Most people reason by analogy. We see a problem and think, “What similar situations have I seen before?” This is fast and often effective. It’s why we use recipes to cook or follow best practices at work. You're essentially copying a proven solution with slight modifications. But this approach has a ceiling. It only allows for incremental improvements on what already exists. To create something truly new, you need a different mental model.

This is often called reasoning from first principles. Instead of looking at past examples, you break a situation down into its most basic, undeniable truths—the axioms. Then, you build your solution up from there. It's like ignoring the recipe and asking, “What do I know for a fact about how heat, protein, and salt interact?” This is the “physics way of thinking” that innovators like Elon Musk famously use.

When Musk wanted to build rockets, the conventional wisdom said they were astronomically expensive. By analogy, a new rocket would cost tens of millions. But he didn't accept that. He asked: what is a rocket made of? Aerospace-grade aluminum alloys, titanium, copper, and carbon fiber. Then he asked: what is the commodity market value of those materials? It turned out the raw material cost was only about 2% of the typical price. The rest was bloat from traditional manufacturing processes and supply chains. By deconstructing the problem to its core physical components, SpaceX found a path to building rockets for a fraction of the cost.

This isn't just for building rockets. You can apply this deconstruction process to nearly any complex system, from a business model to a career path. The goal is to strip away every assumption until you are left only with things you know to be true.

Imagine you want to pivot your career. Reasoning by analogy might lead you to look for jobs with similar titles or in adjacent industries. First principles thinking forces you to ask deeper questions:

• What are my fundamental skills? Not “I am a marketer,” but “I am good at communicating complex ideas, analyzing data, and persuading people.”
• What is the core purpose of a job? To create value in exchange for compensation.
• What do I truly want? Financial security, creative autonomy, helping others?

By breaking the problem of “career change” into these axiomatic truths, you are no longer limited by existing job descriptions. You can re-synthesize the components into something entirely new—maybe a freelance consulting business, a new product idea, or a role in a completely unrelated field that happens to need your core skills.

The key is to relentlessly question your assumptions. When you think something is true, ask yourself why you believe it. Is it a fundamental truth, or is it something you've absorbed from others, from convention, or from past experience? Keep digging until you hit a bedrock of facts you cannot break down any further. That's your first principle.

If this method is so powerful, why doesn’t everyone use it all the time? The simple answer is that it's hard. Reasoning by analogy is our brain's default setting because it's energy-efficient. Deconstructing a problem from scratch is time-consuming and mentally demanding. It requires intense focus and a willingness to be wrong.

Now, let's review the core ideas before you test your knowledge.

Ready to check your understanding?

By mastering deconstruction, you equip yourself with a powerful tool to move beyond incremental improvements and start creating genuinely new solutions.