The problem with first-principles thinking is that you don’t know what you don’t know. You might end up deriving the same thing you could have read in a 101-level textbook. You might think you have a novel idea of a blockchain-powered utopia but it turns out it’s Georgism with extra steps.
On the other hand, first-principles thinking solves the problem that you don’t know what other people don’t know. People make mistakes in their thinking that may directly or indirectly influence your thinking. Godel’s incompleteness theory tells us that there are always things we don’t know.
Now we have a conundrum—you don’t know what you don’t know and you don’t know what everyone else doesn’t know.
So when should you apply first-principles thinking?
Low epistemic status ahead!
As the default on the edge and as a counterbalance in the middle.
Imagine knowledge about a given area of inquiry is a two dimensional field (e.g. distributed computing, socialism, space travel, etc.). Beyond the edge is the unknown. The further you move from the center the longer the path of propositions that must hold true for that point to also be true.
At the edge, first-principles thinking is essential. New technology, techniques, and ideas can make finding new knowledge possible. Uncovering flaws in the long line of propositions that got the field to the edge of what’s known can also be fruitful. Perhaps there was something wrong that is easier to see from the edge looking back.
In the middle, being dogmatic about first-principles thinking is a reductionists trap but a useful counterbalance. If you never think from first-principles (even in the well-trodden middle) you’ve essentially outsourced your thinking.