text:
Talk:Right of self-defense

Where are the challenges to the right of self-defense?
There is no mention here of the universal religious prohibition against killing. Although many religions today condone self-defense, they all seem to contradict the apparently absolute condemnations from Moses, Jesus, Buddha, and Gandhi, not to mention the immense literature dedicated to pacifism and non-violence that implicitly contradicts or qualifies the right to self-defense.

The other omitted problem is that the definition of self-defense varies from state to state, and from person to person, especially among those who are undergoing some form of stress.

It is hard to think of a war that was not started for reasons of self-defense. This calls for a section on the common misuse of the doctrine.

Could the right of self-defense be a shibboleth like war itself, an ancient and very convenient belief that has gone on too far without critical examination? 04:03, 4 February 2016 (UTC) — Preceding unsigned comment added by Bdubay (talk • contribs)

Protecting others – 2004
I have a question about the self-defence law. Is it considered self-defence if you are protecting a friend? If my friend was being attacked and I killed his assailant, would it be considered self-defence? Could I still go to jail? - [68.82.208.62 at 01:23, 15 March 2004] --- Shouldn't this be merged with [Self-defence]?

Your answer is on the "Article Tab" on this page. I'll paste it here for you.

Self-defense law in England English law provides for the right of people to act in a manner that would be otherwise unlawful in order to preserve the physical integrity of themselves or others or to prevent any crime. It is provided in both common law and more specifically in the Criminal Law Act (1967). If such a defence is proved to the satisfaction of the court then the person is fully acquitted of the charges against them.

The act of protection must fulfill a number of conditions in order to be lawful. The defendant must believe, rightly or wrongly, that the attack is imminent. While a pre-emptive blow is lawful the time factor is also important, if there is an opportunity to retreat or to obtain protection from the police the defendant should do so - demonstrating an intention to avoid violence. However the defendant is not obliged to leave a particular location even if forewarned of the arrival of an assailant.

The other key factor is reasonableness - the defendants response must be necessary and in proportion to the nature of the attack. The harm inflicted on the assailant must not exceed the harm being avoided by the defendant. However like immanency the nature of the defence rests on the defendant's belief, whether their actions were in proportion to the circumstances they believed existed.

"Defence of others" is US centric
While I agree that "Defence of others" belong in this article, I think that section is very US centric. I'm no legal expert but it seems to me that many passages are directly refering to US law and courts. A clean-up is needed. --J-Star 06:41, July 20, 2005 (UTC)

Police shootings at the 2001 EU-summit
Scott Sanchez added the following material to the page, which I'm not sure fits within the tone of the article, and may require an article of its own. I brought it here to seek a consensus as to whether it should be returned to the article, or moved elsewhere. -- BD2412 talk 21:01, July 21, 2005 (UTC)
 * Actually it was I that added it but that's beside the point. I added it as an example of how the sections above have been used in a real case. However I can agree that it's a bit long-winded and breaks the style of the article. I won't mind if it is left out. --J-Star 21:48, July 21, 2005 (UTC)
 * I concur it disrupts the flow of the article - if we put in real-life examples for every jurisdiction the article would be unreadable. Tufflaw 05:16, July 22, 2005 (UTC)
 * How about a one-line link to a separate article in the rioting that accompanied the EU summit? -- BD2412 talk 05:00, July 31, 2005 (UTC)

 * In 2001, during the EU-summit in Gothenburg, heavy rioting broke out. On June 15, a group of police officers became subjected to heavy attack from stone throwing rioters and were forced to retreat. One of the officers was knocked unconscious and his colleagues stopped retreating in order to defend him, drawing their sidearms. They fired several warning-shots into the air. Despite this, one rioter kept up the attack and two of the defending officers fired for effect. The rioter was hit by one bullet and was seriously injured but survived.

 * A criminal investigation was started. This investigation found that no crime had been committed and was suspended. It was later re-opened twice and then closed again with the same conclusion.

 * The reasoning was the unconcious officer had been perceived by his colleagues as being in life threatening peril. The defending officers were assisting him, therefore receiving the same rights as the unconscious officer. And even though other police officers had arrived on the scene behind the defending party by the time the shots were fired, the investigators found that the defending officers had been under such stress that they had completely focused on the rioters in front of them and therefore not noticed the reinforcements. Because of this, while the actual stiuation was not as severe as the defending party percived it to be, the subjective peril was such that the defending officers were not to be charged with committing a crime.

Nonsense?
To the person that removes mentions of statute law repeatedly: in countries based on civil law, statute law states that self-defense and defense of others are acceptable legal excuses provided that the means of defense used are proportional to the offense (however, typically, what is meant by "means proportional to the offense" is typically left for courts to decide).

By the way, you're not supposed to repeatedly remove content without at least some discussion on the talk page. David.Monniaux 05:27, 25 July 2005 (UTC)

Criminal Template
I don't know much about templates, but is it possible for the article to carry both the criminal and tort law templates positioned in a sensible way? If not, I think the crimlaw template would be more appropriate.

Self-defence and the Right to Life
This article seems a little unclear to me. For one, the right to self-defence in the united states is generaly understood to be an exercise of your right to life, just like publishing a news paper is an exercise of your right to free speech; I don't see this mentioned in the article. In general, the article gives the impression that self-defence is a result of governments not doing a great job of defending the population, leaving the people to fend for themselves. Maybe I'm wrong. -- Dullfig 22:31, 31 January 2006 (UTC)

 * This page is about the general principle and does not refer to individual countries. Your point would be relevant to self-defense (United States) when you could epxlore the constitutional issues relevant only to the U.S. And people have always been allowed to defend themselves no matter how effeicient the government, because the government cannot be everywhere all the time. David91 03:01, 1 February 2006 (UTC)

Fighting words
In some jurisdictions, the aggressor may lose the ability to argue self-defense by speaking provocative words. See, e.g., Vaughn v. State, 17 Ala. App. 383, 84 So. 879 (1920); Wheatley v. State, 93 Ark. 409, 125 S.W. 414 (1910); People v. Barnard, 208 Ill. App. 3d 342, 567 N.E.2d 60 (mere words enough), appeal denied, 139 Ill. 2d 598, 575 N.E.2d 917, 159 Ill. Dec. 110 (1991); McCarty v. Commonwealth, 244 Ky. 413, 51 S.W.2d 249 (1932); State v. Ball, 262 S.W. 1043 (Mo. 1924); State v. Council, 129 S.C. 116, 123 S.E. 788 (1924); Smith v. State, 965 S.W.2d 509 (Tex. Crim. App. 1998); Scott v. Commonwealth, 143 Va. 510, 129 S.E. 360 (1925). THF 10:48, 9 July 2007 (UTC)

 * Interesting... 🤔 Someone who's wrong on the internet (talk) 03:27, 19 March 2023 (UTC)

Proposal for merger of Make My Day State
As Make My Day State is largely unreferenced, I'm not sure about merging it into Self-defense, which itself needs a lot of improvement. As this article seems like the best umbrella article, I think Make My Day State should be merged into this one. --Evb-wiki (talk) 15:03, 22 December 2007 (UTC)

response: “Make my day state” is a common term in law enforcement and legal circles, not to mention the gun lobby. It really deserves a listing in its own right in the hope that others will append references to newspaper articles and legal precedent references. --Jasburger (talk) 16:13, 26 December 2007 (UTC)

Article moved from Self-defense (theory)
I found this after noticing that, until a few minutes ago, there was no article on the "right of self-defense."

I moved this article there because it isn't as common to call it a "theory."
 * "theory of self-defense"
 * "right of self-defense"
 * "right to self-defense"

Without renaming it, it would be impossible to integrate this article with the template and the  template. Otherwise, I would've had to create "right of self-defense," as a separate article, which would've basically been a silly POV fork. There's no reason to create a new article when this one right here is already a mess. ☯ Zenwhat (talk) 10:52, 25 January 2008 (UTC)

Proposed merger
I'd like to get to work merging the following articles into this one:
 * Right to bear arms
 * Make My Day Law
 * Make My Day State

I was going to just expand this article and merge those last two POV forks into this one, but then it occurred to me that it would be impossible for me to expand this article in a way that wouldn't be redundant.

Since the broader topic is the "right of self-defense," and the right to bear arms is just a small sub-set of that, then this article should be larger than Right to bear arms, but right now it's the other way around.

Much of the content in Right to bear arms isn't just discussing the right to bear arms, but the right of self-defense overall. I.E., English common law and John Locke didn't just argue for people to have the right to own weapons, but the broader right to defend themselves, which was why they had the right weapons. So, Right to bear arms should be a sub-section (or perhaps a description in the lead?) while all of the information in Right to bear arms should be merged here. ☯ Zenwhat (talk) 19:04, 28 January 2008 (UTC)

 * Merge. Right to bear arms should be a subset of right of self-defense. Yaf (talk) 19:16, 28 January 2008 (UTC)
 * Bearing arm(s) has a different meaning than Right to bear arms.  Bearing arms can refer to hunting or poaching, or simply carrying a weapon, as well as being a euphemism for serving in military service.  In contrast, Right to bear arms refers to the right of self-preservation and self-defense.  A Right to bear arms never implies a right to hunt or poach, or a right to serve in the military. Yaf (talk) 21:35, 28 January 2008 (UTC)
 * Yaf, Your opinion runs contrary to Joyce Lee Malcolm, plus many others. Could you point to your sourcing please?  Thanks.  SaltyBoatr (talk) 22:00, 28 January 2008 (UTC)
 * Malcolm does not advocate a right to poach. Nor does Malcolm advocate a right that one  must be accepted into the military.  You misinterpret Malcolm. Yaf (talk) 13:30, 29 January 2008 (UTC)
 * Per Malcolm, if you were a Protestant, under a Catholic King, in late 17th Century England, yes the right to bear arms meant that you had a right to belong to the militia. And, also per Malcolm, the disarmament that lead to the Bill of Rights of 1689 had very much to do with the gentry not wanting the commoners using their militia weapons (and gunpowder) to hunt for meat on their 'privileged' land.  Have you read the Malcolm book?  SaltyBoatr (talk) 14:56, 29 January 2008 (UTC)
 * As I said previously, you are misinterpreting Malcolm. Restoration of the Right to Bear Arms for Protestants did not suddenly give all Protestants the right to poach on a manor's game.  And, in late 17th Century England, the Right to Bear Arms meant that you had the right to be armed to serve in the militia, not that the muster captain had to take you.  You are misinterpreting the concept of "Right" and the point of the "Right".  Yaf (talk) 15:43, 29 January 2008 (UTC)
 * Please identify the page number and quote, I would like to read that for myself, thanks. SaltyBoatr (talk) 15:54, 29 January 2008 (UTC)

