What is the difference between First Principles and Induction?

Let's put it this way: these two concepts are like two completely different approaches to "learning how to cook."

"Inductive Reasoning" is like "learning to cook by following recipes."

Imagine you want to learn how to make Kung Pao Chicken. You find ten highly-rated recipes and notice they all call for chicken breast, peanuts, and sautéing aromatics like green onions, ginger, and garlic first. From this, you deduce a rule: "To make successful Kung Pao Chicken, you must follow this process and use these ingredients."

This is inductive reasoning. You observe many successful examples (recipes), summarize a general pattern or rule, and then follow it. Its advantages are speed, reliability, and a lower chance of error, because you're treading a path already proven by others. In daily life, we use inductive reasoning most of the time, for instance, "All the neighbors' kids go to tutoring, so ours should too," or "Everyone in this industry does business this way, so we should too." This is about learning from and imitating others.

"First Principles Thinking," on the other hand, is about "starting with culinary chemistry."

You don't want to look at any recipes. Instead, you start by researching the most fundamental questions:

• At what temperature does protein (chicken) become most tender?
• What are the conditions for the Maillard reaction (the source of flavor) to occur?
• What happens to sugar at high temperatures (caramelization)?
• How does the crispiness of peanuts come about?

You break down the act of "making a dish" into its most basic physical and chemical principles. Once you understand these, you're no longer limited to the "Kung Pao Chicken" recipe. You can use pork, beef, or even tofu instead of chicken; you can substitute cashews for peanuts; you can even invent a completely new, yet equally delicious, dish.

This is first principles thinking. It doesn't care how others do things, nor what "tradition" or "experience" dictates. It focuses on one thing: returning to the most core, fundamental point (physical laws, human nature, mathematical axioms, etc.), and from this "absolutely correct" starting point, step-by-step deriving conclusions and methods.

To summarize the core differences:

• Inductive reasoning is "looking backward" or "looking sideways." It relies on past experiences and others' methods, representing "analogical thinking." For example, if a carriage isn't fast enough, inductive thinking would lead to "finding stronger horses, building lighter wheels" – making improvements within the existing framework.
• First principles thinking is "looking downward," getting to the bottom of things. It disregards existing frameworks, returning to the essence of a matter, embodying "physics thinking." For example, instead of "how to make a carriage faster," it asks "what is the essence of rapid movement?", which might ultimately lead to the invention of the automobile.

Simply put, inductive reasoning teaches you how to make a candle burn brighter and longer; first principles thinking, however, asks "why do we need light?", and might then lead to the invention of the light bulb.