Can Plato's Theory of Forms be regarded as an application of first principles?

This is a very interesting question. I think Plato's Theory of Forms can be seen as a very ancient, very philosophical "spiritual ancestor" of First Principles Thinking. They are quite similar in their way of thinking, but differ in their application domains and the "principles" ultimately derived.

Let me explain with a simple example.

First, let's talk about Plato's Theory of Forms.

Imagine the concept of a "bed." You've seen wooden beds, iron beds, single beds, double beds... all sorts of beds. Plato would argue that none of these beds we see in the real world are "truly" beds; they are all merely imperfect copies of the "Form of Bed."

In his view, in an unseen, eternal "World of Forms," there exists a most perfect, standard, and unchanging template of a "bed" (this is the "Form of Bed"). All artisans in our world, in fact, are trying their best to imitate and create it based on a vague memory of that perfect template in their minds. Therefore, to gain true knowledge about "beds," you shouldn't study the millions of different beds in reality, but rather use your reason to contemplate and grasp what that sole, perfect "Form of Bed" truly is.

Now, let's look at First Principles Thinking.

A modern exemplar of this mindset is Elon Musk. When he wanted to build rockets, he didn't look at existing rockets on the market and say, "Let's try to make it 10% cheaper." Instead, he asked the most fundamental question: "What are the basic materials needed to build a rocket?" The answer: aerospace-grade aluminum alloy, titanium, copper, carbon fiber, and so on. Then he asked, "What is the price of these materials on the international market?" He discovered that if a rocket was broken down into its most basic raw materials, the cost was only 2% of the quoted price of a rocket at that time.

You see, he wasn't constrained by the commonly accepted "common sense" at the time that "rockets are expensive." He broke down the complex object of a rocket all the way back to its most fundamental, irreducible physical components and economic costs, and then, starting from these "first principles," rethought how to build an inexpensive rocket.

So, where are they similar?

They both emphasize one thing: Don't be misled by appearances, traditions, or existing examples; penetrate beyond the surface to find the most fundamental, core, and unchanging "essence" or "principle."

• Plato sought to penetrate the ever-changing "copies" in the real world to find the unique "perfect template" in the World of Forms.
• First Principles Thinking seeks to penetrate existing products, prices, and solutions to find the most basic physical laws, material costs, and other "factual axioms" that constitute the thing.

What, then, are their key differences?

The biggest difference lies in what that "ultimate principle" is.

• Plato's "Forms" are metaphysical and abstract. They exist in a spiritual world, a perfect, a priori concept. You "discover" them through philosophical contemplation.
• The "principles" of First Principles Thinking are physical and real. They are physical laws, mathematical formulas, and the cost of basic materials. You "calculate" and "verify" them through scientific analysis and deconstruction.

To summarize:

So, you can understand it this way: Plato's Theory of Forms, over 2000 years ago, taught people how to think using first principles in a philosophical way. It provided a powerful thinking framework – to discard the false and seek the true, to explore the essence. What we call First Principles Thinking today, however, applies this ancient framework to more specific fields of science, engineering, and business, using a more rigorous and quantitative approach to find that "essence."

One could say that Plato was the one who looked up at the stars, contemplating "what is ultimate beauty"; while Musk is the one who looks down at the ground, calculating "what is the minimum cost to build a rocket." Their paths of pursuit are very similar, but one leads to the temple of philosophy, and the other to engineering marvels.