 * Strong Oppose Notice that "bear arms" means a drastically different thing than "self-defense" to many experts. Just look the term 'bear arms' up in the Oxford English Dictionary, it is a term with a strong military service implication (unlike 'self-defense').  See for instance here for an reliable article just today explaining the distinction.  I could point to many other reliable sources too, see for instance this list of books, or this passage, and many more I could provide.  I acknowledge that in modern popular culture, and to some experts, the term 'bear arms' is synonymous with 'self defense', but that is far from the view shared by many notable historians. A third ambiguous synonym is that 'bear arms' means a right to hunting, which dates back to the Game Act, see the Joyce Lee Malcolm book, but that is another question.  Not to mention the heraldry meaning of 'bear arms'.  I would support a project to create a 'Bear arms' disambiguation page.   SaltyBoatr (talk) 19:21, 28 January 2008 (UTC)
 * See also this study by the historian John Kenneth Rowland which analyzes 300 usages of the term 'bear arms' in the historical documents from 1618-1791 and found  the overwhelming preponderance of usage of 300 examples of the "bear arms" expression in public discourse in early America was in an unambiguous, explicitly military. I acknowledge that there may be a tiny fraction of 18th Century usage that are ambiguous or 'individual', and you see some POV legal scholars and at least one Judge (Sam Cummings) point this out.  But, among historians, the consensus is quite clear, 'bear arms' to the founding fathers, implied military.  Read the list of historians, all professors at major universities, giving support to the Heller brief: Jack N. Rakove, Saul Cornell, David T. Konig, William J. Novak, Lois G. Schwoerer, Fred Anderson, Carol Berkin, Paul Finkelman, R. Don Higginbotham, Stanley N. Katz, Pauline R. Maier, Peter S. Onuf, Robert E. Shalhope, John Shy and Alan Taylor.   Read the Declaration of Independence usage of 'bear arms', Captive on the high Seas to bear Arms, as conscripts (deck hands) on warships, certainly prohibited from touching a gun or gun powder by the British naval officers in charge, and most certainly not for self-defense.  Again, I acknowledge a need to disambiguate this, but to merge?  A strong no.  SaltyBoatr (talk) 21:26, 28 January 2008 (UTC)

SaltyBoatr, that's true, but then I'm confused: How should I expand this article? Clearly, a lot of stuff in Right to bear arms doesn't belong. John Locke specifically talked about right to self-defense, English Common law was the basis for both the right to self-defense and the right to bear arms. What should both articles contain, in your opinion?
 * Can you mention what you are reading to get the idea that English Common Law was this basis? Have you read the book by Joyce Lee Malcolm, it states otherwise.  The 'right' to bear arms came from the Glorious Revolution.  Prior to that it was a 'duty'.  SaltyBoatr (talk) 08:03, 29 January 2008 (UTC)

I was going to do a bold re-write, but it occurred to me that I'd just be redundantly re-stating all the stuff that's already in Right to bear arms. ☯ Zenwhat (talk) 01:47, 29 January 2008 (UTC)

Basically, there doesn't need to be a full merge between right of self-defense and right to bear arms, just 90%, since right of self-defense is the broader topic. Right to bear arms should focus specifically on gun rights, particularly with regard to America's Second amendment, while "right of self-defense," would discuss Classical Liberalism, English common law, etc.. ☯ Zenwhat (talk) 01:49, 29 January 2008 (UTC)

 * Can you point to your sourcing of this idea? I don't think that, from a scholarly perspective, that 'the right to bear arms' equates with 'gun rights'.  This is a modern political concept, and is only half the POV.  Very little sourcing from historians says this.  You need to look to legal scholars (and only the half that are advocating that POV), and political editorials (again, only those advocating that political POV) to find this idea.  SaltyBoatr (talk) 08:03, 29 January 2008 (UTC)

 * Right to bear arms does not apply strictly to gun rights. There are all sorts of weapons to which it applies. That is the reason that in many states, the terminology of CCW (Carrying Concealed Weapon) is used, instead of Concealed Handgun License (which is also used in other states.)  An article on Right to bear arms needs to include the full range of weapons, not just guns. Yaf (talk) 13:33, 29 January 2008 (UTC)

 * It would be helpful if you could point to the WP:V sources forming the basis of your opinion, thanks. SaltyBoatr (talk) 14:56, 29 January 2008 (UTC)

 * Oppose merging right to bear arms into this article - the two are different concepts, which overlap to an extent, but refer to quite different things. (For example, one of the purposes of a right to bear arms - the original purpose, in the case of the U.S. 2nd Amendment - was to provide for the possibility that a people's militia could overthrow a tyrannical government, which has nothing to do with self-defence at all.) On the other hand, any material in that article which is clearly about the right to self-defence rather than the right to bear arms (e.g. it doesn't mention arms or weapons anywhere in it) can safely be moved to this article.

 * As for the other two articles, I'm more neutral - they could be merged here, but I feel they have enough content to stand on their own as well. If they are to be merged, you might want to think about merging Castle Doctrine as well - to my (limited) understanding, it seems to be describing exactly the same thing as the Make My Day Law, or certainly something very similar. Terraxos (talk) 04:14, 1 February 2008 (UTC)

 * Oppose on right to bear arms, support on the other ones. Make My Day State and Make My Day Law definitely should be one article; since this page is about the theory and legality of self-defense, they should land here until they grown enough to deserve their own spot (if ever).  Right to bear arms is distinct from the right of self-defense, and is broader than firearms law- there are sources in the right to bear arms article relating to this distinction.  There's also a lot to be discussed under right to bear arms (such as individual vs. collective right to own or carry weapons) that relates to the organization of an army or militia, and doesn't deal with the conventional legal definition of self-defense.  --Clay Collier (talk) 22:02, 29 February 2008 (UTC)

 * Strong Oppose. A topic such as "Right to bear arms" will draw intense debate and vandalism, with much of it merely repetitive for thousands of revisions. Separate articles for subtopics are typically justified for numerous other subjects, so combining a hot topic into another article is just double trouble. To simplify reverts, talk-up "Right to bear arms" as a simple overview article, then link to an abstract spinoff to describe real details, such as "Legal implications of right to bear arms".  Attempting to hide a hot topic in a larger topic will simply expose the larger topic to more hidden hacking. Instead, hide a hot topic under a related obtuse title but only about that single topic, leaving the original title ("Theory of Evolution") as a short overview article easily reverted for all the hacking it will continue to suffer. It will be amazing to see the limited hacking of "Legal implications..." compared to rampant hacking under the main title. When Wikipedia evolves into purging billions of minor revisions (which have grown exponentially), then many thousands of old "Right to bear arms" revisions can be purged because who cares about 10,000 continual edits to a short overview. That is a strategy for easily removing millions of minor revisions to controversial topics, long-term. Please consider future years of Wiki storage, trying to find major revisions, and shortening the Tower of Babel to allow faster wikiservers. -Wikid77 (talk) 10:39, 28 March 2008 (UTC)

Oppose in part, agree in part. The "Make my day law' & "Make my day state" articles could be absorbed into the broader "right of self defense" article, but due to the contention involved with weapons possession & use issues the mis-appropriately named "right to bear arms" page should be left on its own. Mikegtr71 06:04, 7 April 2008 (UTC)

 * Oppose the merging of the Right to Bear Arms. Yes, the right is in fact in place for self protection, but it is it's own right of the people, and shouldn't be confused with "the right to defend yourself".  I think there should be a Level 2/3 headline about the right to bear arms in this  article, but not to completely merge the two.  For example: The Traumahawk is medically operated by Palm Beach County Fire-Rescue.  The Traumahawk in fact has it's own article, because there is more information about it that doesn't need to be stated in one of the fire department it works for.  --  Aaron M. Lang (talk) 14:21, 9 April 2008 (UTC)

 * Oppose the merging of "Make My Day Law". The same logic applies for this.  There is more information on the law that doesn't need to be stated in an article on self defence.  Here, this is the right to protect your property (for the most part).  But, because it mentions protecting yourself and your family, etc., I think there should be a Level 2/3 headline on the subject.  --  Aaron M. Lang (talk) 14:21, 9 April 2008 (UTC)

 * Strong Oppose. These articles deserve to be separate. Right of self-defense is worldwide, but the other two are more related to the US. Heroeswithmetaphors (talk) 06:51, 10 April 2008 (UTC)

 * Strong oppose: these are two very different things. 163.1.146.198 (talk) 17:06, 22 April 2009 (UTC)

Since there have been no additions to this discussion for quite some time and it appears that the consensus was strongly against merging these articles, I am closing this discussion and removing the proposed merger tag from the mainspace page. -- JPMcGrath (talk) 09:01, 24 February 2010 (UTC)

Retrofit topic-year headers
28-March-2008: I have grouped older topics above using headers "Topics from 2004" (etc.) to emphasize age of topics. Older topics might still apply, but using the tactic of yearly headers to note the age helps avoid rehashing old news, without archiving any ongoing issues. Also, new topics are more likely to be added to the bottom, not top. -Wikid77 (talk) 11:03, 28 March 2008 (UTC)
 * The first level super section headings are not used in WP or talk pages. The date-time stamps give the years. Editors can use search functions to find topics by name, rather than by year. – S. Rich (talk) 05:30, 18 August 2014 (UTC)

Legal Status of Self-Defense
"In all but one U.S. jurisdiction, using deadly force against a robber or burglar who is attempting to escape with property is likewise not justifiable (Texas is the only exception and holds the defendant to a high burden of proof that the action was the only means available to recover the property without a serious risk of death or serious injury)."

