Sherlock Holmes and Philosophy Part 12

Alias Sherringford Hope?

Doyle originally christened Holmes as Sherringford Hope, a surname that for a variety of reasons would have been ironic.

In "The Adventure of the Second Stain" an important letter is entrusted to the Secretary for European Affairs, Trelawney Hope. Should this letter fall into the wrong hands, its contents could be used as an excuse to start a war. At night Hope puts the letter in his bedside box, surely a poor security practice. Indeed the letter is stolen from that very box. When Holmes later locates the letter and secretly returns it to the box, Hope is so happy that he unquestioningly accepts its magical reappearance. It turns out that Hope's wife, whom Watson describes as "the most lovely woman in London," had stolen the letter. She had taken the dispatch because she was being blackmailed. Holmes points out to her that had she confided to her husband about this matter, none of this needed to happen. She, however, views the situation emotionally and does not believe that a reasoned conversation would have solved the problem. In short, we have Hope described as irresponsible (who would bring such an important doc.u.ment home?), child-like in his acceptance of "magical" events, beautiful but irrational and entirely emotional (Mrs. Hope).

In A Study in Scarlet we meet another character named Hope, this time it's Jefferson Hope. In this story, Hope is a vengeful killer, who murders two men before himself dying. He suffers from an aortic aneurysm, but stays alive long enough to kill his two sworn enemies. To kill each man, he carries with him two sets of two pills, one poison and the other harmless. He offers each victim a chance to choose a pill, so that it is G.o.d who decides who shall die-thereby evincing Leibniz's claim that G.o.d and hope are connected. The first man follows Hope's demand, and chooses the poison. The other, however, refuses to play along, and Hope stabs him in the heart.

Here is what we learn about Hope in this story. Hope's true love, prevented from marrying him by these men, dies of a broken heart without Hope. G.o.d, at least a vengeful G.o.d reminiscent of the Old Testament G.o.d, sides with Hope. Hope can pierce your heart, and die happy. Nonetheless, it is important to remember that Holmes tracked down Hope and brought him to justice, thereby setting Holmes up contrary to Hope. In the end, Hope left four people dead (including himself), and did not leave an example of hope for others to follow.

Facing the Truth.

"The Adventure of the Veiled Lodger" ends with Holmes believing himself to have prevented Mrs. Ronder's suicide. Holmes's explanation for her life's use should not have struck Mrs. Ronder as helpful. Until she unveils herself in front of Watson and Holmes, we're told of only two people who had seen her face, namely Mrs. Merrilow and a milkman, both of whom saw it accidentally. Unless Holmes is suggesting that Mrs. Ronder move to High Street and sit like a mannequin in a shop window, the only chance for her story to reach the world would be via Dr. Watson, a possibility to which we will return.

Whether Mrs. Ronder is an atheist or a deist is not a question about which we're likely to be able to make any progress. Whichever may be the case, Mrs. Ronder resembles a postmodern, someone living in an age characterized by Nietzsche's proclamation that "G.o.d is dead," by which he means minimally that G.o.d no longer plays a crucial role in our lives. It does not follow, however, that she accepts the theological claim, and thus must abandon all hope. Rather, hope is crucial to Mrs. Ronder.

The nagging question is, Why would Mrs. Ronder contemplate suicide now? It seems reasonable to think that her desire to commit suicide would have been most pressing shortly after the catastrophe. After all, that night began with the promise of ridding herself forever of her abusive husband and starting a new life, one rich in emotion, with her lover. The night ended with her being alone in the world and scarred in a way that ensured she would remain alone the rest of her days. She has been Mrs. Merrilow's lodger for seven years, so at least that much time has pa.s.sed since the fateful night when her lover failed to protect her, and it became necessary to veil her once beautiful face. Presumably the desire to commit suicide would gradually wane, and so it is curious that she would consider killing herself now.

The most direct reasoning is as follows. The idea of confessing what happened that night appeals to Mrs. Ronder. She would like to do it before she dies, she tells Mrs. Merrilow. The reason she has not talked to anyone about the events so far is that her lover, who would've been implicated by her confession, remained alive. His recent death frees Mrs. Ronder to tell her life story. Having told Holmes and Watson what really happened, she was then free to kill herself, something that Holmes sensed.

