If there's an outbreak of thievery should the authorities pursue the makers of ladders or chisels because burglars use them as tools of their trade? If there's a spate of armed robberies, should gun makers find themselves in court?
The question is whether or not the software firms are to blame
The argument - if provocatively put - is central to the grand dispute before the Supreme Court between the entertainment industry in the form of 28 music and movie companies and two producers of file-sharing software.
Grokster and Morpheus are the two programs in the sights of the industry because they're used to distribute songs and films with no royalties being paid to the artists or anyone else involved in the production.
But the legal point is that Grokster and Morpheus aren't the downloaders - or thieves as the industry sees them. They merely provide the software used by the downloaders.
And at Tuesday's hearing, the justices of the Supreme Court were clearly alert to this point.
They wondered aloud whether similar lawsuits in the past might have discouraged inventions like photocopying machines or portable music players or video-cassette recorders, all of which can be used to make illegal copies of copyrighted material.
There is a legal precedent which the entertainment industry has to confront.
The challenge is to find equitable ways to share the creations of the gifted
In 1984, the industry tried and failed in court to block the development of the Sony Betamax video recorder because it could be used to make pirate copies of films.
The judge ruled that Sony couldn't be held responsible for the use to which its products were put. It's a close but not exact parallel with this week's case.
Apart from anything else, it was not clear that the overwhelming use of Betamax recorders would be for piracy.
In the current matter, much will probably turn on how much a product can be used legitimately compared with illegitimately.
Nobody would try to get ladders banned because burglars used them - a lot more people use them for completely legitimate purposes. Video recorders and photo-copiers have many legitimate uses too.
But few would dispute that Grokster or Morpheus are used primarily for distributing copyrighted works for free, which otherwise would earn payments for the artists and production companies.
The software is used overwhelmingly to download versions of new releases. Few but not everybody would dispute that.
The Grokster and Morpheus software companies say their programs can be used also for distributing documents or offering free songs legitimately or making old, out-of-copyright material available.
Rights and wrongs
They and their allies also argue that to give the industry its way would be to block technological development.
Any innovator would be deterred by the threat of lawsuits from film and music companies who argued that the innovation would enable people to take songs or films for free.
But the Supreme Court justices were alert to this argument too.
Justice Anthony M. Kennedy asked one of the software companies' lawyers whether profits made from trafficking in stolen goods could be used rightfully to finance a young technology company.
"That seems wrong to me," said the judge.
Whoever wins, some things will not change: if artists don't get paid, they will be less likely to write or perform.
But, if free music is available, people will take it whatever the rights or wrongs.
Is file-sharing compatible with the commercial requirements of artists and the entertainment industry? Let us know what you think.
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The views below reflect the balance of opinion received so far:
File Sharing is a necessity, not for the criminal usage to which it is put by a large number of its users, but for research and education.
This software is essential. It makes sharing research and transferring vital information 100 times easier and there is a vast stock of out-of-copyright material that can be legitimately file-shared.
The onus should be on the industry to protect their own material better. Those who run sites allowing for illegal file-sharing should be punished, but those who make the software are not to blame.
This is technological oppression by big firms who will then produce their own versions (worse versions at that, no doubt). The Supreme Court can either strengthen the freedom they allegedly hold so dear or give one more iota of it away to Corporate America.
Alex Grant, Reading, United Kingdom
Perhaps the music and film bodies should look at making the legal versions cheaper; I'd buy more DVDs and CDs if they weren't so extortionately priced.
Richard, Leeds, West Yorkshire, UK
There are perfectly legal uses of this technology. Take for instance World of Warcraft, one of the biggest selling online games with 1.5 million users worldwide.
It uses Bittorrent for distributing all its new content and patches.
The Entertainment industry needs to embrace the new methods of distribution, with low distribution costs, and produce content that is cheap, easy and uninhibited with Digital Rights Management.
And while they're at it, the could stop stealing from the public by constantly trying to extend copyright laws. All that does is allow companies to keep generating profits on old media, stifling innovation and giving no impetus to create. Disney is a case in point. When was the last film they actually produced themselves - as opposed to badged, like the Pixar ones.
People made songs long before there were worldwide distribution deals and world tours, so I don't see that file sharing means there are less songs.
Perhaps so called pop stars could manage to survive without multi million pound incomes and write for the love of it, and perhaps we will get better music too.
Brian, London, England
The question of whether file sharing is compatible with the commercial requirements of artists is distinct from the interests of the entertainment industry. Artists produced long before the development of the entertainment industry, they will continue to do so after any possible demise.
As to whether file sharing is compatible with the commercial requirements of the entertainment industry there are three reasons why we and those in the industry shouldn't be overly concerned:
Firstly, any decline will be gradual enough (serious downloaders are still in a minority, one that is limited by broadband availability, technical ability and societal acceptance) for shareholders and interested parties to get out in time.
Secondly, the entertainment industry will diversify into new revenue areas that internet piracy cannot infringe on (such as nice fancy DVDs with all the extras in the box, or live performance).
And thirdly, even if the entertainment industry is rendered commercially unviable by piracy, it's a pity in the same way that it's a pity that the 'industry' of monastic calligraphy was rendered unviable by the printing press. As Marx would have it, technological advances determine the nature of the society built on them and there's no point fighting against inevitability.
Stephen Sullivan, Leamington Spa, Warwickshire
I feel that the record companies themselves need to decide who is responsible for the breech of copyright. They are prosecuting both the user and the producer of the software for alleged copyright infringement.
Surely if the copyright has only been broken once, that is one copy has been made, then two separate individuals cannot be prosecuted and the compensation claimed twice.
Theft is theft, but that's not what the issue is here, it is whether these software writers are aiding and abetting the thefts.
If I were the judges I would want proof that at least 25% of all traffic was legitimate and that the software warned against illegal copying every time it was used.
Then I would be satisfied that the writers were not aiding and abetting copyright theft.
David, Northants, England
First of all copyright infringement is not theft. This is very, very important.
Anyway, returning to the proper argument; I've just downloaded through a peer 2 peer file-sharing network a 250mb 'free' and legal game, Wolf ET 3D, from ID software.
This wasn't free when it came out, but became so after the makers realised no one would buy it. Note, you will never see this in a shop for free as CDs cost money. Hosting it on a website costs money. File-sharing network such as Bittorrent costs almost nothing. If the networks are closed down, this will not happen again.
First of all, contrary to what Adam said earlier, copyright infringement is most definitely a crime and carries a maximum sentence of 10 years in the UK. Theft by comparison is a minor crime that rarely merits a custodial sentence. (I don't agree with the system, it's just the way it is.)
However, I have to side with the software developers on this one. The record companies can spend more money on security measures, but they don't want to, or they could go after the people actually sharing their music, but the companies don't want to alienate their (potential) customers, so they go after the software companies.
The gun analogy is a good one. There are small, automatic machine pistols that are favoured by drug gangs because they cause massive carnage and are easily concealed. So, many states banned them and the gun companies stopped making them, problem solved.
If the sharing software is really so dangerous, then make it illegal (if the government had the guts). Or else, just let them sell it and leave the moral decision where it should be, in the hands of the people.
The software companies are liable in the same way car and beer companies are liable for people driving whilst drunk - that is not at all.
There are legitimate uses for the software, but, as with all things, some people will use them to break the law.
There were no copyright laws during the Renaissance, yet people did in fact create great works of art. The argument that copyright is essential for creativity is spurious and should be put to rest.
, New York City, USA