I do not believe this is strictly correct. For example, New Jersey clearly provides for the use of force, and even deadly force, in defense of personal property. To be sure, there are limitations, but the fact remains that deadly force is a legal option. See, New Jersey Statues 2C:3-4, 2C:3-6, 2C:3-9, available from the New Jersey Legislature site, http://www.njleg.state.nj.us/ Ampermc (talk) 21:58, 2 July 2008 (UTC)

OK, further research shows that the use of deadly force in protection of property is only justifiable under NJ law if the use of deadly force is also justified under some other provision.Ampermc (talk) 22:39, 2 July 2008 (UTC)

Self-Defense Involving Police - Same Rules or An Exception to the Right of Self Defense?
Here's an interesting topic that I haven't seen covered very much and not in this article. Is there an exception to right of self-defense where police are involved? That is to say, if a person uses deadly force against a civilian who wields a sidearm against them, that is considered to fall under the right of self-defense. Does the same right apply if a person uses deadly force against a police officer who wields a sidearm against them? From this article and the sources I have seen, no distinction is made, but I have never heard of a successful claim of self-defense in this situation. Can something on this be added to the article? If such an exception or special case does exist it should be noted. 216.36.188.184 (talk) 02:39, 9 August 2008 (UTC)

Situation in Germany
There doesn't seem to be an article about this, but the situation in Germany is very different. Unknown to many, there is little to no comparison being done between the crime committed and the action taken as a self defense. You have to take the least aggressive defense if you have multiple options. But note this: For example you may shoot thieves of your wallet who are running away, if that's currently the only way to stop them. The general theme is: "Justice never needs to yield to Injustice" and "in doubt for the defender". German law influenced a lot of other laws so I wonder if there is more countries like this. Maybe someone with a background in law can do some research. The respective laws are StGB 32 and StGB 33 to give a starting point. --87.162.222.77 (talk) —Preceding undated comment was added at 15:23, 6 November 2008 (UTC).
 * you have the right to stand your ground, and flight never counts as a viable defense
 * if you have a defense that helps for sure and a softer one that's doubtful, you may always use the sure one
 * the only time when you have to restrict yourself is for bagatelles
 * the self defense extends to all crimes committed against you or others (but not against the public)
 * even deadly force is permitted for anything that's not completely negligible

Unref tag
I have placed this tag on this article because it has absolutly no intext refs.--SasiSasi (talk) 21:21, 12 September 2008 (UTC)

Self-defence in international law
I found the international law stub imminent threat which I added to include the context of the term, namely self-defence in international law. Because of this I was more or less at a loss what to do: should this topic be brought under the banner of right of self-defense or should a new topic be created? Marxmorley (talk) 13:23, 2 January 2010 (UTC)

True story about self-defense (Bullying victim attacked his bully)
Hi. I want to share a brief story.

In 4th grade, there was some terrible bullying. This guy kept trying to cause his victim much harm. He once stole a tuque from him, and, as a result, he got chased, and the victim shoved him to the ground, and forced him to give the tuque back.

Then, there was a much more serious episode. This time, he grabbed the victim's hair, and attempted to get a spark on his lighter, so he could set the victim's hair on fire. It never happened, but, I think it was attempted murder.

Anyways, those are just a few examples. One day, the victim got tired of this guy's bullying, and turned to violence. Now, this is important to know, that the bully was at least twice his victim's size. Guess who got easily dominated? The bully. The victim was so enraged, he had no control of his emotions, whatsoever. Sure, the victim got into most trouble with the school faculty, but, not with his parents.

Everything peaceful was tried (Except for calling the Police - the victim didn't want it to go that far.), and it didn't work, so, violence was an option. That's what the victim did, and, well, he never got bullied at that school, again.

Quick question about this. Was it 100% legal? Or, could the victim have been charged? If so, for what, and why? Thanks, for reading. --208.96.121.65 (talk) 16:18, 28 February 2011 (UTC)

 * They were in fourth grade. Fourth graders aren't usually "charged" with anything, especially over a school fight.65.0.171.189 (talk) 15:10, 20 June 2011 (UTC)

Remove junk?
"Most courts have ruled that such a defense cannot be used to protect friends or family members who have engaged in an illegal fight. Likewise, one cannot use this to aid a criminal."

This looks like it should be removed from the article.

I am at a loss to understand what exactly is meant by "illegal fight" and I doubt many can do better. Without a reference to clarify meaning or reason I believe that the statement too ambiguous and vague to be of use to the reader.

The second statement is too general to be true. "Criminal" [n] has a very broad definition. It might be better written as "to assist in a criminal act" but even that would be pointless as (knowingly) assisting in a criminal act is, assuming you pick a reasonable definition, often illegal irrespective of how. It's redundant in the same way that it would be redundant to state that murdering someone with an axe is illegal. — Preceding unsigned comment added by 82.12.161.116  (talk • contribs) 04:19, 13 October 2011 (UTC)

 * These are poorly worded, but I think the intent here is that you can't justify e.g. defending your brother who has just mugged somebody, but lost the upper hand. Some jurisdictions also regulate street fighting, boxing, etc., so they could define 'illegal fights'. 70.20.62.124 (talk) 06:25, 4 December 2011 (UTC)
 * yeah, that's probably possible. still better have references when it comes to law... I would completely find it normal if it was the other way around, so I can't be sure. 173.180.202.22 (talk) 21:42, 12 March 2012 (UTC)

Florida's self-defence law?
I was hoping this article which I found by typing "self defence law" into Wikipedia's search box would tell me more about this law which is apparently used as a defence in Shooting of Trayvon Martin. Unfortuantely I cannot find anything? Ottawahitech (talk) 18:20, 21 March 2012 (UTC)

Article scope
I agree with comments that, given the title, the article is far too US-centric. There is another article - Self-defence in international law - but that is too brief to reflect the current international controversy. Some of the classic international examples of claimed self-defence and US involvement on the international arena are perhaps inadequately addressed or referenced in both articles, such as:
 * the US intervention in Iraq in 2003
 * the Cuban missile crisis
 * the Israeli invasions of Syria and Egypt in April and June 1967 respectively
 * The invasion of Nicaragua
 * the Osirak reactor destruction
 * the South African invasion of Angola

Further, the concept of "Anticipatory self-defence" is not addressed, while existing articles such as "Preemptive war", "Self-defence in English law" and the "Bush doctrine" are not referenced. The title seems to me to be very "high-level" requiring referencing to sub-categories such as those mentioned. The current article could perhaps be renamed to reflect its focus.

Since I am very new here, I ask for some education as to how these issues are customarily addressed. Enquiringeric (talk) 11:36, 12 April 2013 (UTC)

Quality
This is a complete mishmosh. It reads like a term paper begun eight hours before it is due. Could somebody who is a good and careful writer start over? Perhaps start by deciding on the points they want to make? 50.0.36.122 (talk) 02:16, 28 July 2014 (UTC)

Violence
WTF is the idea behind saying that the use of force involves violence is a POV statement? Whadya think the "right of self-defense" means - the right to challenge your attacker to a game of chess? To file a complaint at the police station? When people talk about "reasonable force" or "deadly force" they're talking about violent actions. Don't pussyfoot around that basic fact. Felsic (talk) 16:18, 6 February 2015 (UTC)
 * If you went to hit me and I raised my arm in self-defense, I am attempting to block your action or use of force, but I am not doing anything "violent" as you contend. Your reasoning is flawed and inaccurate. --Scalhotrod (Talk) ☮ღ☺ 16:38, 6 February 2015 (UTC)
 * Are you seriously arguing that that's what this article is about? The right to raise a blocking arm or shut an open door? Can you tell me what POV is being pushed by saying that the use of force to defend oneself involves violence? Lemme see the sources you're using for this idea of non-violent force being used for self-defense. Felsic (talk) 16:53, 6 February 2015 (UTC)
 * So I guess the charge of "POV pushing" was just an unsupportable smear on other editors. Felsic (talk) 9:12 am, Today (UTC−8)

 * Actually I'd like to see your sources claiming that all "uses of force" involve violence. I'm basing my viewpoint on what I learned in a California Department of Justice certified police academy. The continuum or escalation of force is discussed pretty extensively in the academy. For example, that continuum starts with an officer just being on scene wearing their uniform or having a badge displayed and then escalates to conversation, orders given, and even the volume of their voice. Are you going to claim that these levels of "force" are all violent? --Scalhotrod (Talk) ☮ღ☺ 18:53, 10 February 2015 (UTC)
 * And I'd like to see your justification for saying that this article is about "the right for persons acting on their own behalf to engage in a level of violence, called reasonable force or defensive force," is "POV". What "POV" is being pushed by the editor who wrote that?
 * Nobody has ever had to face a judge and jury to defend themselves for displaying their badge. That's not what this article is about. This article isn't about walking away, or closing a door. By any normal interpretation, "self-defense" refers to the use of violent force to repel violent force. Anything less than violent force isn't an issue. Felsic (talk) 19:53, 10 February 2015 (UTC)

 * So which of any of the sources in this article validates your claim that self defense always involves violence? If you have never had training in the "use of force" I can understand why you don't understand fundamental principles of it. If that is the case, why are you editing this article? --Scalhotrod (Talk) ☮ღ☺ 20:10, 10 February 2015 (UTC)
 * You can't justify your accusation of "POV"? The same POV that's been in the intro since it was written in 2003? If you can't explain that attack you oughta withdraw it.
 * This article isn't about "use of force" or other LEO jargon. It's about the "Right of self-defense", not the "right to show your badge". You're last sentence sounds like you're trying to get me to stop editing this article. Felsic (talk) 20:26, 10 February 2015 (UTC)

 * I agree with Felsic. this is an article about the "right to self-defense." Any attempt to say otherwise appears to be a WP:PISSINGCONTEST. The legal system never had a single case where someone had to claim "self-defense" for using, uh, "non-violent force." I don't think that even exists. It's not a thing. It makes zero sense.Shark310 20:51, 10 February 2015 (UTC)

 * First off, there was no attack as you claim, so there is nothing explain. On the other hand, you seem to misunderstand the policy behind WP:LEAD. If terminology or a viewpoint is not substantially sourced and mentioned in the body of an article, then it does not belong in the Lead per WP:LEAD or WP:UNDUE. The length of time that it has been there is irrelevant. Referring to it as "violence" when other neutral terms convey the principal just as easily, makes it biased IMO and thus the mention in my Edit summary about "POV". I suppose I could have just as easily cited UNDUE. --Scalhotrod (Talk) ☮ღ☺ 20:57, 10 February 2015 (UTC)
 * What non-neutral "POV" is it that says the "force" being discussed in this article is "violent force"? How does the use of the word "violent" bias this article? You've made that claim as the justification for your accusation, so please explain it. It sounds like trying to replace clear language with a vague euphemism "certain actions". Felsic (talk) 21:04, 10 February 2015 (UTC)

 * Given the collective edits that and  have made, I think the Lead IMO is an accurate and neutral summary of the article, so this discussion has become moot. Thank you for your contributions. --Scalhotrod (Talk) ☮ღ☺ 17:20, 11 February 2015 (UTC)
 * Next time don't make baseless accusations of bias and POV. Felsic (talk) 15:59, 12 February 2015 (UTC)
 * It would help if you assumed good faith and did not take things so personally. My original edit summary, which apparently triggered your comments, was not directly at your or anyone else, but I will keep your comments in mind. --Scalhotrod (Talk) ☮ღ☺ 19:38, 12 February 2015 (UTC)
 * It'd be easier to assume good faith if you'd demonstrate it by explaining your accusations of POV and bias instead of just tossing them out as facts while you revert. Felsic (talk) 17:27, 19 February 2015 (UTC)
 * But that ain't gonna happen. Felsic (talk) 16:57, 20 February 2015 (UTC)

Poopy writing in section Legal Defense for Self-Defense Claim
Here's a 16 Dec. 2018 copy of Legal Defense for Self-Defense Claim:

Legal Defense for Self-Defense Claim

When trying to claim a self-defense case it will all depend on the threat. Was it a verbal threat to where the person felt threatened. To where he or she felt like they needed to defend themselves. It will also depend on if the threat was imminent or not.[5] Was the threat about to happen, was the person's life really in danger. Did he or she provoke the person for the attack to happen. When the person attacked the person, did his or hers self-defense match the threat. Was it an overkill to where the person ended up dead. To where you didn't need to put that much force towards a person. Was it a 'castle doctrine' defense.[6] Did they intentionally break in your home and try to harm you or your family to where he or she had to defend themselves or others using deadly force. To claim self-defense one of these things must have happened.