This story line is complicated by Mrs. Ronder's selectivity in choosing her confessor. Mrs. Merrilow initially proposes that Mrs. Ronder talk either with a member of the clergy or with the police. Mrs. Ronder's objection to the police is interesting in that she does not object to them per se, nor does she mention that she would not want to be incarcerated. While she tells Holmes that she has not long to live, which presumably mitigates the threat of incarceration, the problem lies with the public. She does not want a scandal and publicity, as these would interfere with her wish to die peacefully. While ostensibly a good reason at the time-at this point in the story the reader a.s.sumes she has a terminal disease-we later learn that her death is imminent only because she plans to make it so.

While her dismissal of the suggestion to talk with the police is understandable, her reasoning about the clergy is not particularly cogent. She rejects Mrs. Merrilow's suggestion that she speak with a clergyman because "the clergy can't change what is past." While of course true, it isn't uniquely true of the clergy. No one can change the past, not even Sherlock Holmes. Her stated reason for selecting Holmes is that he is a "man of judgment," something that also seems true of the alternatives Mrs. Merrilow proposed, namely a clergyman or the police. While she might mean understanding, independent judgment, Holmes's response of "I do not promise you that when you have spoken I may not myself think it my duty to refer the case to the police" diminishes the difference between himself and the police.

Time Enough to Drink the Poison.

Though we may not be able to say which with any certainty, Mrs. Ronder is an atheist or at least a deist. Not only is she far more concerned with earthly justice than divine justice but she also intends to kill herself, thereby violating a central precept of western religions. She has a strikingly postmodern conception of the clergy as impotent while the crowd wields the true power. So we're left facing the question, what reason would a suicidal atheist have to confess? Perhaps to a.s.suage her conscience but then she might as well have told a clergyman since they traditionally keep confessions private. Or why not the more convenient answer of Mrs. Merrilow? Even if she were to report Mrs. Ronder to the police-something unlikely given her need for Mrs. Ronder's rent checks-there would be enough time to drink the poison first. Having no children or any family, it is difficult to think that any subsequent scandal would bother her.

Leonardo's death does not free her to do what she has wanted to do for nearly a decade. Rather, his death is precisely why she is now suicidal. What kept Mrs. Ronder going for the past seven or more years is the hope that perhaps she and Leonardo might be together again. In relating her story to Holmes, she confides that "at last our intimacy turned to love-deep, deep, pa.s.sionate love, such love as I had dreamed of but never hoped to feel." This is the single use of "hope" in the entire story, which is fitting since its topic is suicide. Thinking about the chance of a post-mauling relations.h.i.+p, she contrasts Leonardo's love (as she imagines it) for her with hers for him: "He might as soon have loved one of the freaks whom we carried round the country as the thing which the lion had left. But a woman's love is not so easily set aside." She goes on to tell Holmes that Leonardo died the previous month. It is only a few quick comments after that that Holmes suspects that she is contemplating suicide.

Mrs. Ronder was kept alive by the hope that she might one day be with her lover Leonardo again. She had nothing else to hope for and so when he died, so did her reason to continue living. Her situation lends credence to both philosophical positions we have explored. The Stoics and the Cartesians would note that she had patience without hope she would not be devastated by Leonardo's death. And Leibniz would point out that without the proper conception of G.o.d her hope had no real foundation, it was as frail as human mortality.

It seems unlikely that she either relinquished hope or changed her mind about G.o.d. Rather, she found a new hope, one founded on Dr. Watson. Should he recount her case, she would indeed be able to set an example of patience in an impatient world. The clue to this is her desire for a confessor who can change the past.

While no clergyman or policeman or even Sherlock Holmes himself can change the past, a writer can. Indeed, Watson tells us at the very beginning of "The Adventure of the Veiled Lodger" that "I have made a slight change of name and place, but otherwise the facts are as stated," thus signaling the true nature of Mrs. Ronder's turnabout.

Chapter 22.

Where the Most Logical Mind May Be at Fault.

Miriam Franch.e.l.la.

"I should never marry myself, lest I bias my judgement." Strange statement, Mr. Holmes, strange statement. Is it a question of misogyny? Or a playboy's excuse for avoiding stable relations.h.i.+ps? Evidently not, in Holmes's case.

But someone who talks like this is not isolated or outdated. The belief that emotion is at war with logic is still prevalent, and this raises a whole series of philosophical questions, beginning with: 'Do emotions interfere with the capacity for logical reasoning? And if so, how much?'

