I guess you are back from your summer vacation by now. Did you have a good time? Kicking it back with a nice crime novel in the hammock perhaps?
I love crime novels and read a few this summer. It struck me that a crime novel is actually a pretty good example of a configuration problem.
Let me explain.
Most crime novels tend to follow a certain, recognizable pattern. It always starts with someone getting murdered in the beginning. Our hero (the detective) arrives to the scene and we start getting the background details. At this point you have no idea who the killer is, what the motive is or, sometimes, what weapon that was used.
These three factors (Who? With what? Why?) create the whole setup for the plot. The possibilities and combinations seem endless but only one solution will be true in the end. It is up to our hero to find that solution (and up to us as readers to try to figure it out before him or her).
This could be brought down to plain mathematics: In an ordinary crime novel let us assume there are on average 20 people introduced to the plot that could possibly be the killer.
Usually the weapon is revealed (by the forensics) rather early but let us says there could be on average 10 different murder weapons. The motives are usually endless but some common ones come to mind are: jealousy, money, family grudges reasons, pure evil. There are probably a lot more so let’s round it up to some 100 potential motives.
On any given detective story now there would be a ”data set” of 20*10*100, creating some 20.000 scenarios!
Clues are rules and constraints
With that many scenarios we are lucky to have our detective at hand and this is when this turns into a configuration problem. He or she starts deducting clues and observations and creating rules (constraints) about the plot.
The neighbors did not hear anything when Ms. Johnson got killed?
This rules out any noisy weapons and prolonged assaults, i.e. weapons with the attribute ”noisy”.
The house showed no signs of break in?
This rules out any killer who did not know the victim. This, in turn, rules out all motives that are”stranger related” like serial killers etc
They found foot prints of size 46 in the blood?
This rules out any child (age < 18) and any woman (gender: male) since it most likely a large man. At this point of the story, the only large men that knew the victim and had access to ”silent weapons” were the Priest and the Husband- the plot thickens!
Every clue that the detective comes up with narrows the options down and brings us closer to the solution. Just like a configurator, each clue closes the trail of numerous consecutive options or ”outs” left until our hero finally ends up in a close encounter with the killer: probably a Grand Finale at an abandoned house by the sea!
Reading crime novels the Tacton configurator way
If you would read your next crime novel with a configurator at hand, you would always have one possible (the most likely) solution at hand. This configuration of possibilities would then change with every clue and observation. With every constraint applied you would not only know who is the most likely to be the killer, but also who still are suspects. You would also always know who to rule out as killers and what motives and weapons that would be impossible.
Even though it would be a fun experiment to test, I believe this would be an example of not knowing is more fun than knowing. Don’t you agree?