01 March 2010

A tale of universal parsimony

In Karel Čapek’s Tales From Two Pockets there is a detective captain Dr. Mejzlik who appears in a few of the tales. In one of them, while he and the historian Divisek are trying to solve what they think is a murder mystery from 1465 using only a handful of historical facts and a clue from a tombstone, Mejzlik explains their "basic rule of methodology":

Now first of all, any hypothesis we advance must take into account all of the known facts; nothing, not even the slightest circumstance, can be allowed to contradict it. In the second place, these facts must be arranged into a single, continuous action; the simpler, the more contained and connected the action, the more likely that things happened exactly that way and not otherwise.
What Čapek had his character espouse is, of course, the general methodology of all scientists, including what may be called the principle of parsimony, which presupposes that when everything else is equal, the simplest theory among competing theories is likely to be the correct one.

Čapek's stories date from the late 1920s. In 1992, Peter Atkins wrote in Creation Revisited:
The only clue we have at the outset is that the final answer will almost certainly be one of extreme simplicity, for only the perfectly simple can come into existence while all agents asleep (or are not there). This suggests that we should examine the universe for the footprints of its underling simplicity.
Atkins was also trying to solve a mystery, albeit one that is a bit more grandiose: the creation of the universe. Nevertheless, the basic methodology of both scientists is the same and reduces to the perception of the simplest that can explain the most.

Mejzlik would have approved of Atkins' method. However, although Mejzlik solved Divisek's mystery, Čapek hints at the end of his tale that the duo hadn't followed "proper scholarly methodology". Perhaps, what they lacked was sufficient data. Then again, scientists trying to explain historical events rarely ever have enough information, but must often rely on statistical reasoning. It seems that we can not be sure of the causations of even the simplest happenings.


fred schueler said...

"Simplex sigillum falsi." Bunge (1963, the Myth of Simplicity) -- http://pinicola.ca/kitchen.htm -- the motto that sets one up for studying natural history.


I don't think the working hypothesis is that everything is ultimately simple. I think what Atkins at least is saying is that even when a phenomenon is complex we need to dissect out the simplest components & explain those & then build the rest on top of them.

Will reductionism ultimately fail us?