Chesterton’s fence is the principle that reforms should not be made until the reasoning behind the existing state of affairs is understood. The quotation is from Chesterton’s 1929 book The Thing, in the chapter entitled “The Drift from Domesticity”:
In the matter of reforming things, as distinct from deforming them, there is one plain and simple principle;
a principle which will probably be called a paradox. There exists in such a case a certain institution or law;
let us say, for the sake of simplicity, a fence or gate erected across a road.
The more modern type of reformer goes gaily up to it and says, “I don’t see the use of this; let us clear it away.”
To which the more intelligent type of reformer will do well to answer:
“If you don’t see the use of it, I certainly won’t let you clear it away. Go away and think.
Then, when you can come back and tell me that you do see the use of it, I may allow you to destroy it. 1)
1) “Taking a Fence Down”. American Chesterton Society. Retrieved 21 June 2014.
I’ve seen Chesterton’s quote used or misused in ways that assume that an extant fence must have some use that is both ① still existent, and ② beneficial; and that it can only be cleared away if that use is overbalanced by some greater purpose.
But some fences were created to serve interests that no longer exist: Hadrian’s Wall, for one. The fact that someone centuries ago built a fence to keep the northern barbarians out of Roman Britain does not mean that it presently serves that purpose. Someone who observed Hadrian’s Wall without knowledge of the Roman Empire, and thus the wall’s original purpose, might correctly conclude that it serves no current military purpose to England.
For that matter, some fences exist to serve invidious purposes. To say “I don’t see the use of this” is often a euphemism for “I see the harm this does, and it does not appear to achieve any counterbalancing benefit. Indeed, its purpose appears to have always been to cause harm, and so it should be cleared away expeditiously.”
One big problem with Chesterton’s Fence is that since you have to understand the reason for something before getting rid of it, if it happens not to have had a reason, you’ll never be permitted to get rid of it.
Good point. Some properties of a system are accidental.
“We don’t know why this wall is here, but we know that it is made of gray stone. We don’t know why its builders selected gray stone. Therefore, we must never allow its color to be changed. When it needs repair we must make sure to use gray stone.”
“But gray stone is now rare in our country and must be imported at great expense from Dubiously Allied Country. Can’t we use local tan stone that is cheap?”
“Maybe gray stone suppresses zombie hordes from rising from the ground around the wall. We don’t know, so we must not change it!”
“Maybe they just used gray stone because it used to be cheap, but the local supplies are now depleted. We should use cheap stone, as the builders did, not gray stone, which was an accidental property and not a deliberate design.”
“Are you calling yourself an expert on stone economics and on zombie hordes, too!?”
“No, I’d just like to keep the wall up without spending 80% of our defense budget on importing stone from Dubiously Allied Country. I’m worried they’re using all the money we send them to build scary battleships.”
“The builders cared not for scary battleships! They cared for gray stone!”
“But it’s too expensive!”
“But zombies!”
“Superstition!”
“Irresponsible radicalism!”
“Aaargh … just because we don’t have the builders here to answer every question about their design doesn’t mean that we can’t draw our own inferences and decide when to change things that don’t make sense any more.”
“Are you suggesting that the national defense can be designed by human reason alone, without the received wisdom of tradition? That sort of thinking led to the Reign of Terror!”
That, and for certain kinds of fences, if there is an obvious benefit to taking one down, it’s better to just take it down and see what breaks, then maybe replace it if it wasn’t worth it, than to try and figure out what the fence is for without the ability to experiment.
Devils advocating that somethings are without reason and that is an exception to the rule is a fairly weak straw man.
Not having a reason is a simplification that does not hold up: Incompetence, apathy, out of date thinking, because grey was the factory default colour palette(credit to fubarobfusco), are all reasons. It is a mark of expertise in your field to recognize these reasonless reasons.
Seriously, this happens all the time! Why did that guy driving beside me swerve wildly, is he nodding off, texting, or are there children playing around that blind corner? Why did this specification call for a impossible to source part, because the drafter is using european software with european part libraries in north america, or the design has a tight tolerance and the minor differences between parts matter.
