must be useless". Both skip the looking. The fence isn't an argument for keeping things. It is an argument for being curious first.

A fence worth wondering about

I put the spring back on the gate, and I've since come to rather like the clank. It sounds like the herbs being safe.

What I keep wondering about is the fences I've built myself. Every habit, rule, and tidy system I've put in place had a reason on the day I made it. Years on, I could not tell you what half of them are for. If someone new arrived in my life and asked, would I have an answer? It makes me think a good gift to a future stranger, or to a future me, might be a small note on the fence: this is here because...

So the next time something looks pointless to you, perhaps pause for a moment before deciding. What might it be quietly holding back? And which of your own fences have you forgotten you built?