De Juribus Unum
I got home from work this evening and found an ominous Manilla envelope among my mail. I assumed that it was a tax demand, since a lot of people seem to be getting them these days. But it wasn’t. It was a Jury Summons, requiring me to attend for Jury Service at Cardiff Law Courts, one of the fine civic buildings in Cathays Park, at a date in November 2010. I was relieved (that it wasn’t a tax demand) but also strangely excited. I’ve never actually done Jury Service, you see, and I quite enjoy the odd courtroom drama on the telly. Since I don’t actually have any lectures this semester I think I might as well get it over with, rather than asking for a deferral.
Incidentally, Question F on the form upon which one has to reply to the Jury Summons asks (sic):
Do you currently have, or have had in the past, any disorder or disability of the mind?
Do you think if I correct their grammar they’ll think I’m a busybody and let me off?
Anyway, in anticipation of the forthcoming excitement, I thought I’d post this clip from one of my favourite old movies, 12 Angry Men, starring the great Henry Fonda which delivers an object lesson in how to deal with prejudice.
I’m sure the real thing is nothing like this, of course. The only true tale I can remember was a former colleague of mine who was on a Jury that acquitted a young man of being a drug dealer on the grounds that the quantity of marijuana he was carrying was so small it must have been for his personal use only. The amount concerned was 12 ounces…..
Any readers with other juristic anecdotes to share? If so, you know where to put them. (I mean, in the comments box.)
In the Dark 
September 14, 2010 at 4:17 am
I actually did laugh out loud when I read this.
I wonder if they know what they’ve got themselves in for in a few months time.
I imagined a Peter Coles in white “Henry Fonda” suit scribbling away on the blackboard of jury room B, explaining to those assembled about the prosecutor’s fallacy, non-gaussian distribution functions, Bayesian methodology and conditional probability P(M|A) before asking for a brief interval so he can do a Kolmogorov–Smirnov significance test and then run some monte carlo simulations on his laptop!
I can only say I’m just very glad I haven’t commited any crimes in the Cardiff area recently.
ps. 12 angry men is great but I much prefer the similar-themed “The Ox Bow Incident” which also stars (a very young) Henry Fonda in a similar role. I’ve seen Clint Eastwood describe it as his favourite film ever.
September 14, 2010 at 8:24 am
..not to mention asking the judge what “reasonable doubt” actually means: 5%, 1%, 0.1%….?
I’d probably be more like Tony Hancock than Henry Fonda. In the classic Hancock’s Half Hour Twelve Angry Men he delivers the brilliant line:
September 21, 2010 at 12:03 pm
The concept of probability was not invented in the 17th century when its mathematical laws were first written down; it was simply quantified at that time. Before then it had been developed principally in the Law, because the law is concerned (in modern language) with the probability that somebody is guilty or innocent given the evidence; and Law is a key component of civilisation. All of the 7 men most involved in the early mathematical development of probability were either lawyers or sons of lawyers.
Although the first applications of the new theory were to gambling, that was simply a selection effect, because gambling provided examples simple enough to be tackled by the first generation of quantifiers, yet complex enough to defeat unaided intuition, while being familiar to most readers of the time.
There is no prospect of giving numerical probabilities to innocence or guilt in real court cases – human affairs are too complex to be quantified. Even DNA evidence gives only the numerical probabilities of getting the observed traces supposing that the accused is innocent or guilty, not the probabilities of innocence or guilt given the traces; to get to the latter, these numbers must be combined wtih human factors too complex to be quantified. A jury needs to be given those factors and then given a feel for the strength of the numbers coming from DNA evidence, eg by relating it to the number of people in towns or sports stadia of various sizes; then the jury should be left to make their decision. What should *not* be done is to try to get the jury to think of those ‘prior’ human factors in terms of football crowds etc, then require them to do a calculation (Bayes’ theorem) in order to combine that with the DNA numbers. An expert witness rightly came unstuck in court by advocating that strategy.
Fairly soon, DNA testing will reach the point of uniqueness for all persons except identical siblings, and matters will become simpler again (aside from contamination issues).
Anton
September 21, 2010 at 2:37 pm
The outstanding book on pre-quantitative probability and its development is: The Science Of Conjecture by James Franklin. The title is a play on Ars Conjectandi (The art of conjecture) by James Bernoulli, which was one of the pioneering quantitative treatises.