Not having a reason is a simplification that does not hold up:
What Chesterton actually said is that he wants to know something’s use, and if you read the whole quote it’s clear from context that he really does mean what one would consider as a use in the ordinary sense. Incompetence and apathy don’t count.
“Not having a reason” is a summary; summaries by necessity gloss over details.
I’ve seen Chesterton’s quote used or misused in ways that assume that an extant fence must have some use that is both ① still existent, and ② beneficial; and that it can only be cleared away if that use is overbalanced by some greater purpose.
Right, this is indeed a misuse. The intended meaning is obviously that you ought to figure out the original reason for the fence and whether it is still valid before making changes. It’s a balance between reckless slash-and-burn and lost purposes. This is basic hygiene in, say, software development, where old undocumented code is everywhere.
This is basic hygiene in, say, software development, where old undocumented code is everywhere.
Yep. On the other hand, in well-tested software you can make a branch, delete a source file you think might be unused, and see if all the binaries still build and the tests still pass. If they do, you don’t need to know the original reason for that source file existing; you’ve shown that nothing in the current build depends on it.
This is a bit of a Chinese Room example, though — even though you don’t know that the deleted file no longer served any purpose, the tests know it.
even though you don’t know that the deleted file no longer served any purpose, the tests know it.
Yes, if you solve the Chesterton fence of figuring out why certain tests are in the suite to begin with. Certainly an easier task than with the actual code, but still a task. I recall removing failed (and poorly documented) unit and integration tests I myself put in a couple of years earlier without quite recalling why I thought it was a valid test case.
On the other hand, in well-tested software you can make a branch, delete a source file you think might be unused, and see if all the binaries still build and the tests still pass.
Unfortunately, this doesn’t work outside software. And even in software most of it isn’t well tested.
Unfortunately, this doesn’t work outside software.
Sure it does—that’s how a lot of biological research works. Take some rats, delete a gene, or introduce a nutritional deficiency, etc. and see how the rats turn out.
I agree that the quote is vague, but I think it’s pretty clear how he intended it to be parsed: Until you understand why something was put there in the past, you shouldn’t remove it, because you don’t sufficiently understand the potential consequences.
In the Hadrian’s Wall example, while it’s true that the naive wall-removing reformer reaches a correct conclusion, they don’t have sufficient information to justify confidence in that conclusion. Yes, it’s obviously useless for military purposes in the modern day, but if that’s true, why hasn’t anyone else removed it? Until you understand the answer to that question (and yes, sometimes it’s “because they are stupid”), it would be unwise to remove the wall. And indeed, here, the answer is “it’s preserved for its historical value”, and so it should be kept.
But some fences were created to serve interests that no longer exist: Hadrian’s Wall, for one. The fact that someone >centuries ago built a fence to keep the northern barbarians out of Roman Britain does not mean that it presently >serves that purpose. Someone who observed Hadrian’s Wall without knowledge of the Roman Empire, and thus the >wall’s original purpose, might correctly conclude that it serves no current military purpose to England.
At the risk of generalizing from fictional evidence: This line of reasoning falls apart when it turns out that the true reason for the wall is to keep Ice Zombies out of your kingdom. Chesterton would surely have seen the need be damn sure that the true purpose is to keep the wildlings out, before agreeing to reduce the defense at the wall.
To say “I don’t see the use of this” is often a euphemism for “I see the harm this does, and it does not appear to achieve any counterbalancing benefit. Indeed, its purpose appears to have always been to cause harm, and so it should be cleared away expeditiously.”
Um, people generally don’t build fences to gratuitously cause harm.
Um, people generally don’t build fences to gratuitously cause harm.
That’s either trivial, or false.
It’s trivial if you define “gratuitously cause harm” such that wanting someone else to be harmed always benefits oneself either directly or by satisfying a preference, and that counts as non-gratuitous.
It’s false if you go by most modern Westerners’ standard of harm.
There was no reason to limit Jews to ghettos in the Middle Ages except to cause harm (in sense 2).
There was no reason to limit Jews to ghettos in the Middle Ages except to cause harm (in sense 2).
