A Few Lessons From Sherlock Holmes by Peter Bevelin

Summary
  1. Bevelin takes quotes and examples from Sherlock Holmes as examples of several tools and techniques to improve thinking and decision making
Key Takeaways
  1. Observation and inference
    1. See things for what they are and report them truthfully
    2. Beware of first impressions – appearances can be deceiving
    3. More is missed by not looking than not knowing
    4. It is not the amount of information that counts by the relevant one
    5. Sometimes it helps to shift perspective
    6. The value of experience is not in seeing much but seeing wisely
    7. “By doing it many times over till it is done perfectly – for it is worth doing.”
    8. Checklist routines for critical factors to help
    9. Look as diligently for what is missing for what is there
  2. Deduction
    1. Reasoning backwards, working back from observations/effects to causes
    2. Use the simplest means first
  3. Analogies
    1. You cannot judge the relevance of an isolated fact. Experience has taught me, and must have taught you, that the most trivial, commonplace and seemingly irrelevant facts have a way of suddenly assuming a crucial importance by connecting, explaining or filling in the detail of later discoveries
    2. 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
  4. Test your theory
    1. If it disagrees with the facts, it is wrong
    2. There is nothing more deceptive than an obvious fact
  5. Patience
    1. Distance gives perspective – sometimes we need to remove ourselves from the problem and get a fresh perspective
  6. Put self in other’s shoes
    1. If we could see the world the way others see it, we easier understand why they do what they do
    2. Don’t make the world fit your tools and use the right tool for the job
  7. Criticize self
    1. Have you tried to find evidence against what you believe? Why might we be wrong? What have we overlooked? What (new) information or evidence is needed to make us change our mind?
    2. When we meet a fact which contradicts a prevailing theory, we must accept the fact and abandon the theory, even when the theory is supported by great names and generally accepted
  8. Learn from mistakes
    1. Update your beliefs in light of new information
    2. For one’s own training it is better to make an incorrect diagnosis than none at all – if you call yourself to account afterwards
  9. Know your limits
    1. Don’t think about how to get things done, instead ask whether they’re worth doing in the first place
    2. A lot of misery comes from what we allow ourselves to get dragged into
What I got out of it
  1. Really good, short read on some key characteristics necessary for deep thinking and better decision making