September 14, 2010 at 8:36 am
Reasonable doubt has an operational definition. It is the level of doubt that 12 citizens would agree on as reasonable. This is incredibly practical as it allows a conclusion to be drawn without half baked and misleading attempts at quantifying things we don’t have the sufficient data for, which of course as a cosmologist you would know all about.
September 14, 2010 at 8:41 am
Hush.
September 14, 2010 at 2:50 pm
Although I had read that (at least in the UK) the phrase “reasonable doubt” is no longer used in court – I’m not sure if that is true.
But yes, the question “what is the probability of a reasonable doubt?” can be flipped round to “how often are we happy for juries to get it wrong?”. It is really the same question asked in a different way.
Richard Dawkins once wrote a brief essay trial by jury where he makes the point that almost the worst thing you can do with 12 jurors is lock them in the room together to discuss the issue, because then their decisions are no longer independent.
I only remember this article because I read it the year I turned 18 and friends were starting to get called up for jury service.
September 21, 2010 at 12:13 pm
The whole point is that members of the jury are meant to influence each other – but there are good and bad influences. Good influences involve members of the jury *educating* each other (“Thank you – I hadn’t realised that point!”) Bad influences are of the type perpetrated by the father of a friend when acting as a jury foreman, who told the other members of the jury to refuse to speak to the lone dissenter until he changed his mind and the verdict was unanimous. This dirty trick soon worked.
September 26, 2010 at 1:42 am
but it’s hard to argue against the suggestion that 12 jurors are split into 2 teams of 6. The two teams having no influence on, or contact with, each other during either trial or deliberation.
If they reach the same verdict independently, that is a far more robust result than anything a group of 12 can produce unanimously.
Perhaps 3 teams of 4 would be better still.
September 14, 2010 at 3:24 pm
The question on the form is really..hilariously funny.
Good luck for all of this issue : )
September 14, 2010 at 3:26 pm
How do you suggest I answer it?
September 21, 2010 at 11:02 am
I suggest that you say that if you did have a disability of the mind then your mind would not be aware of it, would it?
September 14, 2010 at 10:59 pm
All this talk of Twelve Angry Men turned my mind to Humph:
“The expert’s expert was, of course, Lionel Blair. Who could ever forget opposing team captain, Una Stubbs, sitting open-mouthed as he tried to pull off Twelve Angry Men in under two minutes?”
September 15, 2010 at 8:14 am
…or indeed the look of determination in his eyes when he went down on his knees to finish off Two Gentleman of Verona?
September 22, 2010 at 4:49 pm
I’m continually appalled at the juror in 12 Angry Men who changed his vote because he wanted to get to a baseball game.
Shocking. Of course, if it had been a cricket match…
September 15, 2010 at 11:12 pm
I was called up for jury service at the Cardiff central law courts as a PhD student. I was in the final two months of my 3-year studentship, had received my last studentship funding payment, and still had a lot more work to do on my thesis project. There was a lot of sitting around waiting to learn whether we were going to be assigned to court cases. In those days each defendant in each case could object to two (or was it three?) jurors and have them replaced, which meant that far more people had been called to serve than would actually sit on juries. The main case taking place was an appeal in a much-publicised drug smuggling case involving a large gang which had been working in Pembrokeshire. Not all of us in the pool of potential jurors were needed. I was asked whether I wanted to sit on a jury, and requested not to so to get back to my PhD studies.
Some of the time was wasted, but I managed to spend much of the dead periods productively. I had been lucky enough to meet Bernard Pagel a few weeks earlier and he had recommended some important papers on the chemical evolution of galaxies to get me introduced to the subject. I therefore spent the dead time reading research papers and rederiving equations.
It would have been very interesting to have served as a juror, but the constraints on my time were acute.
So take some reading material with you, Peter.
September 16, 2010 at 9:43 am
..and a few crosswords, I think.
September 21, 2010 at 11:04 am
Jury service, Yes please – a chance at last to read the 4m words of Will Durant’s History of Civilization…
September 27, 2010 at 5:38 pm
I’m a bit disappointed to have to have today received a letter stating that the Jury Summons that was served on me has been withdrawn owing to my “status” and that I don’t need to attend court or take any further action.