What I've Been Reading

A Few Lessons from Sherlock Holmes by Peter Bevelin. Anything Bevelin writes oozes with wisdom - A must read!

But only what is useful - it can be dangerous to know too much:

• His ignorance was as remarkable as his knowledge... He said that he would acquire no knowledge which did not bear upon his object. Therefore all the knowledge which he possessed was such as would be useful to him. (Dr. Watson; A Study in Scarlet)
• Now the skillful workman is very careful indeed as to what he takes into his brain-attic. He will have nothing but the tools which may help him in doing his work, but of these he has a large assortment, and all in the most perfect order. It is a mistake to think that that little room has elastic walls and can distend to any extent. Depend upon it there comes a time when for every addition of knowledge you forget something that you knew before. It is of the highest importance, therefore, not to have useless facts elbowing out the useful ones. (Holmes; A Study in Scarlet)

It is useful to know something about human nature and what motivates people:

• There are some trees, Watson, which grow to a certain height, and then suddenly develop some unsightly eccentricity. You will see it often in humans. (Holmes; The Empty House)

Ask: What is in their interest to do?:

• He remarks that, while the individual man is an insoluble puzzle, in the aggregate he becomes a mathematical certainty. You can, for example, never foretell what any one man will do, but you can say with precision what an average number will be up to. Individuals vary, but percentages remain constant. So says the statistician. (Holmes; The Sign of the Four)

But knowledge doesn’t automatically make us wise - the most learned are not the wisest:

• Judgment can do without knowledge but not knowledge without judgment. (Montaigne)

And Learning Never Stops:

• Like all other arts, the Science of Deduction and Analysis is one which can only be acquired by long and patient study, nor is life long enough to allow any mortal to attain the highest possible perfection in it. (Holmes; A Study in Scarlet) 
• Education never ends, Watson. It is a series of lessons with the greatest for the last. (Holmes; The Red Circle)

On Solving a Case - Observation and Inference:

• Cultivate absolute accuracy in observation, and truthfulness in report. (Joseph Bell; Dr Joe Bell) 
• It is very evident that in this we have two main processes to bear in mind and keep strictly distinct, first, the collection of the observations, and second, the inferences to be drawn from them. (Thomas McCrae; The Method of Zadig)
• Observation is a matter of patience, training and thoroughness, in all of which a man may improve himself, but the use which he makes of his observations is partly a matter of his mental equipment. True he can train his powers of thought and judgment to some extent, but, we vary greatly in the quality of our cerebral cells, and the saying of the father of medicine, “Experience is fallacious and judgment difficult,” is always true. To observe correctly and decide wrongly is sure to happen to the best of us, but to observe carelessly happens only when we permit it. (Thomas McCrae; The Method of Zadig)

Never jump to conclusions and try to collect facts as open-minded as possible:

• We approached the case... with an absolutely blank mind, which is always an advantage. We had formed no theories. We were there simply to observe and to draw inferences from our observations. (Holmes; The Cardboard Box)

Observation - Start with collecting facts and follow them where they lead:

• More is missed by not looking than not knowing. (Thomas McCrae; Medical School Axiom)
• For one mistake made for not knowing, ten mistakes are made for not looking. (James Alexander Lindsay)

What are the facts? Holmes first gathered enough evidence - both positive and negative - that was relevant to his problem:

• You’re like a surgeon who wants every symptom before he can give his diagnosis.  “Exactly. That expresses it.” (Holmes; Thor Bridge)
• It is usually wiser to tell the truth. (Holmes; The Veiled Lodger)

Make sure “facts” are facts - Is it really so? Is this really true? Did this really happen? I realize that if you ask people to:

• I realize if you ask people to account for “facts”, they usually spend more time finding reasons for them than finding out whether they are true... They skip over the facts but carefully deduce inferences. They normally begin thus: “How does this come about?” But does it do so? That is what they ought to be asking. (Montaigne)

Deception has many faces:

• If falsehood, like truth, had only one face, we would be in better shape. For we would take as certain the opposite of what the liar said. But the reverse of truth has a hundred thousand shapes and a limitless field. (Montaigne)
• Observe that rule laid down by Chilo, Nothing to excess... Not to believe too rashly: not to disbelieve too easily. (Montaigne)

Why may they be lying or deceive us? What is out of the ordinary?:

• We must look for consistency. Where there is a want of it we must suspect deception. (Holmes; Thor Bridge)

There may be many theories that fit the facts:

• Circumstantial evidence is a very tricky thing... It may seem to point very straight to one thing, but if you shift your own point of view a little, you may find it pointing in an equally uncompromising manner to something entirely different. (Holmes; The Boscombe Valley Mystery)

More information isn’t necessarily better information but it may falsely increase our confidence - What is not worth knowing is not worth knowing:

• A wise man sees as much as he ought, not as much as he can. (Montaigne)

Get down to the root of the matter:

• I fear, sir... that, interesting and indeed essential as these details are, my inquiries must go more to the root of things. (Holmes; The Second Stain)
• “But what is at the root of it?”  “Ah, yes, Watson -- severely practical, as usual! What is at the root of it all.” (Holmes; The Red Circle)

Know where to look:

• The world is full of obvious things which nobody by any chance ever observes. (Holmes; The Hound of the Baskervilles)