The grammar and writing style are plainly poopy. I'd fix it, but I lack the time just now. Could someone else, please? Cramyourspam (talk) 02:26, 17 December 2018 (UTC)

 * I, too, found this section wanting, but before I attempt any revision, I wish to make its faults explicit. Here is an initial portion:

 * Claiming a self-defense case will greatly depend on the threat.

 * Nobody claims a "self-defense case"; presumably the defendant is the person who was charged and arrested rather than the person he considers to have been the assailant, so he presents, through his attorney, a claim to self-defense. Moreover, it is not the claim to self-defense that depends upon anything, but rather the likelihood of a favorable verdict.

 * Next:

 * This includes whether it was a verbal threat that made the person feel threatened, to the extent that he or she felt the need to defend themselves. It will also depend on if the threat was imminent or not.

 * The antecedent of "this" is unclear, "this includes whether" is grammatically inept, for the verb to include cannot have as object a subordinate clause, and "made the person feel threatened, to the extent that" is wordy.

 * In any event the author wishes to emphasize the possibility that a favorable verdict will be returned when the inciting act is one that in ordinary circumstances no reasonable person would interpret as requiring the use of force to escape or prevent harm. Since such a case is unusual, it should not be discussed first.  The first observations in answer to the question of the likelihood of a favorable verdict should involve the paradigmatic or prototypical solid case.

 * Next:

 * Some questions to ask are whether the threat was about to happen and person's life really was in danger. Also, did he or she provoke the person for the attack to happen. When the person attacked the person, did his or her self-defense match the threat, or was it an overkill to where the person ended up dead when they didn't need to put that much force towards a person. Was it a 'castle doctrine' defense. Did they intentionally break in the person's home and try to harm the person or their family to where he or she had to defend themselves or others using deadly force. To claim self-defense one of these things must have happened.

 * On the whole, several solecisms make me suspect that English is not the native tongue of this paragraph's author. The most salient problem is the use of "the person" to denote every agent involved, which creates problems in the sentence about the intentionally break-in, since in the foregoing sentences the principal agent is the defendant, but in this one suddenly "they," that is, the assailant, is suddenly the principal agent.   Finally, since the specifications are questions, and not all of them specify conditions for a favorable verdict, the last statement is simply false.

 * The revised paragraph might run:

 * The likelihood that a jury or judge will sustain a claim to self-defense always depends upon evidence that any reasonable person would have interpreted the circumstances and the inciting act as such as to have left the defendant no other choice to escape harm than the degree of force that he in fact used.

 * The principal conditions for a favorable verdict are these: (i) the alleged assailant performed some act, or both the alleged assailant and the defendant were engaged in some exchange, in which it is ordinarily the case the one or both are animated by heated passions and the situation is volatile; (ii) the alleged assailant then performed some crucial act that a reasonable person would interpret as one that either threatens to push or does push the situation to such a degree of volatility that no participant or witness can understand it really to be in either participant's control; (iii) the alleged assailant performs what any reasonable person would interpret as the inciting act, i.e., one that the reasonable person would interpret as a prelude to a harmful or an attempt at a harmful act; (iv) the circumstances must be such that any reasonable person would understand that the defendant had no other means to escape or prevent harm than to use violent force; (v) the defendant's use of force was necessary and sufficient to prevent the harm or to incapacitate the alleged assailant and no more; (vi) the alleged assailant had entered the defendant's home or property with clear intent to put either the defendant's property or person or the persons of members of his household or property under his control or to do them harm, so that the defendant's act was not defensive but preemptive in general, and in its force necessary and sufficient to prevent harm or to incapacitate the alleged assailant and no more—the castle doctrine.

 * In cases in which the alleged assailant's inciting act was a verbal threat, the defendant must show that a reasonable person would have interpreted it as the prelude to an imminent physical assault to escape or to prevent which the defendant had no choice but to use physical force necessary and sufficient to prevent or incapacitate and no more.

 * If this seems reasonable, I will revise accordingly. The paragraph might be too long, but it can be broken into bullet points. Wordwright (talk) 21:16, 11 March 2020 (UTC)

Proposal to merge son assault demesne into this article
User:Someone who's wrong on the internet proposed merging son assault demesne into this article, but neglected to begin a discussion at either article. Since the "discuss" link leads here, I'm starting it here. Son assault demesne is described as a plea entered to justify (i.e., as a defense to the charge of) an act of assault and battery. I think that it makes good sense to cover it together with other self-defense related arguments. However, this article is in need of substantial cleanup, while son assault demesne is in relatively good order, if a bit brief. I would recommend cleaning it up before merging son assault demesne here, because otherwise this article will be even more of a mess, and harder for readers to navigate. If someone is willing to undertake that task, then I would support a merger after this article is put into a better state.

I also suggest that son assault demesne could stand to be reworded, both to make it a little clearer, and so that it's not entirely or almost entirely quoted from a nineteenth-century legal dictionary. Some nineteenth-century prose is excellent, but that doesn't strike me as the case with son assault demesne, and I dislike using attribution templates alluding to the incorporation of language from public domain sources, because then if anybody edits the text, it becomes unclear what is quoted and what is not. Better to reword long passages for clarity, even if they're still cited to the same source—which is fine—and mark exact quotations using quotation marks or block paragraphs within non-quoted text. P Aculeius (talk) 15:05, 18 March 2023 (UTC)
 * I've done this simply; feel free to improve at the target; not that merge templates assist with maintaining attribution. ✅ Klbrain (talk) 11:13, 26 November 2023 (UTC)

Moving name of page to "Right of self-defense (United States)"
I propose the name of the page should be moved to "Right of self-defense (United-States)" due to the US-centric information found on this page. Once the name is moved, it would be beneficial to add self-defense on a global scale with United States involvement. @Enquiringeric mentioned a few topics that could be added to this section. Greenthumb7 (talk) 17:24, 25 January 2024 (UTC)

Removal

 * . One might argue this example belongs to page Self-defence in international law (rather than to this page), because it is about the right of countries, rather than individuals or the general concept. But then it needs to be framed as an example of usage of international law. But I would argue this is an extremely poor (too complicated) example to clarify the concept. This is a controversy that needs a significant space to explain. My very best wishes (talk) 15:53, 11 March 2024 (UTC)

title: Talk:Right of self-defense


text:
Talk:Arc length

Error in proof
In the second section the mean value theorem is used on a vector-valued function, but the theorem only holds for real-valued functions. For example the proof doesn't hold for the curve $$f(t)=(\cos(t),\sin(t),t)$$ for $$t\in [0,2\pi]$$, since $$f'(t)=(-\sin(t),\cos(t),1)$$.

An alternative proof of the arc length formula could rely on Fatou's lemma. If $$\text{len}(f)$$ is at first defined using the integral formula one can show that $$\text{len}(f)=\text{sup}_{\text{partitions of [a,b]}}\sum_i |f(t_{i+1})-f(t_i)|$$ by (i) showing by direct inequality that a straight line is the shortest path between two points (giving $$\geq$$) (ii) $$\text{len}$$ is lower semi-continuous according to pointwise convergence of the derivatives of curves (using Fatou's lemma) (iii) every smooth path ($$C^1$$) has a succession of piecewise linear curves with vertices on the curve whose derivatives converge pointwise to the derivative of the path (giving $$\leq$$).

One could also prove the result for when $$n=2$$ using only the mean value theorem and the implicit function theorem. — Preceding unsigned comment added by 87.6.200.188 (talk) 17:07, 26 April 2020 (UTC)

old comments
I think it should be redirected to curve

Tosha 01:25, 15 Mar 2004 (UTC)

 * I completely disagree with you, Tosha. I think this deserves a page on its own.

 * This means that in discussion of the geometry of the curves, any links to arc length now jump directly to the curves article. This is a disservice to readers navigating these articles who expect to go directly to a discussion of the concept of arc length, rather than to to the article on curves. -- Decumanus 19:39, 15 Mar 2004 (UTC)

 * I agree; this page can stand on its own. Michael Hardy 21:34, 15 Mar 2004 (UTC)

 * Ok, I think this way it is harder to keep it uptodate, but do as you wish.Tosha 23:56, 15 Mar 2004 (UTC)

This article is incomplete. It needs cleanup. I wikified the maths, but some of the formulas didn't seem to make sense the way they were written, so they should be checked.

The article is also in sore need of some images.