Dreaming of Difference.

Andrea Nye has challenged the opposition of logic and emotion. Nye describes two approaches to the world, the "masculine" and the "feminine" approach. The masculine approach considers only the formal aspects and seeks to avoid emotions. The feminine approach considers the emotional aspects. According to Nye, logic has always been a property of men, and used by them to exert power. The masculine approach steers clear of emotions so as to avoid questioning the organization of society, while the feminine approach dreams of different social structures.

Holmes seems to be a genius because of his deductive capability, and he likes to give this impression, although he also often says that he has normal faculties, common to everyone. If we credit such capability only to a few men or women, we risk what Andrea Nye warns against: logic can be used as a super-power in order to oppress other people (for instance by opposing rational westernpeople to brutish savages). Holmes himself does not do that, but this can be the ultimate conclusion of a chain of reasoning beginning with labeling him a "genius," hence superior to other people.

Some shadows begin to appear when Doyle speaks of Tonga the cannibal in The Sign of the Four. Tonga is described as like an animal, governed by pure aggressive instincts: Holmes had already drawn his revolver, and I whipped out mine at the sight of this savage, distorted creature. . . . that face was enough to give a man a sleepless night. Never have I seen features so deeply marked with all b.e.s.t.i.a.lity and cruelty. His small eyes glowed and burned with a sombre light, and his thick lips were writhed back from his teeth, which grinned and chattered at us with half animal fury. . . .

Tonga thought he had done something very clever in killing him, for when I came up by the rope I found him strutting about as proud as a peac.o.c.k. Very much surprised was he when I made at him with the rope's end and cursed him for a little blood-thirsty imp. . .

This view of some humans as little more than animals was prevalent at the time, and linked with their lack of rationality or logic. At the time of the Holmes stories, exhibitions celebrating the triumph of science and rationality were popular, as were "human zoos" in which exotic peoples were depicted in their natural primitive living conditions. We have traces of this in Tonga's story. His master recalls: "We earned a living at this time by my exhibiting poor Tonga at fairs and other such places as the black cannibal."

If logic (in any of its forms) is not considered something common to all, something human (in the sense that is comprehensible by any human being in its basic forms), then this can be dangerous. But is logic really something universal?

A first hint for our reflections comes from Carlo Cellucci who maintains that our logic is the product of evolution-it's necessary for our survival-and that a kind of logic is present also in the most simple primitive unicellular beings.

"All organisms" includes the most elementary ones, even unicellular organisms such as prokaryotes, the single cell organisms which were the first form of life on the earth in the Precambrian era. Such organisms perceive different states of the environment. The information about them is memorized in the genome and inherited, and is used by the organism to regulate its behaviour in accordance with the state of the environment. That the primary role of natural logic is to find hypotheses about the environment for the end of survival means that there is a strict connection between logic and the search of means for survival, and that, since generally all organisms seek survival, natural logic does not belong to humans only but to all organisms.

A further clue comes from Ignacio Matte Blanco, who explains that binary logic is a necessary part of life: it is necessary for distinguis.h.i.+ng ourselves from the rest of the world, and the other beings one from another. There is a kind of "basic logic" that must operate in any human being, even if we may be unaware that it is going on. Starting from this basic logic, some types of logical argument automatically appear. Furthermore, they are useful in our social life (for choosing something or for detecting liars) wherever communication by means of words occurs.

There is a difference between being a logician as a profession and using logic in everyday reasoning. Still, it's necessary to use some logic in daily life. Aside from spirits and G.o.ds, every transaction by primitive humans satisfies the logical principles of bivalence and non-contradiction. Although logic is practiced by all people, consciousness of logical laws or rules develops culturally where some people are no longer preoccupied with finding food, where the language is very sophisticated, and where important decisions are stated after many discussions and arguments. So it is not helpful to expect a person from a "primitive" tribal background to think in terms of explicit logical rules.

Even when we reason on a problem expressed in our language, we have to comprehend it in depth first, by considering the conversational context. For instance, if Granny says to her grandson "If you practice your violin, then you can go and play with your sword," she says "If A then B," but she intends "B if and only if A." When logic is applied in everyday contexts, many of the logical steps are understood rather than explicitly announced. So we shouldn't evaluate the logic of primitive people by how well they understand formal statements. Such people are fully human and naturally employ logic, though usually without any awareness of the rules of logical argument.

