What is First Principles Thinking?
First principles thinking is problem-solving by breaking down complex issues into their most essential parts. Instead of copying solutions or relying on what others have done before, you start from scratch by identifying fundamental truths that cannot be denied.
This method involves repeatedly asking "why" until you reach foundational truths. Instead of relying on assumptions or conventional wisdom, you build your understanding from the ground up, focusing directly on root causes.
Once you understand these basics, you can grasp the subject deeply and build effective solutions step-by-step. Also, you can critically think and analyze new trends and decisions and avoid falling into the bandwagon effect.
Think of the following: Imagine you want to learn a new programming language. Instead of merely learning a trending language, you ask deeper questions: Why learn this language (for example, TypeScript)? What benefits does TypeScript provide compared to JavaScript? Why does static typing matter? How does it reduce bugs or improve scalability? Why not use a fully statically typed language like Java from the beginning? Etc etc.
By systematically exploring these questions, you dive into the fundamentals of programming languages, typing systems, and their practical impacts. This knowledge is evergreen because it rarely changes, and everything else is built on top of that. This enables you to adapt regardless of tech trends and stacks.
Recognize Patterns Across Different Fields
Pushing first principles thinking a step further is recognizing that many fundamental truths apply to different areas. When you spot these patterns, you can move your knowledge from something you already know to a new thing instantly.
Example:
If you deeply understand how recursion works in math (where a function calls itself repeatedly), you’ll quickly grasp recursive functions in programming because the underlying concept stays the same. A step further, you can assess if a recursion solution is better or worse than an iterative one.
If you have learn how the 80 / 20 rule works in capital you can use this to improve your productivity.
If you have learned how to be disciplined and focused in the gym you can use the same mechanism to be disciplined and focused in your work.
If you know how compounding works with money, you can utilize the same underlying principle to compound your skills.
How You Can Apply This as a Software Engineer
Exercising first principles thinking and pattern recognition in software engineering helps you adapt quickly to new technologies because you understand topics in-depth and recognize familiar patterns.
Backend Development Example:
Let's say you learned backend development using Express.js with TypeScript. You have understood essential concepts like creating APIs, handling requests, routing, and working with databases.
If you switch projects and have to use Python with FastAPI, you will see the same fundamental ideas: APIs still handle requests and responses, use routes, and interact with databases similarly. Even though the syntax differs, the basics remain similar.
Frontend Development Example:
If you’ve been using React, you already understand state management, components lifecycles, data flow, DOM and virtual DOM, and client-server communication. Moving to Vue.js becomes much easier because the foundational ideas are identical: Both rely heavily on components, manage state similarly, and have predictable data flow. M
TL;DR
Don’t learn technologies just because they're popular. Exercising first principles thinking will require more work and energy. But if you combine it with pattern recognition, you will become adaptable, effective, and evergreen—an engineer who thinks for himself and remains valuable regardless of trends and tech stacks.
