Massimo Piglucci, a philosopher who has long studied the Holmesian canon, describes Holmes’ method as a form of “eliminative induction,” because “deduction” is too limited to encompass it. Holmes, he says, actually works his way through inferences toward the best explanation by considering and discarding others. He uses whatever seems best for the occasion, picking “the right set of tools from a broad toolbox, depending on the characteristics of the problem at hand.” Holmes does use intuition, Piglucci observes, but he combines it with time-tested practices.
There’s nothing wrong with forming a guiding hypothesis, as long as one stays flexible and accepts that it could change with new facts. The real problem lies with the arrogance of believing that one is always right or superior to anyone else, as well as deciding that someone is guilty before the evidence proves it.
I agree that we should be careful about some of Holmes’ statements. One that I've found troubling is, “Any truth is better than indefinite doubt.” Really? Any truth? This pressures us to contrive an explanation that sounds right and achieves closure. That’s how many investigations mess up. Better to leave an investigation open than to tie it up prematurely with something that might seem true.
I agree the statement is wrong, but it does say something interesting about psychology. Hardly anyone is content to have no explanation at all. They must always have something, even if it comes with massive caveats. Rickety bridges are acceptable, gaps are not.
I also quake at this one: “When you have eliminated the impossible, whatever remains, however improbable, must be the truth.” As if any given investigator can think of all possibilities and effectively eliminate all impossibilities. What if they don’t have all the facts or don't realize the limits of their own imaginations? They might erroneously decide they’ve done everything possible when they haven’t. I’ve seen this, too. It’s the fallacy of believing that all the facts you know are all the facts there are.
Which is a very important fallacy and nicely phrased. However, I read the original statement more to be about principle than method. Improbable things shouldn't necessarily be rejected, as the author explains :
To be fair, Holmes has some good advice, too, such as, “It is a capital mistake to theorize before one has data. Insensibly, one begins to twist facts to suit theories instead of theories to suit facts,” and “We balance probabilities and choose the most likely. It is the scientific use of the imagination.” He also claims that the “first rule of criminal investigation” is to “always look for a possible alternative and provide against it.”
https://www.psychologytoday.com/gb/blog/shadow-boxing/201805/sherlocks-curse
Thinking one has access to all the possible hypotheses is truly damning.
ReplyDeleteIt is for this same reason I spend time telling people how useless deduction is in the real world. Deduction is worthless as a way to form new beliefs. I has some small merit as a heuristic for comparing competing beliefs, and somewhat greater merit for combining non-competing beliefs... but it is completely useless for incorporating evidence and forming new beliefs.
I like 2 of Feynman's quotes on the limits of imagination and thinking you've exhausted the space for hypothesis-forming:
ReplyDelete"The imagination of nature is far, far greater than the imagination of man"
and
"It is surprising that people do not believe that there is imagination in science. It is a very interesting kind of imagination, unlike that of the artist. The great difficulty is in trying to imagine something that you have never seen, that is consistent in every detail with what has already been seen, and that is different from what has been thought of; furthermore, it must be definite and not a vague proposition. That is indeed difficult."
I came here because I saw Feynman in a comment.
ReplyDeleteIn high school, I was on a debate team. The coach always said "You'll never have the complete truth at your disposal, ever." Which is exactly congruent with It’s the fallacy of believing that all the facts you know are all the facts there are.
ReplyDeleteI used to balk at that statement, kinda still do. But if I held it in my mind's eye, it allowed me to absorb an opponent's argument as a different perspective on the same problem domain - and I'd be watching for internal contradictions. But the greatest weakness of any bad argument is attempting to present opinions as facts.
That's where Sherlock Holmes always gets in trouble and it's the most tiresome aspect of any detective story. Agatha Christie is especially guilty in this regard: the scene opens with a few bars from Beethoven's Pastorale, a nice quiet bit of Devonshire, a placid pond of a place into which someone throws a rock - and we spend the rest of the novel watching the ripples spread out from where the rock struck the water. I can no longer read detective novels, but others enjoy them, forming their little misguided opinions about who's the Guilty Party on the basis of pleasant if fallacious reasoning.
Actual detectives have far more serious problems than the inductive heresies of Sherlock Holmes. Their paychecks are issued by the same outfit which pays the prosecutors - despite all the laws and procedures and ethical considerations involved in the discovery process, exculpating evidence is often suppressed to help the prosecutor's conviction rate.
The genre conventions of the classic murder mystery are famously narrow - it's like an extremely tightly defined poetic structure, crafted to establish certain expectations in the reader's mind.
ReplyDeleteSo yeah, trying to apply Holmes to the real world is best done with great caution, flexible goals and a big barrel of salt.