The same holds for many first-world people-most of the readers of this book-who are sometimes not conscious of logic even when they use it. A conscious use of logical rules becomes more and more necessary as our society becomes more and more word-based and power is exercised through a mechanism of persuasion. So it was for "democratic" Athens, so it is for our democratic countries. A person who is not used to living in such a society may not feel the necessity of developing reflections about logical arguments, because in her society most communications are short and simple.

But this doesn't mean that we "civilized people" are superior to primitive people or that we're ent.i.tled to do what we want. "Primitive" humans who actually exist and share the world with us cannot be put on a different stage of the evolutionary chain that the one on which we put ourselves, merely because we have more knowledge and a better capability of developing inferences. This would be an explanation like one based on the physical force: who is stronger is superior. An intellectual cudgel is in its essence not different from a material cudgel if it is used as a weapon of domination.

And we shouldn't forget that other cultures can offer something to us. The powder that is used in "The Adventure of the Devil's Foot" for letting relatives firstly enter into a state of lunacy and later die came from Africa, from primitive people. In this case, it was a poison, but it was however a new substance, that, in fact, Holmes-always interested in medicines that can let him have new mental experiences-tries and proposes Watson to try. "I told him how powerless European science would be to detect it" stated Dr. Sterndale: our interchanges with "primitives" are not one-way and cannot be confined to descriptions of our superiority.

Backwards Thinking.

A further question concerns the kind of logic that Holmes uses. He himself describes it as "a.n.a.lysis," a procedure that starts from data-empirical data, left by victims and murders or found out by the detective-and goes on backwards: "People who, if you told them a result, would be able to evolve from their own inner consciousness what the steps were which led up to that result. This power is what I mean when I talk of reasoning backwards or a.n.a.lytically" (A Study in Scarlet). Its procedure is presented under the label "deduction" but some have remarked that it is in fact abduction. Carlo Cellucci can help us to tackle this question.

Cellucci offers a contraposition between the axiomatic (or "synthetic") method that starts from axioms and goes on by deduction and the a.n.a.lytic method. This is the method by which, to solve a problem, one starts from the problem, finds a hypothesis that is a sufficient condition for its solution by means of a non-deductive inference (inductive, a.n.a.logical, metaphorical, metonymic, or diagrammatic), and finally checks whether the hypothesis is compatible with the existing knowledge.

If there is more than one hypothesis that can be a solution to the problem, we pick up the one which seems the "most solid." Cellucci stresses that it is a discovery method, bottom-up, where error is always possible: maybe not all possible hypotheses have been considered or the evaluation about the solidity of the hypotheses has been wrong.

In "The Adventure of the Yellow Face," Holmes believes that the anonymous person living in a cottage near his client is the first husband of his client's wife. But he later discovers that the mysterious person was instead the daughter of the client's wife and her first husband. Holmes had not even considered such a hypothesis.

Many criticisms have been raised against this method. According to philosopher and mathematician Gottfried Leibniz, this a.n.a.lytic method does not tell us how to come up with hypotheses, but only how to test hypotheses once we have thought of them. John Alan Robinson states that this a.n.a.lytic method is based on a procedure which is not rational, insofar as it requires intuition and divination.

Still, Cellucci observes, the situation is similar to that of the axiomatic method, as used in geometry. The latter defines a certain method of proof but it does not provide any indication as how to find a proof for a given proposition from given axioms. Similarly, the a.n.a.lytic method defines a certain notion of proof, but it does not provide any indication as how we could find hypotheses to solve a given problem.

This quest for the solution of a problem is an endless exercise and characterizes the method used by Plato. Many of his dialogues are not conclusive for this reason. In the Republic Plato states that the process of reasoning backwards arrives at what is no more than hypothetical. The Republic describes "the idea of a perfect Town, that-like every idea, according to Plato-can never be fully realized in this world. Only in the perfect City can the principle of everything be reached. Hence, in this imperfect world the search for hypotheses is a potentially infinite process" (Cellucci). And this long tradition of a.n.a.lysis is the method which Sherlock Holmes referred to.

