I've never read a Sherlock Holmes novel. I would wager that a lot of millennials can say the same. I did however recently pick up a short book from Peter Bevelin titled A Few Lessons from Sherlock Holmes. Needless to say, it got my attention.
Nassim Taleb called Peter Bevelin "one of the wisest people on the planet" and after only an hour or so of reading, I could see why. How one packs so many powerful ideas in so few pages, I'm not sure I'll ever understand. For now, I can only appreciate it. These were the ideas and takeaways that stuck with me most.
Learn Across a Wide Range of Disciplines
All our ideas are combinations of other ideas. If you want to have more ideas, collect more ideas in general. If you want to have more interesting ideas, make sure those ideas you are collecting span multiple disciplines. Charlie Munger often refers to this concept when talking about his latticework of mental models.
Having a breadth of diverse views to pull from leads to the interplay of ideas and oblique use cases that would have otherwise been missed.
Collect Only Useful Ideas
Most topics aren't worth having an opinion about. Let alone saving for later. Sherlock Holmes understood that ignorance is just as important as knowledge.
It's silly to think that we have infinite room for mental connections. You must unload the mind of things that aren't useful to create room for ideas that will be.
Practice Teaches Us What to Look For
Most important endeavors can't be simulated beforehand. There are too many variables shifting around far too often. Because of this, predicting what will happen in the future is near impossible.
So, what's the point of practice? Practice is still useful, even if it's not a 1:1 representation of the thing itself. Besides, practice isn't about the action. It's about learning where to look and what to look for.
Keep Observation and Inference Separate
There are two main processes that we go through when presented with a problem: observation and inference. It's important to keep these separate, as difficult as it may be.
You want to be as objective as possible in your fact collection. To do that, you can't jump to conclusions. Humans can't help but try and justify and defend their theories. Once you start generating ideas, there's no going back.
Collect Facts With an Open Mind
Leave any preconceptions and prejudices you have at the door. Approach the problem with a blank mind. This is your greatest advantage.
You are there to observe and to draw inferences from your observations. Otherwise, you will find yourself twisting your data around to fit your theories. Instead, generate theories that suit your facts.
Quality Matters More Than Quantity
Don't miss the forest for the trees. It's not the amount of information that counts, but how relevant it is. It's easy to convince yourself that you have things under control with pages upon pages of notes jotted down. But how much of that information passes the quality test?
To check yourself, separate out the important from unimportant facts. This not only gives you clarity over what you know and what you don't, but it also helps you from becoming overconfident.
There Are Many Theories That Fit the Facts
If history tells us anything, it's that there is no combination of events for which we can't come up with an explanation. We are excellent at justifying things.
I've come to learn few things in life are certain. It's all one big probabilistic game. Keep this in mind when you approach analysis. Even something as simple as asking yourself, "Are these results real?" can be helpful.
Acknowledge that there is more than one answer and whatever conclusion you come to has significant error bars. And that's okay.
The Eye Only Sees What It Is Trained to See
We only see what we have been taught to see. It's in our nature to eliminate and ignore everything that is not part of our prejudices.
The idea of Black Swan Events is related to this. We don't see these extreme events coming because they don't fit our prior mental model of the world. When they happen, we look for somewhere to point the finger. In reality, we were wrong, not the world. We just weren't trained to see it.
Systematically Eliminate Possibilities
Cultivate the habit of orderly examination of theories. Just like you separated useful observations from the irrelevant, you should eliminate low probability conclusions.
Start by stating all possibilities and by exclusion, narrow them down to the one or two most likely. This level of focus will enable you to avoid bias that you might have fallen for otherwise.
Take Time to Think Things Through
When you are spinning or stuck on a particular problem, try to create alone time to think deeply. Sherlock Holmes once described a tricky case as a "three-pipe problem" because he wanted to be alone and think for an hour or so.
You may have to go for days or even weeks turning it over, rearranging facts, looking at every point of view. The conclusion will either become clear or you have to stand up and realize that the data is insufficient. The latter is one of the hardest things to do.
Know Your Limitations
The best learnings are those that teach us where our knowledge leaves off and ignorance begins. Knowing your limitations is a superpower that pays dividends everywhere else.
If you know your limitations, you can more easily improve your thinking. You begin to notices mistakes and correct them. This iterative mindset is key. It's easy to be wise after the event, but difficult to be wiser in general.
That's all she wrote. This was one of my favorite reads in recent memory, and you can go through it in only an hour or so. To summarize:
- Learn across a wide range of disciplines
- Collect only useful ideas
- Practice teaches us what to look for
- Keep observation and inference separate
- Collect facts with an open mind
- Quality matters more than quantity
- There are many theories that fit the facts
- The eye only sees what it is trained to see
- Systematically eliminate possibilities
- Take time to think things through
- Know your limitations
If you enjoyed this then I recommend diving into some of Farnham Street's blog posts on mental models. There's some good stuff there. If you want to browse more book summaries, head over to the blog and look for posts under the Reading topic.