I reordered the article and fixed some of the math. It still needs more work though -Jacob 01:38, 14 June 2005 (UTC)
 * I've been fixated on the text bit - now that I look closely, that explanation of the Fermat math doesn't look right. It keeps sprouting unexplained new variables. Tearlach 19:37, 16 July 2005 (UTC)

 * I only fixed the LaTex formating of the math -not the content- now that I look criticaly, I see what you mean. It looks like the original author of the page just rewrote it from the pdf he cites. Reading the file explains what he was getting at. We I get some more time, I'll make a plot so one can follow along. We should add the final part too (from the pdf) where the formula shows that Fermat really did find the integral and his formula, he just didn't understand the implications. I'd like another source for verification that this is how it historicaly happened.
 * As far as I understand it, both van Heuraet and Fermat derived that if you have a function f(x), then the arc length is given by the area under a new function g(x) = sqrt(1 + f'(x)^2). So they had the function to be integrated, but not the integral calculus to apply to it. Tearlach 11:49, 17 July 2005 (UTC)

A bit added about the problems. As it stood, it was overoptimistic about the benefits of applying calculus. PS Semicubical parabola is y^3 = a*x^2. Tearlach 23:24, 15 July 2005 (UTC)

More bibliographic detail: Heuraet at MacTutor, Rida T Farouki reference here (PostScript) and here (text). Tearlach 07:26, 16 July 2005 (UTC)

And this Wallis biography from WW Rouse Ball describes van Heuraet's method for curve rectification. Tearlach 13:07, 16 July 2005 (UTC)

I added a graph for Fermat's method. I had different colors for the line originaly, but somehow, gnuplot stoped changing them as the code evolved. See for the code and please help me fix it. --Jacob 18:09, 22 July 2005 (UTC)

The location "Arc length" is arrived at from "Curve length". No idea how history brought us to this situation. Clearly, this article should be "Curve length", and "Arc length" should redirect to "Arc_(geometry)". 68.84.233.37 (talk) 10:50, 30 June 2013 (UTC)

Article title
According to the article Arc, an arc is a continuous portion of a circle; part of a circle's circumference (also called a circle segment). The present article is about curves. It uses the undefined term "irregular arc", but in fact even in the present text the use of the term "curve" dominates the use of the term "arc". My conclusion is that the title ought to be: Length of a curve. Lambiam Talk 03:09, 9 April 2006 (UTC)

 * Actually, I prefer arc length, as that is what the concept is usually called in calculus books and more advanced books on differential geometry. The other names should just redirect to arc length.  I also suspect that when writing an article, most mathematicians would use arc length, so this avoids unnecessary redirects.

 * There are terminology issues, as you've noticed. "Arc" actually is used to refer to more than what is currently in arc.  In geometry/topology areas, it actually means a continuous map of the unit interval, and often in differential geometry, "arc" refers to "rectifiable arc".   This usage of "arc" is actually fairly old, and that is the "arc" that is referred to by "arc length"; it may be tied to the historical "irregular arc" mentioned in the article.  I think, though, that more people prefer "path" or "curve" over "arc" nowadays in topology.

 * In answer to your objection, while it may be strange that "curve" dominates "arc" in the article, it's just an artifact of history and usage that "arc length" has become the standard term rather than "curve length", although of course, people would probably understand what you mean by the latter in the appropriate context.  --C S (Talk) 03:58, 9 April 2006 (UTC)

 * I did a bit of research on other treatments. Mathworld, under "arc length", defines "Arc length is defined as the length along a curve" and proceeds to give a treatment that will blow away all non-mathematicians; it appears to presuppose differentiability. PlanetMath, under "arc length", defines: "Arclength is the length of a section of a differentiable curve" (italics added, L.), and the treatment given corresponds more or less to that of our Length of an arc. We also have Curve, which is somewhat unreadable and probably quite incomprehensible to the mathematically untrained, but in essence what I believe the Length article should cover: length as a kind of limit, with differentiable curves in Euclidean 2-space as a special case. Alternatively, we should make clear that this article covers only an important but nevertheless special case and insert a link to the more general, unfortunately unreadable, treatment. Lambiam Talk 06:19, 9 April 2006 (UTC)

I prefer arc length, I'd like to see this article moved to there. -lethe talk [ +] 17:43, 9 April 2006 (UTC)

 * I also prefer arc length. The more general stuff at curve I think is also called arc length, but in the case of metric spaces, so it should be treated here. --MarSch 10:24, 11 April 2006 (UTC)
 * I have moved the article. This required deleting and merging old history, since there was once an article arc length, which has a history, and was improperly made into a redirect by Tosha in 2004, in violation of the GFDL. -lethe talk [ +] 19:42, 11 April 2006 (UTC)

Length of Circular Arc Segments
As this article is named Arc Length, I believe it should at its outset completely and clearly address the generally understood notion of Arc pertaining to a segment of a circle before it addresses the arc lengths of curves. The current definition of a circular arc, while technically correct is woefully inadequate to general users and difficult to find on the page. In order to make Wikipedia useful to the general populace, think like and write to non-mathematicians first, then delve into the higher notions of the concept.

 * I completely agree with this. This is an endemic issue in most of the math sections on Wikipedia. Usually little to no regard is given to those who are seeking to understand the basics of the concepts and the articles dive headlong into the higher math without giving adequate explanations of what the formulas mean. Most people who are looking for information on Wikipedia don't "speak math" like we do and often skip right over the formulas. I know that the formulas are the most concise definition, but only for those that already understand the concepts or know how to speak mathematics. In the effort to be concise and complete the usefulness of the encyclopedic information often becomes nullified. It is easy to forget who our customers are, who uses the information and what is its purpose? Start with the most basic commonly held definitions give them a solid foundation and build on them. Dissymmetry (talk) 14:46, 7 June 2012 (UTC)

standard definition
The standard definition of arc length---the sup of polygonal path lengths---is not even mentioned here. I'll be back..... Michael Hardy 22:51, 7 May 2006 (UTC)

 * That definition applies to all curves in a metric space, not just rectifiable arc segments (differentiable curves?) in Euclidean space, in which case one might wonder why the article is not called "Curve length" or something like that. See also the above discussion on the article title. If someone feels like improving the present article, then note that it never defines what an "irregular arc segment" is, does not give any definition of arc length but only ways to determine it, and further confuses functions with their graphs plotted as curves in space. I also find the account under "Ancient" rather dubious and doubt that it is true as stated.

 * If general curves are treated, it would be reasonable to give fractal curves as an example of curves of infinite length; see also How Long Is the Coast of Britain? Statistical Self-Similarity and Fractional Dimension. --Lambiam Talk 23:25, 7 May 2006 (UTC)

"Rectifiable" does not imply "differentiable". I thought "rectifiable" meant the total length is finite, regardless of differentiability, or at least the length between any two points on the curve is finite (as with a line). Michael Hardy 03:13, 9 May 2006 (UTC)

 * The parenthetical question was a guess at a possibly intended meaning of "arc segment", given PlanetMath's definition of "arc length" as "the length of a section of a differentiable curve". --Lambiam Talk 08:44, 9 May 2006 (UTC)

In regard to curves that have infinite length between two points on the curve, one could see also space-filling curve. Michael Hardy 21:35, 9 May 2006 (UTC)

 * Indeed, a special but well-known case of fractals having Hausdorff dimension equal to 2.

Isn't there also a definition based on the limits of a cover of balls? --njh 11:51, 16 May 2006 (UTC)

 * Both Hausdorff dimension and Minkowski-Bouligand dimension say something like: I am what you get as a limit of a cover of balls. Both are written in a way that makes it hard to see how this relates to the more formal definitions given. How they can be "informally" the same but actually different is not immediately clear to me. --Lambiam Talk 13:12, 16 May 2006 (UTC)

 * They talk about computing the dimension of a structure. I recall there being a way to define arc length itself as a covering. --njh 02:19, 17 May 2006 (UTC)

Derivation
I would like to show the derivation of at least the fundamental parametric arc length formula, however since I'm new to this math format and it is a moderately long explination, I'm going to be working on it here and moving it into the article once it is complete and has been peer reviewed. Please let me know of any errors that you may see, I will move it into the main page in the near future. If anyone might be able to explain the conversion of this integral into the one used for ordinary functions (f(x)) it would be very useful.

In order to approximate the arc length of the curve, it is split into many linear segments. To make the value exact, and not an approximation, we will need infinitely many linear elements. This means that each element is infinately small. This fact manifests itself later on when we use an integral.

We start by looking at a representative linear segment (see image) and observe that its length (element of the arc length) will be the differential ds. We will call the horizontal element of this distance dx, and the vertical element dy.

Now, recall the distance formula which tells us that

 * $$ds = \sqrt{dx^2 + dy^2}$$.

Since the function is defined in time, we add up the segments (ds) across infintessimally small intervals of time (dt) yielding the integral:

 * $$\int_a^b \sqrt{\bigg(\frac{dx}{dt}\bigg)^2+\bigg(\frac{dy}{dt}\bigg)^2}\,dt$$

Which is the arc length from $$t=a$$ to $$t=b$$ of the parametric function f(t).

For example, the curve in this figure if defined by:

 * $$\begin{cases} y = t^5 \\ x = t^3 \end{cases}$$

Subsequently, the arc length integral fo values of t from −1 to 1 is:

 * $$\int_{-1}^1 \sqrt{(3t^2)^2 + (5t^4)^2}\,dt = \int_{-1}^1 \sqrt{9t^4 + 25t^8}\,dt$$

Using computational approximations, we can obtain a very accurate (but still approximate) arc length of 2.905.

48v 03:18, 12 July 2006 (UTC)

 * This has now been added to the article. 48v 21:30, 14 July 2006 (UTC)

---

A revision of the first image, swapping labels dx and dy is at http://en.wikipedia.org/wiki/File:Arc_length_approximation.svg. It also has the ds label moved. This article's preceding section says, "Consider an infinitesimal part of the curve ds (or consider this as a limit in which the change in s approaches ds)." which seems to allow either the portion of curve within the triangle or the straight line which approximates it to be labeled ds. I'm not sure which is more proper. Should the revised images have the ds label at the original location?

96.48.157.217 (talk) 13:59, 16 April 2013 (UTC)

Whbny (talk) 21:06, 4 February 2018 (UTC)whbny %%% The last derivation regarding arc length being independent of parametrization has a few serious problems. First, a continuously differentiable bijection does not need to be non-decreasing: for example, \phi(x)=-x. Second, the inverse of a continuously differentiable bijection need not be differentiable: consider the bijection \phi(x)=x^3, whose inverse bijection fails to be differentiable at x=0. In fact, the derivative of \phi^{-1}(x) becomes unbounded around x=0. These matters can be fixed (I can fix them but I need to get more accustomed to using this Talk page and format).

Notations used in formulae
The lowercase 'e' in italics is used for Euler's Number. The symbol used in this context should be 'ε' or 'є,' not e.
 * The Roc 1217 22:28, 4 April 2007 (UTC)

Derivation without parametric
I think the article is missing a good demonstration not involving the parametric form. This is my work on it, and I think it could be included in the article, though a more rigorous treatment is welcome.