We can observe that the difference between the a.n.a.lytic process executed inside an investigative context and within a theoretical context is that in the first case the quest has an end: when we caught the murderer (and know the reasons for the killing), we are satisfied. We do not need-for instance-to find the reasons why she had such and such feelings that led her to kill. When we establish that Mr. X had revenge reasons for a murder, it's enough. We don't ask why he could not forgive the victim's past actions. We can stop there.

According to what we have just specified, we should better express Holmes's being a genius in terms of capability of finding the right path upwards. We can agree with this opinion of Holmes's methods: Holmes's success at his brand of "deduction" is well described as a mastery of both a huge body of particular knowledge of things like footprints, cigar ashes, and poisons, which he uses to make relatively simple deductive inferences, and the fine art of ordering and weighing different competing explanations of a body of evidence. Holmes is also particularly good at gathering evidence by observation, as well locating and tracking the movements of criminals through the streets of London and environs (in order to produce more evidence)-skills that have little to do with deduction per se, but everything to do with providing the premises for particular Holmesian inferences. (www.wordiq.com/definition/Sherlock_Holmes) Still, it should be stressed that mastering the paths upwards requires also mastering the paths downwards. In other words, the "right" hypothesis for a certain conclusion must be one that can be shown to lead to that conclusion. So, declaring that a hypothesis is right presupposes in any case the verification that that hypothesis leads to that conclusion, verification that consists of a deduction.

Emotional Rescue.

At the same time that Andrea Nye was writing her book challenging our ways of considering logic, investigations of the psychology of reasoning looked at why we so often make errors. The role of emotions has been re-examined, and the results are that the role of emotions is at least ambivalent: sometimes emotions drive us away from the right path, but sometimes they help.

For instance, the Wason (Wason, not Watson!) test is one of the standard examples of how most people don't think logically. In the most talked-about version of this test, the experimenter places four cards on a table which have a letter or a number visible to the partic.i.p.ant ("A", "D", "4", "7"). The partic.i.p.ants are told that each card has a number on one side and a letter on the other side.

The problem for the subject is to choose which cards to turn over to determine whether the following rule is true or false about the four cards: "If a card has a vowel on one side, then it has an even number on the other side."

The correct answer would be "A" and "7" (and only "A" and "7"), because the only situations that do not obey the above rule occur when a vowel on one side is accompanied by an odd number on the other side. So, the only relevant evidence is whether "A" has an even number on the other side and whether "7" has a consonant on the other side. Most people get this wrong.

However, that's not the end of the matter, because it was later found that the percentage of subjects getting this problem right goes up dramatically if it is cast in terms of a real problem from everyday life, especially one involving social obligations.

For instance the same logical principle can be presented as follows. There are four boys at summer camp, respectively aged 14 and 21, drinking beer and drinking water; the rule is "If a person is drinking beer then he must be over 18." In this case, if we put the question "Which of them should be checked out to establish if the rule is respected," then most people easily get the correct answer. It now seems obvious that the two examples to check up on are the boy aged fourteen and the boy drinking beer. Apparently the risk of being punished or deceived stimulates our capability for thinking logically. So it seems that some emotional involvement may sometimes help us to reason correctly.

Still, there are also reasons in favour of a strict symbolicformal expression of reasoning. Gottlob Frege, who tried to design a new and purely logical language, understood that in everyday life, logic is all bound up with feelings and images, but that it can be helpful to identify the purely logical by stripping away these non-logical a.s.sociations. According to Frege, "language does not simply express thoughts; it also imparts a certain tone or colouring to them. And this can be different even where the thought is the same." "In human beings it is natural for thinking to be intermingled with having images and feeling. Logic has the task of isolating what is logical . . . so that we should consciously distinguish the logical from what is attached to it in the way of ideas and feelings."

This Way Lies Madness.

Logicomix by Apostolos Doxiadis and Christos Papandropoulos sheds some light on this desire of avoiding feelings inside logic. The authors consider the biographies of important logicians like Frege, Bertrand Russell, Ludwig Wittgenstein, and Kurt G.o.del, claiming a link between logic and madness: some people devote their life to logic because they are incapable of managing their emotions. They're afraid of becoming mad, use logic as a way to live in a solid and sure world, but then their inability to manage their emotions results in the very thing they're afraid of: their madness-or that of their relatives. Russell's character says of Wittgenstein: "Like me, he constantly a.n.a.lyzed everything, a habit that annihilates emotions" and then the authors remark: "Russell's childhood had given him good reasons for annihilating emotions. Character, uncertainty, neurosis led him to logic" (p. 236). We're also informed that Russell's son suffered from schizophrenia, and that the same was true for Hilbert's son. The authors speculate that the fear of emotions which impels some people to study logic may make them bad parents.

