Mental models are how you understand the world. They not only shape what you think and how you understand it but they shape the connections and opportunities that you see. Mental models are how you simplify complexity, why you consider some things more relevant than others, and how you reason.

A mental model is simply a representation of how something works. You cannot keep all of the details of the world in your brain, so you use models to simplify the complex into understandable and organizable chunks.

A mental model is a concept, framework, or worldview that you carry around in your mind to help you interpret the world and understand the relationship between things. Mental models are deeply held beliefs about how the world works. Mental models guide your perception and behavior. They are the thinking tools that you use to understand life, make decisions, and solve problems. Learning a new mental model gives you a new way to see the world.

Mental models are imperfect, but useful. There is no single mental model from physics or engineering, for example, that provides a flawless explanation of the entire universe, but the best mental models from those disciplines have allowed us to build bridges and roads, develop new technologies, and even travel to outer space. As historian Yuval Noah Harari puts it, “Scientists generally agree that no theory is 100 percent correct. Thus, the real test of knowledge is not truth, but utility.”

The best mental models are the ideas with the most utility. They are broadly useful in daily life. Understanding these concepts will help you make wiser choices and take better actions. This is why developing a broad base of mental models is critical for anyone interested in thinking clearly, rationally, and effectively.