Great Mental Models Vol 1 - Shane Parrish

1. Why do we need mental models?

   1. Imagine a group of blind people approaching an elephant. None of them are aware of its shape or form and gather around it to touch it in different places. One feels the trunk, and thinks it's a snake. Another feels the leg, and thinks it's a tree-trunk. Another feels its side, and thinks it's a wall etc.

   2. It's all about perspectives. It's like our brain has 400-horsepower potential, but we only output 50 at a time. To achieve our full potential, we need to develop a latticework of mental models to use together.

2. Circle of competence

   1. Over 200 people have died climbing Mount Everest. It's one of the most difficult treks in the world. On average, anyone who successfully climbed the mountain only did it once. But Sherpas (locals) club it many times in their lifetime. It's part of their day job. They don't die as much as they know what they understand and also know what they don't know. It helps them make decisions quickly and accurately. This is their circle of competence.

   2. How to operate outside your circle of competence

      1. Learn at least the basics of the realm, whilst acknowledging that you are a stranger.

      2. Talk to someone whose circle of competence in that area is strong. You need to put in some time to research and ask good questions, so they're not just giving you a fish, but teaching you fishing.

      3. Use your broader understanding of mental models of the world to augment your limited understanding of the new area. These will help identify foundational concepts.

3. Inversion

   1. Approaching a situation from the opposite end of the natural starting point. Most of us tend to think one way about a problem: forward. Inversion allows us to flip the problem and think backwards.

   2. In the 1920s, the American Tobacco Company wanted to sell more cigarettes to women (women weren't smoking as much due to cultural differences). Instead of asking "How do I sell more cigarettes to women", they wondered "if women bought and smoked cigarettes, what else would have to be true? What would have to change in the world to make smoking desirable to women?"

   3. Another method is, instead of thinking through the achievement of a positive outcome, ask yourself how not to achieve a terrible outcome. Instead of thinking "how can I get rich?", think about how you can avoid staying poor.

4. Occam's Razor

   1. Simpler explanations are more likely to be true than complicated ones. Instead of wasting your time trying to disprove complex scenarios, you can make decisions more confidently by basing them on the explanation that has the fewest moving parts.

   2. There's a 10-acre reservoir in LA that contains around 60 million gallons of water which is disinfected with chlorine. However, to remain safe, it needs to be covered from sunlight. The Department of Water was debating making a 10-acre tarp or a huge retractable dome over the reservoir. But, using Occam's Razor, a biologist suggesting using "bird balls", which costed significantly less and was the most simple option!

5. Hanlon's Razor

   1. We should not attribute to malice that which is more easily explained by stupidity. Assuming the worst intent in people does more harm to us than good.

   2. In 1962 was the height of the Cuban missile crisis. There was a situation where the Americans had informed the Soviets that there were blank depth charges in the ocean to force the soviet submarines to the surface of the water. But the Soviet government failed to communicate this information back to the submarines deployed. So, when Arkhipov's ship experienced the detonations at the bottom of the ocean, the entire ship was convinced that the world was at war and they needed to deploy their nuclear weapon (which they were carrying). But Arkhipov chose not to, and went back to the surface to communicate with Moscow. If he had approved releasing the weapon, the world would have been a lot different than how it is today.