Holmes has often been described as neurotic. Some diagnose Holmes as suffering from bipolar disorder. This can be inferred from the fact that he alternates between days or weeks of listless la.s.situde and periods of intense engagement with a challenging case or with his hobby, experimental chemistry. Some websites have instead diagnosed Holmes with Asperger syndrome, a light form of autism .

Uta Frith, in her essay on "Autism: Explaining the Enigma," identifies the clues of Holmes's Asperger syndrome in Holmes's oddness, his socially detached mind, and his circ.u.mscribed but deep interests (as testified by his little monograph on the ashes of 140 different varieties of pipe, cigar and cigarette tobacco), that Frith describes as still vital ingredients "in all creations in art or science". Both the novel and film The Seven-Percent Solution give a psychoa.n.a.lytic explanation for Holmes's behavior.

Logic can be a harbor for people escaping from emotions. In this case it represents a false harbor, since psychological problems should be faced and not simply put aside; otherwise they come back to bite us somewhere else. Strong emotions can also motivate us to concentrate better and become more logical.

Sherlock Holmes declares that he has to refrain from loving to keep his mind clear, but perhaps if he were open to love, he might even find his powers of a.n.a.lysis and deduction enhanced.

Chapter 23.

What Mycroft Knows that Sherlock Doesn't.

Andrew Terjesen.

Sherlock Holmes is the master of the science of deduction, a consulting detective with no equal. Everyone seems to think so. But is he really?

By Sherlock's own admission, his older brother is the true master at solving puzzles and problems. He tells Watson, "When I say, therefore, that Mycroft has better powers of observation than I, you may take it that I am speaking the exact and literal truth" ("The Adventure of the Greek Interpreter"). Sherlock makes it very clear that he considers Mycroft to be his superior in both observation and deduction.

We see this superiority of Mycroft on display in his first appearance. At the Diogenes Club, Mycroft and Sherlock engage in a series of deductions very reminiscent of Sherlock's skillful conclusion in A Study in Scarlet that Watson was recently discharged from Afghanistan. Sherlock and Mycroft engage in a series of deductions about someone who has recently served in India. In this instance, Mycroft picks up on a particular detail (that the man had more than one child) that Sherlock seems to have missed.

But what is it that makes Mycroft better than Sherlock?

Is it that Mycroft has a photographic memory that enables him to function as a living computer for the British government? Possibly. After all, Watson tells us the limits of Sherlock's knowledge, and there seems to be a lot he doesn't know about. If that were the issue though, it's unlikely that Sherlock would have called Mycroft better at observation and deduction.

Is it simply that Mycroft has had seven more years of practice than Sherlock? Again, that might be a viable explanation, but I imagine that Sherlock's pride and his dogged adherence to the facts would have caused him to mention that simple difference.

Instead, Mycroft's superior skills arise out of the one major difference between the brothers that Sherlock remarks on when he first mentions his brother to Watson: Mycroft has no interest in detective work.

Mycroft's Unique Insight.

It's tempting to think that Mycroft's lack of interest is a result of laziness and not the product of some special insight into "the science of deduction." In both of the major appearances of Mycroft in the canon, Sherlock makes a point of telling Watson that his brother is lacking in ambition and energy.

Certainly the reason Mycroft gives for pa.s.sing a case on to Holmes seems to back up this view. When he asks Sherlock to look into the case of stolen submarine plans, he is emphatic that he won't take care of it himself (even though it is a matter of national security). As he explains to Sherlock, "Give me your details, and from an armchair I will return you an excellent expert opinion. But to run here and run there, to cross-question railway guards, and lie on my face with a lens to my eye-it is not my metier" ("The Adventure of the Bruce-Partington Plans"). However, a lazy person would not bear the burden of running the British government (as Sherlock mentions that his brother is the government at times).

Of course, this could be a very specific form of laziness, like Sherlock's own aversion to spending time learning about philosophy or astronomy. As Sherlock points out, his brother will not even go out of his way to verify his own solutions, and would rather be considered wrong than take the trouble to prove himself right. Again and again I have taken a problem to him, and have received an explanation which has afterwards proved to be the correct one. ("The Greek Interpreter") Mycroft is especially useless as a consulting detective because he will not take the time to work out the "practical points" that must be worked out before the case can be put before a jury. But it seems to me that it's quite likely that Mycroft sees no point in such endeavors because he appreciates the "Problem of Induction" in a way that his brother does not.