Er, this looks like a great example of not looking things up. Having everyone in a market dominant minority live in a walled part of town is great when the uneducated rabble decides it’s time to kill them all and take their things, because you can just shut the gates and man the walls. Consider the Jewish ghettoes in Morocco:
Usually, the Jewish quarter was situated near the royal palace or the residence of the governor, in order to protect its inhabitants from recurring riots.
When you tell people to look things up, be sure you first looked it up correctly yourself. That link says that ghettoes were used to protect Jews in the manner you describe. It does not say that that is why ghettoes were created.
Since I lost karma for that, I’d better elaborate. Your specific quoted line shows that protection was the reason for the ghetto’s placement, given that they were going to have one. It does not say that protection was the reason for having a ghetto.
Your own link says that “Jewish ghettoes in Europe existed because Jews were viewed as alien due to their non-Christian beliefs in a Christian environment”. The only mentionthat is anything like what you claim is halfway down the page, has no reference, does not name the location of the ghetto, and neither 1) says whether Jews could live only there or 2) if so, gives a reason for why they were prevented from living anywhere else.
That link says that ghettoes were used to protect Jews in the manner you describe. It does not say that that is why ghettoes were created.
It seems to me that we should separate the claim that the actual historical motivation of creating ghettoes was to cause harm to Jews, and the claim that there was no reason to make them besides causing harm to Jews. If there is one reason that Jews benefit from living separately from Christians or Muslims, then we can’t make the second argument.
But I don’t think we can make the first argument, because we can’t generalize across all Jewish quarters. In some cities, the rulers had to establish an exclusive zone for Jews in order to attract the Jews to move in, which suggests to me that this is a thing that Jews actively wanted. It makes sense that they would: notice that a function of many Jewish religious practices is to exclude outsiders and make it more likely for Jews to marry other Jews. Given the fact that Jews were on average wealthier than the local population and wealth played a part in how many of your grandchildren would survive to reproductive age, that’s not just raw ingroup preference. (Indeed, Jews moving from a city where a Jew-hating ruler had set up a ghetto to keep them separate might ask a Jew-loving ruler to set them up a ghetto, because they noticed all the good things that a ghetto got them and thought they were worth the costs.)
As for whether or not people voluntarily choose to segregate themselves, consider, say, Chinatowns in the US. Many might have been caused by soft (or hard) restrictions on where Asians could live, but I imagine that most residents stay in them now because they prefer living around people with the same culture, having access to a Chinese-language newspaper, and so on.
Notice what I said: to limit Jews to ghettoes. Voluntary segregation and creating Jewish areas to attract Jews does not limit Jews to ghettoes. In general, creating ghettoes to benefit Jews is not a reason to limit them to ghettoes. Furthermore, since I was using ghettoes as a counterexample, even if I had not phrased it that way voluntary segregation still wouldn’t count, because in order to have a counterexample it only need be true that some ghettoes were created to harm Jews, even if others were not.
The word “generally” in there is another of those things which makes a statement true and trivial at the same time. For one thing, it depends on how you count the fences (When you have a fence about not being a gay male and another about not being a lesbian, does that count as one or two fences?)
A more reasonable interpretation is to take “generally” as a qualifier for how wide the support is for the fence rather than for how common such fences are among the population of all fences—that is, there aren’t fences with wide support, the majority of whose supporters wish to cause harm. “Mandatory ghettoes” are indeed a counterexample to the statement when read that way.
There was no reason to limit Jews to ghettos in the Middle Ages except to cause harm (in sense 2).
The medieval allegations against Jews were so persistent and so profoundly nasty that they constitute a genre of their own; we still use the phrase “blood libel”. It seems plausible that some of the people responsible for the ghetto laws believed them.
They were entirely wrong, of course, but by the same token it may well turn out that Chesterton’s fence was put there to keep out chupacabras. That still counts as knowing the reason for it.
That falls under case 1. It is always possible to answer (given sufficient knowledge) “why did X do Y”. Y can then be called a reason, so in a trivial sense, every action is done for a reason.
Normally, “did they do it for a reason” means asking if they did it for a reason that is not just based on hatred or cognitive bias. Were blacks forced to use segregated drinking fountains for a “reason” within the meaning of Chesterton’s fence?
