Tuesday, 26 June 2012

The Turing Joke Test

This past week we've been celebrating the centenary of the birth of Alan Turing. In Cambridge there have been several lectures and events culminating in the unveiling of a blue plaque outside King's College, where he was a student and then fellow for many years. Turing is remembered for various things: for his mathematical theories that led him to be hailed as the father of modern computing; for his wartime work at Bletchley Park; as a victim of prejudice on account of his sexuality. Like I suspect many people, though, I first encountered his name as the eponym of the Turing Test. In a famous thought experiment, Turing asked how true artificial intelligence might be identified. His answer: if a machine could respond to questions in such a way that its interlocutor is unable to detect that it is a machine rather than a human being. An artificially intelligent device ought to be able to think, or at least react, like a normal person.

I doubt that the English justice system would be able to pass the Turing Test. Celebrated as the guarantor of our ancient liberties - a barrister with the unfortunate name of Harry Potter described it in a recent BBC Four documentary as the country's greatest gift to the world - English law is also capable of bovine stupidity, lack of perspective, literal mindedness, rigid adherence to procedures and a remorseless (but quite logical) following up of an initial flawed premise to an absurd and unjust conclusion. All characteristics of machine intelligence. Added to this, recent years have increasingly seen an eschewing of discretion in favour of procedural regularity and unthinking conformity to rules and guidelines.

Tomorrow sees the beginning of the culmination of the Twitter Joke Trial, as for the second time the Divisional Court considers the legal principles on which Paul Chambers was convicted for sending a Tweet. Two high court judges having failed to agree earlier this year, a new panel of three will convene, headed by the Lord Chief Justice, no less. Do I need to rehearse the facts? Probably not, but it's worth remembering that it is now almost two-and-a-half years since Chambers, frustrated by the closure of Robin Hood Airport in Doncaster, sarcastically offered to blow it "sky high". The Tweet was discovered by an airport manager, who instantly recognised it for the joke that it was but felt that the rules required him to pass it to the police.

The police also instantly recognised it for the joke that it was but felt that the rules required them to arrest and question Paul Chambers and later to pass a file to the Crown Prosecution Service. The CPS recognised it for the joke that it was but felt that the rules required them to bring a prosecution "in the public interest"; and after much searching, they found a then obscure law that enabled them to do so.

A magistrate, who recognised the Tweet for the joke that it was, thought nevertheless that it was "menacing" within the meaning of s.127 of the Communications Act 2003. Chambers was fined, charged costs and lost his job. A crown court judge upheld the conviction, while recognising the Tweet for the joke that it was. That exhausted any avenues for appeal on the grounds of fact or justice - for example, the plain absurdity of regarding as menacing a statement that no-one, at any point in the proceedings, regarded as anything other than what it was, a humorous expression of a natural frustration. Instead Paul's legal team, among whom David Allen Green has long been prominent, must identify a bug in the system. They believe they have found one, and will argue that the lower courts were wrong to look up the word "menacing" in dictionaries, and should instead have consulted their law books, where a special, more restrictive definition may be found.

This may just work. Whether or not it does may come down to how the court decides to balance justice in a particular case (which would require the conviction to be set aside) against the general usefulness of Section 127. If "menacing" were to be defined too narrowly, it might set too high a bar to allow for the conviction of trolls, racists and bullies who have in recent months been the target of increasing police and prosecutorial activity. At least, I suspect the court will need to be persuaded that this would not be the case. Formally, this is a technical issue of legal definition. In practice, the implications are much wider.

The current CPS guidance states that s. 127:


- targets false messages and persistent misuse intended to cause annoyance, inconvenience or needless anxiety [my italics]

- can be used as an alternative offence to such crimes for example as hate crime (including race, religion, disability, homophobic, sexual orientation, and transphobic crime), hacking offences, cyber bullying, cyber stalking, amongst others.


Such issues have achieved a much higher public profile in the past few months, which have seen (among others) the conviction of Sean Duffy for posting an offensive, doctored image of a teenage shooting victim; Frank Zimmerman for making threats aimed at Louise Mensch MP and her children; and Liam Stacey for making racist comments on Twitter about Fabrice Muamba (though he was charged under the Public Order Act). Likewise, in the wake of last year's riots, people who posted incitements on Facebook received draconian custodial sentences despite no actual damage being caused as a result of the postings.

None of these cases - do I even need to say this? - were in any sense comparable to Paul Chambers', who had (as everyone has always accepted) no malicious intent. Nevertheless, the readiness of the authorities to prosecute, and the severe (some think excessive) penalties that have been handed down, are indicative of a strong official desire to crack down hard on abuses of social media. The past year has also seen the outbreak of some particularly violent and vindictive Twitter wars, sometimes with real-world consequences, in which the police, willingly or otherwise, are increasingly becoming involved.

It would, though, be wrong to describe Paul Chambers as a victim of this mentality. His case long predates the recent ones. So rapid is evolution in electronic media, indeed, that two and a half years seems an awfully long time. The Twitter Joke Trial is really a relic of an already bygone age, when many people (including many involved in the justice system) had never heard of Twitter and even some of its users didn't know quite what to make of it. The problem then was that judges didn't really understand social media. Now, by contrast, the problem might be that they think they understand it only too well.

Paul Chambers was prosecuted under a little-known and underused provision, largely untried in practice, essentially because the CPS needed to justify their and the police's use of resources by charging him with something. Since then, s.127 has proved all too useful. But not in his kind of case: there have been no more Twitter Joke Trials, though there have been trials of people who claimed to be joking. Most human beings have no trouble telling the difference. Getting the law to make such obvious and (to us) intuitive distinctions of context and nuance is a real test, but one that we should all expect a truly intelligent legal system to pass.