The eye sees only what it is trained to see:

• In the last analysis, we see only what we are ready to see, what we have been taught to see. We eliminate and ignore everything that is not a part of our prejudices. (Jean-Martin Charcot)

We need to both observe the big picture - forest - and the details - trees - Sometimes the trivial or the most immaterial aspect of a case may be the most important but we need to learn how to separate between trifles that matter and those that don’t:

• It has long been an axiom of mine that the little things are infinitely the most important. (Holmes; A Case of Identity) 
• The great majority of people, of incidents, and of cases resemble each other in the main and larger features... Most men have... a head, two arms, a nose, a mouth, and a certain number of teeth. It is the little differences, themselves trifles, such as the droop of an eyelid, or what not, which differentiates man. (Joseph Bell; Dr. Joe Bell)

Sometimes we overlook that which is most obvious:

• In searching for the obscure, do not overlook the obvious. (James Alexander Lindsay)

Deduction - What inferences can we draw from our observations and facts?:

• But we hold several threads in our hands, and the odds are that one or other of them guides us to the truth. We may waste time in following the wrong one, but sooner or later we must come upon the right. (Holmes; The Hound of the Baskervilles)

What normally happens in similar situations? Why should this be any different?:

• Common diseases cause uncommon symptoms more often than uncommon diseases cause common symptoms. (Medical maxim)

What doesn’t matter? What can’t happen? What can’t it be? What can’t be done?:

• That process... starts upon the supposition that when you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth. It may well be that several explanations remain, in which case one tries test after test until one or other of them has a convincing amount of support. (Holmes; The Blanched Soldier)

Test Our Theory- if it disagrees with the facts it is wrong:

• Physicians often pride themselves on curing all their patients with a remedy that they use. But the first thing to ask them is whether they have tried doing nothing, i.e., not treating other patients; for how can they otherwise know whether the remedy or nature cured them? (Claude Bernard)
• To choose a road, to stop habitually and to ask whether you have not gone astray, that is the true method. (Louis Pasteur)

Check for other possible explanations - What else can explain this?:

• We all learn by experience, and your lesson this time is that you should never lose sight of the alternative. (Holmes; Black Peter)

Patience - Take time to think things over:

• I knew that seclusion and solitude were very necessary for my friend in those hours of intense mental concentration during which he weighed every particle of evidence, constructed alternative theories, balanced one against the other, and made up his mind as to which points were essential and which immaterial. (Dr. Watson; The Hound of the Baskervilles)

Get a different view - talk it over with someone else:

• Nothing clears up a case so much as stating it to another person, and I can hardly expect your co-operation if I do not show you the position from which we start. (Holmes; Silver Blaze)
• I was a whetstone for his mind. I stimulated him. He liked to think aloud in my presence. His remarks could hardly be said to be made to me -- many of them would have been as appropriately addressed to his bedstead -- but none the less, having formed the habit, it had become in some way helpful that I should register and interject. If I irritated him by a certain methodical slowness in my mentality, that irritation served only to make his own flame-like intuitions and impressions flash up the more vividly and swiftly. Such was my humble role in our alliance. (Dr. Watson; The Creeping Man)

A rule is only a rule if it’s always true:

• I never make exceptions. An exception disproves the rule. (Holmes; The Sign of the Four)

Watch out for overconfidence:

• My case is, as I have told you, almost complete; but we must not err on the side of overconfidence. Simple as the case seems now, there may be something deeper underlying it. (Holmes; The Sign of the Four)

Update our beliefs in light of new information:

• I have devised seven separate explanations, each of which would cover the facts as far as we know them. But which of these is correct can only be determined by the fresh information which we shall no doubt find waiting for us.

Learn from your mistakes - and learn the general lessons:

• If it should ever strike you that I am getting a little over-confident in my powers, or giving less pains to a case than it deserves, kindly whisper “Norbury” in my ear, and I shall be infinitely obliged to you. (Holmes; The Yellow Face)
• Should you care to add the case to your annals, my dear Watson... it can only be as an example of that temporary eclipse to which even the best-balanced mind may be exposed. Such slips are common to all mortals, and the greatest is he who can recognize and repair them. (Holmes; The Disappearance of Lady Frances Carfax)
• I confess that I have been as blind as a mole, but it is better to learn wisdom late than never to learn it at all. (Holmes; The Man with the Twisted Lip)

It is easy to be wise after the event, but very difficult to be wiser:

• A patient dies in whom you have made a diagnosis of typhoid fever, and at autopsy military tuberculosis is found. You are wise after the event but the laboratory Diener or a first year student is just as wise as you. To be wiser, or in other words to lessen the chance of your making the same mistake again, is quite another matter. You will certainly be no wiser if you have persuaded yourself that after all you did think it was military tuberculosis. For one’s own training it is better to make an incorrect diagnosis than none at all-if you call yourself to account afterwards. (Thomas McCrae; The Method of Zadig)

A lot of misery comes from what we allow ourselves to get dragged into. Avoid danger - we shouldn’t expect to survive when we enter tough seas:

• It was a singular spot... that old death trap of sailing vessels, with its fringe of black cliffs and surge swept reefs on which innumerable seamen have met their end. (Dr. Watson; The Devil’s Foot)