No, I don’t think it does. We can consider that particular cases of what we now see as harm may have been inspired by bias or ignorance or mistaken premises without thereby concluding that every case must have similar inspirations. Sometimes people really are just spiteful or sadistic. This just isn’t one of those times.
It seems clear to me, though, that Chesterton doesn’t require the fence to have originally been built for a good reason. Pure malice doesn’t strike me as a likely reason unless it’s been built up as part of an ideology (and that usually takes more than just malice), but cognitive bias does; how many times have you heard someone say “it seemed like a good idea at the time”?
It strikes me that one might simply presume the worst of whoever put up the fence. It was a farmer, for example, with a malicious desire to keep hill-walkers from enjoying themselves. I would extend the principle of Chesterton’s fence, then, to Chesterton’s farm: one should take care to assess the possible uses that it might have served for the whole institution around it as well as the motives of the man.
Chesterton’s fence is the principle that reforms should not be made until the reasoning behind the existing state of affairs is understood. The quotation is from Chesterton’s 1929 book The Thing, in the chapter entitled “The Drift from Domesticity”:
Wikipedia: Chesterton’s Fence
Prompted by this comment; curiously this appears to be lacking from rationality quotes threads despite some references to the fence around here.
I’ve seen Chesterton’s quote used or misused in ways that assume that an extant fence must have some use that is both ① still existent, and ② beneficial; and that it can only be cleared away if that use is overbalanced by some greater purpose.
But some fences were created to serve interests that no longer exist: Hadrian’s Wall, for one. The fact that someone centuries ago built a fence to keep the northern barbarians out of Roman Britain does not mean that it presently serves that purpose. Someone who observed Hadrian’s Wall without knowledge of the Roman Empire, and thus the wall’s original purpose, might correctly conclude that it serves no current military purpose to England.
For that matter, some fences exist to serve invidious purposes. To say “I don’t see the use of this” is often a euphemism for “I see the harm this does, and it does not appear to achieve any counterbalancing benefit. Indeed, its purpose appears to have always been to cause harm, and so it should be cleared away expeditiously.”
One big problem with Chesterton’s Fence is that since you have to understand the reason for something before getting rid of it, if it happens not to have had a reason, you’ll never be permitted to get rid of it.
Good point. Some properties of a system are accidental.
“We don’t know why this wall is here, but we know that it is made of gray stone. We don’t know why its builders selected gray stone. Therefore, we must never allow its color to be changed. When it needs repair we must make sure to use gray stone.”
“But gray stone is now rare in our country and must be imported at great expense from Dubiously Allied Country. Can’t we use local tan stone that is cheap?”
“Maybe gray stone suppresses zombie hordes from rising from the ground around the wall. We don’t know, so we must not change it!”
“Maybe they just used gray stone because it used to be cheap, but the local supplies are now depleted. We should use cheap stone, as the builders did, not gray stone, which was an accidental property and not a deliberate design.”
“Are you calling yourself an expert on stone economics and on zombie hordes, too!?”
“No, I’d just like to keep the wall up without spending 80% of our defense budget on importing stone from Dubiously Allied Country. I’m worried they’re using all the money we send them to build scary battleships.”
“The builders cared not for scary battleships! They cared for gray stone!”
“But it’s too expensive!”
“But zombies!”
“Superstition!”
“Irresponsible radicalism!”
“Aaargh … just because we don’t have the builders here to answer every question about their design doesn’t mean that we can’t draw our own inferences and decide when to change things that don’t make sense any more.”
“Are you suggesting that the national defense can be designed by human reason alone, without the received wisdom of tradition? That sort of thinking led to the Reign of Terror!”
That, and for certain kinds of fences, if there is an obvious benefit to taking one down, it’s better to just take it down and see what breaks, then maybe replace it if it wasn’t worth it, than to try and figure out what the fence is for without the ability to experiment.
Devils advocating that somethings are without reason and that is an exception to the rule is a fairly weak straw man.
Not having a reason is a simplification that does not hold up: Incompetence, apathy, out of date thinking, because grey was the factory default colour palette(credit to fubarobfusco), are all reasons. It is a mark of expertise in your field to recognize these reasonless reasons.
