You have a free choice, I tell my students as I start them off on their individual research projects - up to a point. What's the point, they inevitably ask. I have a little list, I say, of taboo topics. It is relatively short, but the prohibition is absolute.
My list has been drawn up in the light of hard experience. This shows that none of the banned subjects can be written about in the balanced, objective and dispassionate manner that the project is meant to nurture.
Item number one is anything to do with the Mafia. As there are many mafias now in existence, the ban has to extend to them all. I have noticed that projects on this subject tend to be written by 19-year-old males with 13- year-old brains. As such they exhibit the keenest of interests in all matters technical, such as models of luxury cars, calibres of weapons and gradations in quality of illegal drugs.
Strangely, the Mafia's chief "products" - murder, intimidation, corruption, blackmail, theft, extortion, people trafficking, prostitution etc - are ignored or glossed over. Either that or they are glamorised, and the details lovingly listed in a spirit of thinly disguised admiration.
Only one crime boss is mentioned by name on the Jones blacklist: Pablo Escobar, the Colombian drugs baron who made it to number seven on the list of the world's wealthiest men. As with the Mafia generally, there is a certain type of young man who is determined to prove that Escobar was a cross between Mother Teresa and a Scout. To this end, their projects tend to concentrate on his philanthropic works - of which there were many - and overlook the 30 judges, 450 policemen and countless others who were killed either personally by the philanthropist, or on his orders.
Along with the Mafia, I have also had to call a halt to all projects on unidentified flying objects, more commonly known as UFOs. This topic, too, has the capacity to instantly turn any student's critical faculties into marmalade. I am perfectly prepared to accept that UFOs exist - any moving light in the sky you can't immediately recognise is, by definition, unidentified. Trying to persuade an impassioned young person that that's not the same as asserting it's an alien craft full of quasi-hominoids with pointy ears and petrol pumps for noses is another matter.
As night follows day, any project on UFOs very quickly heads into the territory of government cover-ups and how "they" will only let you know what "they" want you to know. Given the propensity for even the smallest of secrets to leak into the public domain, I need some convincing that the world's collective governments regularly impound flying saucers.
Various conspiracy theories are also behind most of the other topics that I no longer wish to read about. Call me naive, but if you are being driven in a built-up area at 90 miles per hour by a drunken driver, then the chances of an accident must surely be quite high. Most, but not all, the students who propose writing about Princess Diana are female. Can they be objective in their sifting of the mountains of material that exist on this? Can they hell? "She was a lovely woman and `they' were always out to get her," is the nub of it.
Where the conspiracy theorists really have their field day is with 911. Clearly, I must have been walking round with my eyes shut, as it was only a couple of years ago that I came across the 911 denial phenomenon for the first time. A student was trying to convince me that when I saw planes flying into the twin towers I wasn't really seeing aircraft at all. That was simply what "they" wanted me to see.
Then he turned his attention to the explosion at the Pentagon. This wasn't caused by a plane either, he confided, but a missile fired by the US military. The explosion was not big enough for an aeroplane to have caused it; the hole in the Pentagon wall was too small.
Did that mean, I asked in a moment of inspiration, that American Airways Flight 77 was even now still flying about somewhere in the ether, as it had never returned and neither had its passengers and crew?
I suspect that the conspiracy theorists have an answer to this question, but I couldn't think of it at the time. More to the point, neither could my student.