We have a function f(x). It is continuous in the interval [a,b]. Now, let us divide this interval in equal parts, Δx. Starting from a, each successive increment in x, will also increment the f(x), and the arc lenght of that part will be given as:
 * $$ L_i = \sqrt{\Delta x^2 + [f(a+i\Delta x))-f(a+(i-1)\Delta x]^2}$$

Foe example, the first increment will result in an arc length of approximately:
 * $$L_1 = \sqrt{\Delta x^2 + [f(a+\Delta x))-f(a)]^2}$$

The total arc length will be:
 * $$L_T = \sum_{a}^{b} \sqrt{\Delta x^2 + [f(a+i\Delta x))-f(a+(i-1)\Delta x]^2}$$
 * $$L_T = \sum_{a}^{b} \sqrt{\Delta x^2\left(1 + \left[\frac{f(a+i\Delta x)-f(a+(i-1)\delta x]}{\Delta x}\right]^2\right)}$$
 * $$L_T = \sum_{a}^{b} \Delta x\sqrt{1 + \left[\frac{f(a+i\Delta x)-f(a+(i-1)\delta x]}{\Delta x}\right]^2}$$

Now, taking the limit as Δx becomes infinitesimal, and summing up all the parts, we get the expression:
 * $$L_T = \int_{a}^{b}\sqrt{1 + [f'(x)]^2}\, dx$$

Goldencako 00:41, 7 November 2007 (UTC)

First section, "General approach", needs work
This section reads as follows:

"A curve in, say, the plane can be approximated by connecting a finite number of points on the curve using line segments to create a polygonal path. Since it is straightforward to calculate the length of each linear segment using the theorem of Pythagoras, the total length of the approximation can be found by summing the lengths of each linear segment.

Using a larger number of segments (with each segment often of a smaller length) usually provides a better approximation to the curve, and the length of such an approximation will be greater than one using fewer segments.

For some curves it is the case that none of the lengths of the approximations exceeds a certain smallest number L. If such a number exists, then the curve is said to be rectifiable and the curve is defined to have arc length L."

The first paragraph should be removed entirely, since above all, how to calculate arclength for practical purposes is a separate issue from how arclength is defined -- the definition is more basic and should come first and be clearly labeled as such. (Even if it were appropriate to begin with a discussion of how to *calculate* arclength, this paragraph makes no statement that the cartesian coordinates of the segments' endpoints are known -- which makes the mention of "using the theorem of Pythagoras" irrelevant.)

The word "usually" in the second paragraph seems strange. To make sense, it needs to be stated what a "better approximation to the curve" means, if this phrase is to be used.

The third paragraph is false as stated. (E.g., the length of each polygonal approximation to a unit circle does not exceed 99, but 99 exceeds 2π, the arclength of this circle.)Daqu (talk) 09:08, 17 August 2008 (UTC)

 * In order to create this new section I separated out statements about the intuition behind calculating arc length, and provided a better definition (see the history for more details), so some of it is a re-write of stuff previously included. The previous version had intuitive statements about arc length being defined for R2, and I thought that keeping these ideas in the context of the plane was a good way of introducing the idea, since, perhaps, most people might find the idea of a curve in n-dimensional space a little intimidating.

 * I disagree that the definition is more basic than the intuitive version, for two reasons: (1) It's not more basic for non-mathematicians; (2) The definition is precisely that intuitive concept given symbolic form.

 * The language for this section is written informally: if you think it needs work, go ahead and make the changes. And if it's imprecise, go ahead and make those changes too. It's anybody's article.

 * Finally, the cartesian coordiates of the segments' endpoints is relevant only if one is working in Euclidean space; if X were a general metric space, I don't know what "cartesian coordinates" would mean. Xantharius (talk) 21:37, 17 August 2008 (UTC)

Slightly different way should be removed
This section is flagged with a cleanup, but it's not worth cleaning up. It's not substantially different from the main derivation, and full of grammatical and notational errors. I suggest it be removed. Bryanclair (talk) 20:29, 31 March 2009 (UTC)

 * I second this removal.—Tetracube (talk) 20:35, 31 March 2009 (UTC)

Time?
Would it not be better for the derivation to call t a parameter rather than saying "time"? 149.157.1.184 (talk) 16:53, 16 May 2009 (UTC)

Incorrect use of term "Straight Line"
Within section "Historical methods", subsection "Ancient", a 'straight line' is said to have a definite length. According to MathWorld a line (sometimes called a 'straight line') is "a straight one-dimensional figure having no thickness and extending infinitely in both directions".

In the context of this article, I believe the correct term should be 'line segment' which does have a definite length. Fhv1374 (talk) 08:02, 3 December 2009 (UTC)

petal
Hi. What means petal here ? petal of Lea-Fatou flower   ? --Adam majewski (talk) 18:08, 18 February 2013 (UTC)

incorrect edit by prodigy
The recent change to the formula for arclength is in error. Tkuvho (talk) 09:12, 29 December 2014 (UTC)

General approach section
I removed the following paragraph from this section:

Polygonal approximations are linearly dependent on the curve in a few select cases. One of these cases is when the curve is simply a point function as is its polygonal approximation. Another case where the polygonal approximation is linearly dependent on the curve is when the curve is linear. This would mean the approximation is also linear and the curve and its approximation overlap. Both of these two circumstances result in an eigenvalue equal to one. There are also a set of circumstances where the polygonal approximation is still linearly dependent but the eigenvalue is equal to zero. This case is a function with petals where all points for the polygonal approximation are at the origin.

"eigenvalue" and "linearly dependent" make no sense here. The entire paragraph is confusing, and the point it seems to be trying to make is inappropriate in a section that's trying to give a gentle introduction by explaining the basic idea. — Preceding unsigned comment added by 24.56.116.202 (talk) 17:00, 10 August 2015 (UTC)

Definition
Tosha, do you mean the curve should be defined as a piecewise differentiable mapping from an interval to $$\mathbb{R}^n?$$ This would certainly be a more useful definition for the vast majority of applications. Jrheller1 (talk) 23:38, 15 February 2016 (UTC)

Example of numerical integration
This information would be useful to anybody who writes a program that needs to calculate the arc length of a curve. It shows that the fact that there is usually no closed form solution for the arc length integral doesn't really matter because numerical integration (even very accurate numerical integration) is usually very efficient. Gauss-Kronrod rules and Gaussian quadrature rules are just the standard ways of doing numerical integration of a non-singular integrand. Jrheller1 (talk) 05:13, 5 March 2016 (UTC)
 * For theoretical purposes, especially on a general curve of a particular family (such as an arbitrary parabola for which you don't know its parameters), a closed-form solution is much preferable, even if given in terms of special functions like elliptic integrals. Anyone writing a program to compute arc length would probably use numerical integration even if the curve possessed a closed-form arc length formula, since even if it exists, it may be unsuitable for numerical purposes. More generally, the efficiency of numerical integration does no good for theoretical purposes for any definite integral in general. As someone focusing on pure math (at least for now), it only distracts me when I see a remark on numerical integration.--Jasper Deng (talk) 07:59, 5 March 2016 (UTC)
 * I find the practical information useful; the article needs not be just theoretical. fgnievinski (talk) 00:51, 12 March 2016 (UTC)
 * If someone wants to do numerical integration they can head over to the article on that. Why is adding numerical integration here any more useful than other situations not determinable in closed form, such as elliptic integrals and the error function?--Jasper Deng (talk) 21:19, 15 March 2016 (UTC)
 * Numerical integration is applied to many many different mathematical problems; it is impractical for all of them to be covered in a single article. As the OP explained, there are some nuances to this application, that are not obvious to the average reader. The error function can be consider a closed-form_expression. fgnievinski (talk) 00:59, 16 March 2016 (UTC)
 * But how are any of these nuances specific to the problem of arc length? The OP only mentions that these are generally applicable numerical integration methods, without discussion of how arc length integrands are any more suited to those methods than general integrands.--Jasper Deng (talk) 08:25, 16 March 2016 (UTC)
 * I'd support summarizing that sub-section as a single sentence, just mentioning that quadrature can be readily applied after finding a suitable parameterization; you're right in that currently not much is said about its details (which can be quite complicated); the lengthy numerical example is not particularly illuminating. fgnievinski (talk) 09:42, 16 March 2016 (UTC)
 * I think that would be satisfiable for me too. How about ?--Jasper Deng (talk) 07:19, 17 March 2016 (UTC)

The history of the page shows that there was an example of numerical integration for more than 9 years and nobody had a problem with it all that time. While removing several redundant and not very good derivations of the arc length integral, I removed this example temporarily back in February 2016. Then I replaced the previous example with a better example. In this new example, the integral has an easily computed transcendental value, so it is easier to analyze the error of Gauss or Gauss-Kronrod quadrature (or any other numerical integration method). How could anybody possibly have a problem with this improved example? Jrheller1 (talk) 04:16, 28 April 2016 (UTC)
 * That's not relevant. My issue is with including an example at all.--Jasper Deng (talk) 15:23, 28 April 2016 (UTC)

Smooth or C1
In the section Arc length it starts by saying
 * Let $$f:[a,b]\to\R^n$$ be a continuously differentiable function.

which means that the function is $$C^1$$, the remainder of the section seems to work for $$C^1$$ curves. The definition of a "smooth" function is that it is $$C^\infty$$. Should the section be renamed "Definition for a differentiable curve", or am I missing something?--Salix alba (talk): 05:10, 10 May 2016 (UTC)

 * "Once continuously differentiable" or $$C^1$$ is more precise than "smooth". Sometimes $$C^1$$ or $$C^2$$ curves or surfaces are referred to as "smooth", though. A $$C^1$$ or $$C^2$$ curve appears to be "smooth" (using the word smooth in a physical sense rather than strict mathematical sense).  Jrheller1 (talk) 02:00, 13 May 2016 (UTC)

 * I'm agnostic whether narrowing the discussion to $$C^1$$ is important (Wikipedia generally eschews highly technical arguments, and "smooth" is often understood by context), but I object to the use of $$|f'(t)|$$ rather than $$||f'(t)||$$. The function $$f(t)$$ and its derivative are vector valued, so the (Euclidean) norm rather than absolute value is needed in the arc length formula.Hardmath (talk) 06:12, 27 December 2017 (UTC)

 * Single vertical bars are often used for vector norm, for example in Rudin (one of the sources cited). Jrheller1 (talk) 16:40, 28 December 2017 (UTC)

Unnecessary verbiage
The words "where the supremum is taken over all possible partitions $$a=t_0<t_1<\dots <t_{N-1}<t_N=b$$ of $$[a,b]$$" are perfectly clear. But someone keeps inserting the unnecessary and distracting verbiage "please note $$N$$ is not a fixed number, i.e., the supemum is taken over all possible finite partitions of the interval $$[a,b]$$, where the curve $$f$$ is defined." Jrheller1 (talk) 04:52, 27 September 2016 (UTC)

 * The words "for any N" should suffice. 2601:200:C000:1A0:6923:FA76:F1E6:D668 (talk) 17:17, 16 July 2022 (UTC)

External links modified
Hello fellow Wikipedians,

I have just modified 1 one external link on Arc length. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
 * Added tag to http://www.pinkmonkey.com/studyguides/subjects/calc/chap8/c0808501.asp
 * Added archive https://web.archive.org/web/20110720095511/http://numericalmethods.eng.usf.edu/experiments/Length_of_curve_experiment.pdf to http://numericalmethods.eng.usf.edu/experiments/Length_of_curve_experiment.pdf

When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at ).