Seriously, this happens all the time! Why did that guy driving beside me swerve wildly, is he nodding off, texting, or are there children playing around that blind corner? Why did this specification call for a impossible to source part, because the drafter is using european software with european part libraries in north america, or the design has a tight tolerance and the minor differences between parts matter.
What Chesterton actually said is that he wants to know something’s use, and if you read the whole quote it’s clear from context that he really does mean what one would consider as a use in the ordinary sense. Incompetence and apathy don’t count.
“Not having a reason” is a summary; summaries by necessity gloss over details.
Right, this is indeed a misuse. The intended meaning is obviously that you ought to figure out the original reason for the fence and whether it is still valid before making changes. It’s a balance between reckless slash-and-burn and lost purposes. This is basic hygiene in, say, software development, where old undocumented code is everywhere.
Yep. On the other hand, in well-tested software you can make a branch, delete a source file you think might be unused, and see if all the binaries still build and the tests still pass. If they do, you don’t need to know the original reason for that source file existing; you’ve shown that nothing in the current build depends on it.
This is a bit of a Chinese Room example, though — even though you don’t know that the deleted file no longer served any purpose, the tests know it.
Yes, if you solve the Chesterton fence of figuring out why certain tests are in the suite to begin with. Certainly an easier task than with the actual code, but still a task. I recall removing failed (and poorly documented) unit and integration tests I myself put in a couple of years earlier without quite recalling why I thought it was a valid test case.
Unfortunately, this doesn’t work outside software. And even in software most of it isn’t well tested.
Sure it does—that’s how a lot of biological research works. Take some rats, delete a gene, or introduce a nutritional deficiency, etc. and see how the rats turn out.
I agree that the quote is vague, but I think it’s pretty clear how he intended it to be parsed: Until you understand why something was put there in the past, you shouldn’t remove it, because you don’t sufficiently understand the potential consequences.
In the Hadrian’s Wall example, while it’s true that the naive wall-removing reformer reaches a correct conclusion, they don’t have sufficient information to justify confidence in that conclusion. Yes, it’s obviously useless for military purposes in the modern day, but if that’s true, why hasn’t anyone else removed it? Until you understand the answer to that question (and yes, sometimes it’s “because they are stupid”), it would be unwise to remove the wall. And indeed, here, the answer is “it’s preserved for its historical value”, and so it should be kept.
At the risk of generalizing from fictional evidence: This line of reasoning falls apart when it turns out that the true reason for the wall is to keep Ice Zombies out of your kingdom. Chesterton would surely have seen the need be damn sure that the true purpose is to keep the wildlings out, before agreeing to reduce the defense at the wall.
Um, people generally don’t build fences to gratuitously cause harm.
That’s either trivial, or false.
It’s trivial if you define “gratuitously cause harm” such that wanting someone else to be harmed always benefits oneself either directly or by satisfying a preference, and that counts as non-gratuitous.
It’s false if you go by most modern Westerners’ standard of harm.
There was no reason to limit Jews to ghettos in the Middle Ages except to cause harm (in sense 2).
Er, this looks like a great example of not looking things up. Having everyone in a market dominant minority live in a walled part of town is great when the uneducated rabble decides it’s time to kill them all and take their things, because you can just shut the gates and man the walls. Consider the Jewish ghettoes in Morocco:
When you tell people to look things up, be sure you first looked it up correctly yourself. That link says that ghettoes were used to protect Jews in the manner you describe. It does not say that that is why ghettoes were created.
Since I lost karma for that, I’d better elaborate. Your specific quoted line shows that protection was the reason for the ghetto’s placement, given that they were going to have one. It does not say that protection was the reason for having a ghetto.
Your own link says that “Jewish ghettoes in Europe existed because Jews were viewed as alien due to their non-Christian beliefs in a Christian environment”. The only mentionthat is anything like what you claim is halfway down the page, has no reference, does not name the location of the ghetto, and neither 1) says whether Jews could live only there or 2) if so, gives a reason for why they were prevented from living anywhere else.
