Welcome to the 750+ new members of the curiosity tribe who have joined us since Friday. Join the 24,766 others who are receiving high-signal, curiosity-inducing content every single week!Today’s newsletter is brought to you by AppSumo!AppSumo was founded with one goal in mind: to give entrepreneurs the tools they need to grow their businesses, at a fraction of their regular cost. To do this, AppSumo partners with the hottest tech companies and gets you insane deals on their products and services. You’ll save money and discover exciting, up-and-coming technologies. I’m a customer, you should be too. Check it out below to take advantage!Today at a GlanceInversion is a simple, powerful mental model for solving complex problems.When problems become challenging to solve forwards, they may be more readily solved backwards.Inversion has a wide variety of applications, ranging from investing to business to leadership to relationships.Invert, Always InvertThe world is an exceptionally complicated and competitive arena. On any given day, you wake up, encounter a wide array of challenging, multivariate problems, make decisions with highly-imperfect information, and then plan to do it all over again the next day.To outperform in this complicated and competitive arena, you need serious problem-solving skills. Fortunately, contrary to what many of you have been told, these skills can be learned.Today, I’d like to cover inversion - a simple, powerful mental model for thinking clearly and solving complex problems.The History of InversionWhen solving problems, the human mind is wired to think in linear, logical, forward terms. This is (probably, I’m not a scientist!) due to the types of problems our ancestors faced - avoiding getting eaten by large animals, hunting other large animals, searching for the next meal, etc. These problems were inherently ephemeral and discrete - they had clear lines of action/reaction and obvious allies and enemies. But as humanity entered the Agricultural Age, followed by the Industrial Age, followed by now the Digital Age, our problems seemed to change. They got much more complex. As Notorious B.I.G. famously said, “Mo technology, mo problems” (or something like that?). As the problems get increasingly complex, the forward, logical process evolved in our ancestors often fails. Enter our simple, powerful mental model: inversion.Let’s start with the basics. What is inversion?Inversion is a mental model and thinking tool used by some of the world’s greatest thinkers and problem solvers. Simply put, it says that when problems become challenging to solve forwards, they may be more readily solved backwards.Inversion as a general thinking tool has been around for millennia. Stoic philosophers would perform an exercise they called “premeditatio malorum” - roughly translating to “the pre-meditation of evils” - in which they would imagine the worst case scenario ahead of time. They believed that this exercise would force them to engage in behavior and make plans to avoid this outcome.The more formal mental model was popularized by German mathematician Carl Jacobi in the mid-1800s. Jacobi was famous for his work in advancing the field of elliptic functions. Wikipedia tells me elliptic functions are “a special kind of meromorphic functions, that satisfy two periodicity conditions” - which provided approximately zero clarity, so I’ll just stick to my lane.When faced with difficult problems (which happened frequently!), Jacobi had a strategy: “Man muss immer umkehren.”The loose translation: “Invert, always invert.”Jacobi frequently used this strategy if he were to be stumped on a challenging math problem. Rather than continuing to look at it the same way (forwards), he would restate it in inverse form (backwards). This new, creative perspective often allowed him to solve the problem more easily.Fast forward 100+ years and inversion went mainstream when Charlie Munger made one classic, quintessentially pithy remark:“All I want