Cheers.— InternetArchiveBot  (Report bug) 03:26, 17 October 2016 (UTC)

 * Links checked and found to be ok, although this list might need some trimming. - DVdm (talk) 09:05, 17 October 2016 (UTC)

Norm, not absolute value
The section Formula for a smooth curve begins as follows:

"Let $$f\colon[a,b]\to\R^n$$ be an injective and continuously differentiable (i.e., the derivative is a continuous function) function. The length of the curve defined by $$f$$ can be defined as the limit of the sum of linear segment lengths for a regular partition of $$[a,b]$$ as the number of segments approaches infinity. This means $$L(f) = \lim_{N\to\infty}\sum_{i=1}^N \bigg|f(t_i) - f(t_{i-1})\bigg|$$ where $$t_i = a + i(b - a)/N = a + i\Delta t$$ with $$\Delta t = \frac{b-a}{N} = t_i - t_{i-1}$$ for $$i = 0, 1, \dotsc, N.$$ This definition is equivalent to the standard definition of arc length as an integral: $$L(f) = \lim_{N\to\infty}\sum_{i=1}^N \bigg|f(t_i) - f(t_{i-1})\bigg| = \lim_{N\to\infty}\sum_{i=1}^N \left|\frac{f(t_i) - f(t_{i-1})}{\Delta t}\right|\Delta t = \int_a^b \Big|f'(t)\Big|\ dt.$$"

But the appropriate notation for the distance between points in n-dimensional space is not the absolute value sign: | |, but instead it is the symbol for a norm: ⃦ ⃦. 2601:200:C000:1A0:6923:FA76:F1E6:D668 (talk) 17:15, 16 July 2022 (UTC)

 * Absolutely right! The argumentation is really misleading because it coincides with total variation. 149.139.33.244 (talk) 10:17, 21 July 2022 (UTC)

False statement
The section Formula for a smooth curve contains this statement:

"Let $$f\colon[a,b]\to\R^n$$ be an injective and continuously differentiable (i.e., the derivative is a continuous function) function. The length of the curve defined by $$f$$ can be defined as the limit of the sum of linear segment lengths for a regular partition of $$[a,b]$$ as the number of segments approaches infinity."

But "as the number of segments approaches infinity" is the wrong condition for the sum of the lengths of the approximating segments to approach the length of the curve.

(It is easy to come up with counterexamples where the number of segments approaches infinity, yet the sum of their lengths does not approach the length of the curve: Just keep the length of one segment of length > 0 fixed, while the others become more numerous and approach infinitely many.)

Instead, the correct condition is that the lengths of all the approximating segments of the inscribed polygon must approach zero.

Definition
"Arc length is the distance between two points along a section of a curve."

Isn't the distance between two points the length of the shortest segment that has those two points as endpoints? This is also what the Wikipedia page on distance says (if I interpreted it correctly). Wouldn't it be more appropriate to define arc length as the length of an arbitrary curve with two endpoints? Or if one doesn't wish to reuse the word length, the distance traveled along a curved path from a point to another point? I don't like this last definition because it kind of implies that something has traveled along the arc but anyways I don't mean to come up with a definition yet, I would just like to know if the definition on the Wikipedia page for arc length is correct. 131.114.35.40 (talk) 14:06, 26 October 2022 (UTC)

 * I agree, a better introductory definition would be: "The arc length is the length of a rectifiable curve." Stqckfish (talk) 17:37, 28 March 2024 (UTC)

Adding a definition section
In my opinion, the introduction of this article on the definition of a rectifiable curve is very unclear and it repeats itself, making it confusing. Therefore, I would propose adding a section entitled "Formal definitions." In this section, I would present the following definitions, and show that they are, indeed, equivalent:

1. For any sequence of partitions of [a,b] such that the lengths of the corresponding line segments of the curve converge to 0, the sequence of the sums of these lengths converges to the value L, the arc length.

2. The supremum of the set of all sums of lengths corresponding to a partition on [a,b] exists.

The first statement is the intuitive and mathematically rigorous definition of arc length. These definitions could be worded better and made more understandable with mathematical notation. I believe this would clear up confusion and make the whole article more accurate. Stqckfish (talk) 17:29, 28 March 2024 (UTC)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Talk:Arc length


text:
Joan Armatrading

Joan Anita Barbara Armatrading (, born 9 December 1950) is an English singer-songwriter and guitarist. Her first major commercial success came with her third and fourth albums, Joan Armatrading (1976) and Show Some Emotion (1977), and she continues to play live and record studio albums. A three-time Grammy Award nominee, Armatrading has also been nominated twice for BRIT Awards as Best Female Artist. She received an Ivor Novello Award for Outstanding Contemporary Song Collection in 1996.

Early life and education
Joan Anita Barbara Armatrading, the third of six children, was born in 1950 in the town of Basseterre in what was then the British colony of Saint Christopher and Nevis. Her father was a carpenter and her mother a housewife. When she was three years old, her parents moved with their two eldest boys to Birmingham in England, sending Joan to live with her grandmother on the Caribbean island of Antigua.

In early 1958, at the age of seven, she joined her parents in Brookfields, then a district of Birmingham. (The area, now mostly demolished, has been absorbed into the district of Hockley.) Her father had played in a band in his youth, later forbidding his children from touching his guitar. At about the age of 14 Armatrading began writing songs by setting her own limericks to music on a piano that her mother had purchased as "a piece of furniture". Armatrading then began teaching herself guitar after her mother had bought her one that was worth £3 from a pawn shop in exchange for two prams.

Armatrading left school at the age of 15 to help support her family. She lost her first job (as a typist and comptometer operator) after taking her guitar to work and playing it during tea-breaks.

Late 1960s and 1970s
Armatrading first performed in a concert at Birmingham University for her brother at the age of about 16. She only knew her own songs, but her brother asked her to perform something that would be familiar to the audience; she chose "The Sound of Silence". She then performed her own songs around the local area with a friend from school, and played bass- and rhythm-guitar at local clubs. In 1968 Armatrading joined a touring production of the stage musical Hair. There she met the lyricist Pam Nestor in 1970, and they worked together on Armatrading's debut album Whatever's for Us, released by Cube Records in 1972. Nestor wrote the lyrics to eleven of the 14 songs on the album, while Armatrading wrote the lyrics to three of them, performed all the vocals, wrote all the music and played an array of instruments on the album. Although Nestor was credited as co-lyricist, Cube regarded Armatrading as the more likely star material. These events produced a tension that broke up the partnership.

On 31 October 1972, Armatrading appeared on the BBC Radio 1 John Peel Show performing "Head of the Table", "Spend A Little Time", "Child Star" and "Whatever's For Us". She sang and played acoustic guitar and piano. In 1973 Cube released on the Fly label (catalogue: Bug 31) Armatrading's first single, "Lonely Lady" (with lyrics by Nestor), a song that had not been included on the album. It proved unsuccessful in the charts, and a period of inactivity for Armatrading followed while she extricated herself from her contract with Cube. The single was subsequently withdrawn by Cube and re-released as a promotional single in the US by Armatrading's new label A&M Records, the same year (as A&M1452). In January 1974 she appeared again on the John Peel Show. Performing "Some Sort of Love Song", "Lonely Lady" and "Freedom", she again sang and played acoustic guitar and piano, but was accompanied by supporting musicians Snowy White (guitar), Mike Tomich (bass) and Brian Glassock (drums).

In 1975, Armatrading was free to sign with A&M Records, and issued the album Back to the Night, which she promoted on tour with six-piece English jazz-pop group The Movies. Armatrading credited English singer Elkie Brooks on the sleeve notes as she had cooked for Armatrading and the band in the studio while they had been making the album, which was produced by Brooks' then husband Pete Gage. A major publicity relaunch in 1976 and the involvement of producer Glyn Johns propelled her next album, Joan Armatrading, into the Top 20 and spawned the Top-10 hit single "Love and Affection". The album mixed acoustic work with jazz-influenced material, and this style was retained for the 1977 follow-up Show Some Emotion, also produced by Glyn Johns, as was 1978's  To the Limit. These albums included songs which became staples of Armatrading's live shows, including "Willow", "Down to Zero", "Tall in the Saddle", and "Kissin' and a Huggin. Also at this time Armatrading wrote and performed "The Flight of the Wild Geese", which was used during the opening- and end-titles of the 1978 war film The Wild Geese. The song was included on the soundtrack album for the film, originally released by A&M Records, later released under licence as a Cinephile DVD. A live album entitled Steppin' Out was released in 1979.

Between 1972 and 1976, Armatrading made a total of eight appearances in session for the John Peel show, and the decade saw her become the first Black British female singer-songwriter to enjoy international success. On 14 May 1977, Armatrading appeared as the musical guest on NBC's Saturday Night Live. She performed "Love and Affection" and "Down to Zero".

1980s and 1990s
In 1980, Armatrading revised her playing style and released Me Myself I, a harder rock- and pop-oriented album produced by Richard Gottehrer, who had previously produced albums for Blondie. The album became Armatrading's highest ever charting album both in the UK and the US, while the title track became her second UK Top 40 hit single. In that year, she performed on Rockpalast night. The same pop style as on her previous album, now coupled with synthesisers, was also evident on the 1981 album Walk Under Ladders and 1983's The Key. All three of these albums were Top 10 successes in the UK, with The Key also producing the hit single "Drop the Pilot", Armatrading's third UK Top 40 hit single (UK #11). To capitalise on her success, A&M released the best of compilation album, Track Record, in 1983.

Armatrading performed in 1985 at a sold-out concert at the Red Rocks Amphitheater in Morrison, Colorado and another concert in Arizona with Cook da Books. That year she released her next album, Secret Secrets. The album was a top 20 hit but failed to yield any hit singles, cementing Armatrading's status as an "album artist". Taking over production responsibilities herself, she recorded the albums Sleight of Hand (1986), The Shouting Stage (1988) and Hearts and Flowers (1990) for A&M Records, which all made the UK Top 40 but failed to achieve the level of commercial success of her earlier works despite successful national tours (a show from her 1988 "Shouting Stage" tour was also filmed for television).