It seems to me that we should separate the claim that the actual historical motivation of creating ghettoes was to cause harm to Jews, and the claim that there was no reason to make them besides causing harm to Jews. If there is one reason that Jews benefit from living separately from Christians or Muslims, then we can’t make the second argument.
But I don’t think we can make the first argument, because we can’t generalize across all Jewish quarters. In some cities, the rulers had to establish an exclusive zone for Jews in order to attract the Jews to move in, which suggests to me that this is a thing that Jews actively wanted. It makes sense that they would: notice that a function of many Jewish religious practices is to exclude outsiders and make it more likely for Jews to marry other Jews. Given the fact that Jews were on average wealthier than the local population and wealth played a part in how many of your grandchildren would survive to reproductive age, that’s not just raw ingroup preference. (Indeed, Jews moving from a city where a Jew-hating ruler had set up a ghetto to keep them separate might ask a Jew-loving ruler to set them up a ghetto, because they noticed all the good things that a ghetto got them and thought they were worth the costs.)
As for whether or not people voluntarily choose to segregate themselves, consider, say, Chinatowns in the US. Many might have been caused by soft (or hard) restrictions on where Asians could live, but I imagine that most residents stay in them now because they prefer living around people with the same culture, having access to a Chinese-language newspaper, and so on.
Notice what I said: to limit Jews to ghettoes. Voluntary segregation and creating Jewish areas to attract Jews does not limit Jews to ghettoes. In general, creating ghettoes to benefit Jews is not a reason to limit them to ghettoes. Furthermore, since I was using ghettoes as a counterexample, even if I had not phrased it that way voluntary segregation still wouldn’t count, because in order to have a counterexample it only need be true that some ghettoes were created to harm Jews, even if others were not.
Azathoth123 said that people generally don’t build fences to gratuitously cause harm, not that they never ever do.
The word “generally” in there is another of those things which makes a statement true and trivial at the same time. For one thing, it depends on how you count the fences (When you have a fence about not being a gay male and another about not being a lesbian, does that count as one or two fences?)
A more reasonable interpretation is to take “generally” as a qualifier for how wide the support is for the fence rather than for how common such fences are among the population of all fences—that is, there aren’t fences with wide support, the majority of whose supporters wish to cause harm. “Mandatory ghettoes” are indeed a counterexample to the statement when read that way.
The medieval allegations against Jews were so persistent and so profoundly nasty that they constitute a genre of their own; we still use the phrase “blood libel”. It seems plausible that some of the people responsible for the ghetto laws believed them.
They were entirely wrong, of course, but by the same token it may well turn out that Chesterton’s fence was put there to keep out chupacabras. That still counts as knowing the reason for it.
That falls under case 1. It is always possible to answer (given sufficient knowledge) “why did X do Y”. Y can then be called a reason, so in a trivial sense, every action is done for a reason.
Normally, “did they do it for a reason” means asking if they did it for a reason that is not just based on hatred or cognitive bias. Were blacks forced to use segregated drinking fountains for a “reason” within the meaning of Chesterton’s fence?
No, I don’t think it does. We can consider that particular cases of what we now see as harm may have been inspired by bias or ignorance or mistaken premises without thereby concluding that every case must have similar inspirations. Sometimes people really are just spiteful or sadistic. This just isn’t one of those times.
It seems clear to me, though, that Chesterton doesn’t require the fence to have originally been built for a good reason. Pure malice doesn’t strike me as a likely reason unless it’s been built up as part of an ideology (and that usually takes more than just malice), but cognitive bias does; how many times have you heard someone say “it seemed like a good idea at the time”?
Has been posted before, more than once.
It strikes me that one might simply presume the worst of whoever put up the fence. It was a farmer, for example, with a malicious desire to keep hill-walkers from enjoying themselves. I would extend the principle of Chesterton’s fence, then, to Chesterton’s farm: one should take care to assess the possible uses that it might have served for the whole institution around it as well as the motives of the man.
It has appeared before, twice. Maybe it should have a Wiki article here.
Appears every two years… when tho old quotes are two far down in the search results I guess.
Done: http://wiki.lesswrong.com/wiki/Chesterton%27s_Fence