

This article is an excerpt from the Shortform book guide to "The Great Mental Models Volume 3" by Rhiannon Beaubien and Rosie Leizrowice. Shortform has the world's best summaries and analyses of books you should be reading.
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How much of life is random? What can be gained by accepting that randomness?
You could understand anything in the world by learning a finite set of rules and patterns that apply to all aspects of life. That’s the premise of The Great Mental Models series of books from Farnham Street (FS), a website dedicated to timeless knowledge and insightful ideas. The Great Mental Models Volume 3 argues that we can benefit by accepting that most of life is random. The benefits include making better decisions, making fewer prediction errors, and enjoying more creativity.
Keep reading to learn more about what can be gained by understanding the randomness of life.
The Randomness of Life
The model of randomness can help prevent thinking errors by reminding you that sometimes there isn’t a pattern to be found. Authors Rhiannon Beaubien and Rosie Leizrowice argue that most of what happens does so by chance. They say that we don’t realize this because humans constantly try to connect events into stories with clear cause-effect relationships.
(Shortform note: This is known as the narrative fallacy. In Thinking, Fast and Slow, Daniel Kahneman explains that the narrative fallacy occurs because we tend to look for patterns and causal explanations even where none exist. For example, he says that during the German bombing of London during World War II, people suspected that there were German spies housed in unbombed areas of the city—so much was bombed that people assumed the untouched areas must have been left alone for a reason. In fact, Kahneman says, the distribution of bombed and unbombed areas was totally random.)
The idea that the universe is mostly random might seem scary at first, but Beaubien and Leizrowice point out that recognizing the randomness of life has numerous benefits, starting with better decision-making. For example, if you keep in mind that your observations are subject to randomness, you’ll realize that it’s important to have a sufficient number of observations before you draw any conclusions. In the example of wealth distribution above, if you consider only two of the 10 people in the room, you’ll have a totally inaccurate picture of the situation—you might conclude either that everyone in the room makes $30,000 or that half of them make $30,000 and half of them make $2,000,000.
(Shortform note: In Thinking, Fast and Slow, Kahneman argues that this is another way that narrative thinking leads to mistakes: Because we’re quick to make causal links between facts, we can forget to make sure we have a big enough sample to support the conclusion we’ve drawn.)
Understanding randomness also helps you avoid making faulty predictions. The authors point out that a fair coin is equally likely to land on heads or tails on any given flip. That means that even if it comes up heads 10 times in a row, it still has a 50% chance of coming up heads the next time. It can be easy to forget that because we intuitively realize that the odds of flipping heads 10 times in a row are extremely low—1 in 1,024 to be exact. Therefore, when we see 10 heads in a row, we might think the coin is due to come up tails. This mistake is called the gambler’s fallacy—and casinos make big profits off it all the time.

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Here's what you'll find in our full The Great Mental Models Volume 3 summary :
- How to understand anything in the world by learning a finite set of rules and patterns
- A look at how humans are driven by algorithms
- Why you shouldn't be fooled by randomness