In 1989, she was the guest of Sue Lawley on the BBC Radio 4 radio programme Desert Island Discs where her favourite choice was Van Morrison's "Madame George". Armatrading's full list included Ella Fitzgerald and Gustav Mahler. Her luxury item was a guitar, while her castaway's book was Why Didn't They Ask Evans? by Agatha Christie.

In 1991, A&M released the compilation The Very Best of Joan Armatrading which returned her to the Top 10. However, her following studio album for A&M, 1992's Square the Circle, did not replicate this success and would be her final recording for the label. Following her departure from A&M, a label she had been with for almost 20 years, Armatrading signed with RCA for her 1995 album What's Inside. Despite various television appearances and a full tour (which included a string quartet in addition to her stage band), the album was not a commercial success, becoming her lowest charting studio album in 20 years. In August 1996 Armatrading performed at the Edmonton Folk Music Festival. In December 1998, she released Lullabies with a Difference, an album of lullabies contributed by her and several of her favourite artists, in honour of PACES, a charity for children with cerebral palsy.

2000s onwards
In 2003, no longer attached to a major label, she released the album Lovers Speak. Though it was her first album in eight years, it met with little commercial success. In 2004, she released a live album, Live: All the Way from America, which was a recording of a concert from her Lovers Speak tour.

Her 2007 album Into the Blues debuted at No. 1 on the US Billboard Blues Chart, making Armatrading the first UK female artist to earn that distinction. Into the Blues, which Armatrading called "the CD I've been promising myself to write for a long time", was nominated for a Grammy Award, also making her the first female UK artist to be nominated in the Grammy Blues category. In 2007 Armatrading appeared in Episode 3 of the second series of Live from Abbey Road performing "Tall in the Saddle" from her 1976 self-titled album, and "Woman in Love" from the album Into The Blues. She also appeared on Later... with Jools Holland.

In 2008, she was part of Cyndi Lauper's True Colors Tour 2008.

On 29 March 2010, she released a new album, This Charming Life. The album peaked at No. 4 on the US Billboard Folk Albums chart. She embarked on an international tour to promote it, and a concert from this tour in April 2010 at the Royal Albert Hall in London was released on the CD/DVD album Live at the Royal Albert Hall, along with two tracks from a concert in Denver, Colorado, US, in February 2011. In 2012, she released the album Starlight.

Armatrading has always supported new music and local talent. For her 2012 Starlight tour she invited 56 singer–songwriters/artists to open for her in their respective home towns before her main tour support Chris Wood. Each of the artists opening for her across the UK also had a track selected for a three disc compilation released by her record label Hypertension Music. She presented Armatrading's Singer-Songwriters, a two-part radio series showcasing these artists, which was broadcast on BBC Radio Two in February 2013.

In 2014 and 2015, Armatrading embarked on her last major tour, the Me Myself I Tour, the first to feature her solo on stage. An accompanying CD/DVD album, entitled Me Myself I World Tour, was released in 2016.

In 2016, Armatrading was commissioned by director Phyllida Lloyd and the Donmar Warehouse to write the music to an all-female production of William Shakespeare's The Tempest. Armatrading released an accompanying digital album, The Tempest Songs.

In 2018, she signed to BMG. Her first album for the label, Not Too Far Away, was released in May 2018.

In May 2021, she announced that her new album Consequences would be released later that year and shared a sample track, "Already There"; the album was released in June of that year. In 2022 she released a live album, Live at Asylum Chapel, and a book of selected lyrics, The Weakness in Me, to celebrate the 50th anniversary of her performing career.

In 2022, she composed her first classical work, Symphony No. 1; it was premiered by the Chineke! Orchestra at Southbank Centre in London on 24 November 2023. It is to be recorded for Decca Records.

Appearances and other media
In addition to recording, Armatrading has toured extensively and appeared in high-profile concerts such as "The Picnic at Blackbushe" in 1978 (alongside Bob Dylan and Eric Clapton) and The Prince's Trust Rock Gala in 1983. She also appeared in the film The Secret Policeman's Third Ball in 1987. She has also made many appearances on television, including The Old Grey Whistle Test in 1975, "Joan Armatrading: Rock Over Europe" in 1980, "Joan Armatrading in Concert" in 1982, "Late Night in Concert" in 1984, "Joan Armatrading" in 1985 and "In Concert" in 1988.

Armatrading presented a five-part series on BBC Radio 4 called Joan Armatrading's Favourite Guitarists which was broadcast in July 2009, in which she talked to guitarists about their music and their technique. She followed this up with another five-part series called Joan Armatrading: More Guitar Favourites, which was broadcast in November and December 2011.

On 19 May 2015 Armatrading appeared on BBC Two's Later... with Jools Holland, singing "Me Myself I". On 11 May 2018 she was a guest on BBC One's The Graham Norton Show and performed her new single "I Like It When We're Together".

In September 2019 Armatrading was the subject of the one-hour documentary Me Myself I, aired on BBC Four, in which she tells her life story, both as a songwriter and as a performer, with key performances from many of the musicians she has influenced.

Armatrading is a self-confessed fan of comics and actually appeared as herself in a 1983 edition of The Beano, in the "Tom, Dick and Sally" comic strip.

Style
Armatrading possesses the vocal range of a contralto. Her music draws on a wide range of influences including rock, folk, jazz, blues, soul, and reggae.

Her songs have been described as "some of the most deeply personal and emotionally naked ... of our times". In a 2003 interview, she said: "My songs aren't about me at all. They're always about love, the pain and anguish of it. But the way I've always written is from observation. They're about what I see other people going through. If the songs were about me I'd be so embarrassed I don't think I'd be able to walk out the front door." She went on to say: "the optimistic songs reveal a bit more of me because that's how I feel. I'm definitely a 'glass is half full' kind of a person." Many of her lyrics do not specify the gender of their subjects and she frequently uses the word "you" rather than a gender pronoun.

Guitars
Armatrading performs on both six- and twelve-string acoustic and electric guitars. She has played on Ovation acoustic instruments since 1973, and said this about them in an interview with the magazine Guitar Player: "I'm a bit of a hitter, you see – I bash – and I like to have everything going at once: bass, harmony, and melody. This is why I love Ovations. They are very powerful-sounding guitars, and when I hit those strings, they ring with a nice, clear, percussive – but not overly bright – sound that highlights the rhythms I like to play." She has played Fender Stratocaster and Gibson electric guitars. For her 2012–13 tour, she performed on six- and 12-string Ovations, Stratocasters, and customised Tom Anderson guitars, while for her 2014–2015 Me Myself I Tour, she performed on Ovation and Variax instruments.

Personal life
Armatrading is reluctant to discuss her personal life in interviews. In a 2003 interview with David Thomas of The Daily Telegraph, she said: "People who like my music have a legitimate interest in me, but I need to retain some privacy, not to be telling people what's going on, or what I feel. When you go home, the reason it's beautiful is because it's personal to you and the people you want to include in it."

In addition to her music career, in 2001, after five years of studying, Armatrading earned a BA degree in history from the Open University, of which she is now a trustee. Between 2005 and 2010, Armatrading served as president of the Women of the Year Lunches. She has been a trustee of The Prince's Trust since 2020 and an ambassador since 1983.

Armatrading entered into a civil partnership with artist Maggie Butler in the Shetland Islands in 2011, the day after the Shetland Folk Festival, but does not talk publicly about being gay.

Armatrading lives in Surrey, where she owns Bumpkin Studios, a purpose-built recording facility in the grounds of her home where she has recorded most of her albums since Sleight of Hand.

A younger brother, Tony Armatrading, was a stage, film, and television actor who lived in Los Angeles. He died of cancer on 10 May 2021, at the age of 59.

Armatrading was a guest at the Coronation of Charles III and Camilla in 2023.

Collaborations
Armatrading performed as a cameo vocalist for the song "Don't Lose Your Head" on the 1986 Queen album A Kind of Magic.

In 1997, she made an appearance on the charity single "Perfect Day".

Armatrading's song "In These Times" from her 2003 album Lovers Speak appeared on the compilation album Songs for Tibet: The Art of Peace which was released in 2008 by The Art of Peace Foundation.

Honours
Armatrading has been nominated three times for a Grammy Award and twice for a Brit Award as best female vocalist. She received an Ivor Novello Award for Outstanding Contemporary Song Collection in 1996. She has received honorary degrees from the Liverpool John Moores University (2000), the University of Birmingham (2002), the University of Northampton (2003), Aston University (2006), the Royal Scottish Academy of Music and Drama (2008), and the Open University and the University of the West Indies (2013). In 2022, she received an honorary doctorate from the University of St Andrews. She was appointed Member of the Order of the British Empire (MBE) in the 2001 Birthday Honours and Commander of the Order of the British Empire (CBE) in the 2020 Birthday Honours for services to music, charity and equal rights.

In October 2011, Armatrading was presented with a BASCA Gold Badge Award in recognition of her contribution to music. In May 2012, before her concert at Uttoxeter, as part of the 2012 Acoustic Festival of Britain, she was presented with a Lifetime Achievement Award.

In April 2016, she was presented with a Lifetime Achievement Award at the 2016 BBC Radio 2 Folk Awards in recognition of her "influence on a generation of singer-songwriters [as] one of the outstanding voices in British music since the 1970s".

In October 2022, Joan was made an Honorary Fellow of Newnham College, Cambridge. Delphine Mordey, Fellow and Director of Studies in Music, said: "We believe that Ms Armatrading embodies and lives the spirit of Newnham. Intellectually curious and focused on achieving her full potential, she is pioneering, inspiring, supporting and sharing."

Discography

 * Whatever's for Us (1972)
 * Back to the Night (1975)
 * Joan Armatrading (1976)
 * Show Some Emotion (1977)
 * To the Limit (1978)
 * Me Myself I (1980)
 * Walk Under Ladders (1981)
 * The Key (1983)
 * Secret Secrets (1985)
 * Sleight of Hand (1986)
 * The Shouting Stage (1988)
 * Hearts and Flowers (1990)
 * Square the Circle (1992)
 * What's Inside (1995)
 * Lovers Speak (2003)
 * Into the Blues (2007)
 * This Charming Life (2010)
 * Starlight (2012)
 * Not Too Far Away (2018)
 * Consequences (2021)

title: Joan Armatrading