Lock and Key.

"Induction" is the name logicians prefer to give to what Sherlock calls "The Science of Deduction." In everyday speech, we tend not to distinguish between induction and deduction and often use the terms interchangeably. Logicians think it is very important to differentiate between these two types of reasoning because each has its own problems that must be considered when evaluating an argument.

Deduction, as used by logicians, refers only to arguments that are constructed in such a way that their premises guarantee the truth of the conclusion. A cla.s.sic example of a deductive argument is the process of elimination, in which one eliminates every other possibility and whatever remains (no matter how improbable) must be the truth. Holmes gives an example of this when investigating the theft of the Bruce-Partington plans as he reasons about how the suspect, Cadogan West, could have gotten the plans from the safe.

Holmes considers three possibilities: West used the clerk's keys, West used Sir James' keys or West had a copy made of one of those sets of keys. Holmes eliminates the clerk because he had only a key to the safe, he lacked the keys needed to open the building and the office. Sir James has all three keys, but they are always with Sir James who was in London at the time of the theft. The only possibility remaining is that West had a copy made and that must be what happened given the original premises of the argument. If there are only three possibilities and two are impossible then the one that is left must be what happened.

While most of Holmes' deductions end with a real bit of deductive reasoning, like this process of elimination, they almost always rely on quite a bit of inductive reasoning to establish the premises. Unlike the conclusions of a deductive argument, the conclusion of an inductive argument can only be known to be probably true. The conclusion of an inductive argument is never guaranteed to be true, even if all the premises supplied are true.

In the Bruce-Partington example, Holmes's process of elimination depends on there being only three possibilities. Holmes relies on inductive reasoning (in this case a bit of observation as to who had the keys and an inference from experience that keys can be copied) to establish these possibilities. When reasoning inductively there is always the possibility that we have missed some important bit of observation or that the experiences one is making inferences from are incomplete. In this case, Holmes had not considered the possibility that Sir James's brother Colonel Valentine had made copies of Sir James's keys so that he could steal the plans and sell them in order to pay off his debts.

This is the nature of induction, but it is not "The Problem of Induction" with a capital "P." Sherlock is very aware of the limits of reasoning from experience and observation. As he tells Watson at one point, "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" ("A Scandal in Bohemia").

Holmes knows full well that insufficient data can lead to wrong-headed conclusions and so he usually plays things close to the chest until he has a critical ma.s.s of information. Scientists often rely on inductive reasoning in their experiments, so the scientific method strives to make sure that the sample size is sufficient and to test hypotheses. Holmes does the same thing before wrapping up a case. Although he suspected that West was not the culprit, he had to draw out the real thief and even he was surprised when it was Colonel Valentine. However, a simple awareness of the limits of probability and the possibility of missing an important clue are not the real problems of induction.

Billiard b.a.l.l.s that Don't Move.

The philosopher David Hume is among the first to clearly identify what has become known as the Problem of Induction. In his Enquiry Concerning Human Understanding, Hume lays out the Problem as follows: When I see, for instance, a Billiard-ball moving in a straight line towards another; even suppose motion in the second ball should by accident be suggested to me, as the result of their contact or impulse; may I not conceive, that a hundred different events might as well follow from that cause? May not both these b.a.l.l.s remain at absolute rest? May not the first ball return in a straight line, or leap off from the second in any line or direction? All these suppositions are consistent and conceivable. Why then should we give the preference to one, which is no more consistent or conceivable than the rest? All our reasonings a priori will never be able to show us any foundation for this preference. (Section IV, Part 1) Hume's point is that when we see someone hitting one billiard ball so that it rolls straight towards another, we antic.i.p.ate that the motion of the first billiard ball will be transferred to the second when they collide. After the collision, the first ball will stop and the second ball will move in the direction that the original ball was traveling. We would be astounded if the second billiard ball was not set into motion after the first had collided with it. If it did happen, we would begin to look for a logical explanation. For example, did the original billiard ball run out of momentum before getting to the second ball and only appeared to make contact? Or was it the case that the second billiard ball had been glued to the table or nailed down?

We look for intervening cause because we think that there is a fixed rule underlying our observations. The Problem of Induction is that we have no good reason for thinking that such a rule exists. If we were to ask someone watching a billiard game why they feel justified in thinking that the ball will go into a particular pocket, their answer would probably be: because that is where it has gone in the past. But we must then ask, what makes you so sure that the future will follow the same rules as the past? The answer cannot be that it will do so because it has done so in the past. That would be circular reasoning. We would be using our inductive reasoning to prove that our inductive reasoning always works. That would be like saying that someone is honest because they say they would never lie.

When Hume says that no "reasonings a priori" will show us that induction works, he is pointing out that deduction can't cut it. A priori reasoning is the reasoning we do without having to have any experience of the world. For example, I can understand 2 + 2 = 4 even if I have never seen 2 and 2 put together in the world. That is because I understand the rules of arithmetic. Those rules are such that if I am given a certain set of values then a certain result will necessarily follow. 2 and 2 do not equal 5. In order for the rules of arithmetic to be that certain, they cannot depend on any facts about the world that we need to observe before we add 2 and 2. There are no comparable rules that I am familiar with that govern billiard b.a.l.l.s. We need to observe things like the slope of the table, the weight of the b.a.l.l.s, and so on. Even with all that information, the geometry that many pool sharks rely upon will not predict with one hundred percent accuracy where the ball will go after it is. .h.i.t.

A popular argument used in defense of induction is that we can observe regular patterns and therefore we have some sense of the underlying rules. In all my life, I have never seen a billiard ball go unmoved upon contact. The preponderance of evidence seems to go against a billiard ball remaining unmoved. The problem with that kind of argument is revealed by a variation on the thought experiment concocted by the philosopher Nelson Goodman in his book Fact, Fiction, and Forecast. Goodman asks us to imagine a property called "grue" which refers to an object that looks green if it is first observed before a certain date (let's say 2100) and it will look blue if it is first observed after that date. In 2012, you find an emerald that looks green. How do you know if it is green or grue? Green and grue have the same regular behavior up until a certain point. Grue may seem like an arbitrary property, but is it any different from a radioactive element turning into lead or a b.u.t.terfly into a caterpillar? If you're dealing with a pattern that is so complex that we can't observe it in full, how can you differentiate between two possible explanations of that pattern? The Problem of Induction is that there is no definitive reason to prefer one explanation over the other as all the data you collect (until 2100) will support both explanations. After 2100, you'll know that when you find a green emerald it will really be green, but when you find a blue emerald you won't be able to tell if it is blue or grue.

Superficial Tricks.

Conan Doyle seemed to be pretty well aware of the Problem of Induction. In a short parody he wrote ent.i.tled "How Watson Learned the Trick," Watson tried to turn the table on Holmes. Watson inducted that Holmes was preoccupied because he had not shaved that morning and that he had begun to engage in stock trading because he made a loud exclamation of interest when looking at the financial page.

It turns out that Watson is totally off the mark. Holmes hadn't shaved because he had sent his razor to be sharpened, and Holmes was showing interest in the cricket scores which are on the page beside the financial news. Holmes is bemused by Watson's failure to learn his "superficial trick," but when it comes down to it, there was nothing wrong with Watson's failed induction. His method was indistinguishable from Holmes's. The fact that his conclusion was wrong is not an indictment of his method. After all, scientists arrive at wrong conclusions all the time because induction is not guaranteed to lead you to the right conclusion. This doesn't mean scientists should abandon using induction.

One well-known attempt to defend the scientific method was proposed by the philosopher Karl Popper. Popper argued that scientists don't use induction to confirm things; instead they make hypotheses based on experience and test their predictions. If their prediction fails, then the hypothesis is thrown out. If the prediction is successful then that doesn't make the hypothesis true, it merely shows that it is still a viable option. Popper's theory is known as falsificationism because it holds that the main task for scientists is to try and falsify theories.

What Popper has done is respond to the Problem of Induction by claiming that science isn't based in induction. So, he hasn't dealt with the real Problem. In fact, the Problem of Induction haunts falsificationism because there is usually more than one way to understand a failed experiment. It could show that the hypothesis is false or it could show that our means for testing it was based on faulty a.s.sumptions. Once again, we can't easily decide between two explanations for the results we observed.