First principles thinking has been a key part of my approach to life since my early twenties. And when I look back at choices I’ve made and said ‘oops, that wasn’t a good call’ I can almost always point to a choice I made without applying first principles thinking. So I try to use it more often than not for any significant decision, even less consequential ones (like, should I buy the television on Amazon Prime Day!) I didn’t buy it, btw.
If you become interested in using first principles thinking I suggest you read more than this article. I put this together as primer for my friend, peers, colleagues, strangers, etc. who occasionally will ask me to explain first principles thinking, almost always in the context of us trying to work through a problem or question. This is truly just a primer, there is more to this method of thinking than is here but this will get you started and give you enough of base to start using it in your own world.
Okay, so what does it mean to use first principles thinking? Well, first principles thinking means breaking a problem down into the most basic facts you know are true, then building your answer from those facts.
Most of the time, people solve problems by copying what already exists.
They ask:
How do other people do this?
What is the normal approach?
How can we improve the current process?
First principles thinking asks a different question:
What must be true, even if we ignore how things are usually done?
Then it uses those basic truths to design a solution from scratch. Now, don’t get me wrong, this is harder and more time consuming at first. As you intentionally use it more and challenge yourself to think this way more it’ll become more and more natural to you, to the point that it just becomes an almost default way of thinking - and becomes an efficient way to think and make decisions.
A simple example
Suppose you want to travel from New York to Washington, D.C.
A normal approach might be:
Most people take a train, drive, or fly. Which of those should I choose?
First principles thinking starts deeper:
I need to move about 225 miles.
I need to arrive by a certain time.
I have a certain budget.
I may need to carry luggage.
Different forms of transportation have different speeds, costs, and levels of convenience.
Only after identifying those facts would you compare trains, cars, buses, flights, or some other option.
This may lead to the usual answer. But it might not. The important difference is that you did not assume the usual answer was correct.
And this is real, I often hear people - making this exact trip - default to a mode of transport without much thinking. They just say ‘I take the train [or bus or plane or whatever]" without processing the base line (or core) facts and principles - making a decision in the moment rather with an intentionally thought out plan. They defaulted to what they (or others) always do.
Why it matters
Many bad systems continue to exist because people improve them without questioning their basic structure.
Imagine a company has a process that requires employees to complete a 20-page form.
A normal improvement might be:
Let us make the form easier to use.
First principles thinking might ask:
What information do we actually need?
Why do we need it?
Who uses it?
Which information already exists somewhere else?
Do we need a form at all?
The result might be a shorter form, an automated process, or no form whatsoever.
The goal is not simply to make the old process better. The goal is to solve the actual problem.
And this is just as true in people’s personal lives.
Imagine someone feels overwhelmed because their house is always cluttered.
A normal improvement might be:
Let us buy better shelves, bins, and organizers.
First principles thinking might ask:
Which belongings do we actually use?
Why are we keeping everything else?
Where do items naturally get used?
Why does clutter keep returning?
Do we need better storage, or fewer possessions?
The result might be donating unused items, keeping everyday objects closer to where they are used, and creating simpler routines for putting things away.
The goal didn’t change: create a home that is easier to live in. But how you achieve that goal does become better, because instead of defaulting to an answer you do the root analysis of the problem to build a solution. The result will be that you didn’t just organize clutter which will ultimately result in disorganized clutter once again in a pattern that continually repeats but with more and more clutter each time, it will be an elimination of clutter, a process for organizing and storing what you truly do need in a way that makes life simpler, and an approach to avoiding clutter in the future.
The basic method
Now, this is high-level but it will provide you a good foundation to use first principles thinking in your life. And, frankly, for most things people deal with day to day this four step approach will get you about 90%+ of the benefits of a first principles thinking approach.
1. Define the real problem
Be careful not to confuse the current solution with the actual problem.
“The problem is that our approval process is too slow” may not be precise enough.
The real problem might be:
Every business day that we delay making a contract modification decision reduces our chance of deal closure by 5% so we want to minimize decision delay while controlling financial and legal risk.
That definition opens up more possible solutions.
2. Identify assumptions
Write down what you are currently treating as true.
For example:
Every request needs three approvals.
Approvals must happen in order.
Managers must review every request.
Requests must be submitted through a form.
Some of these may be facts. Others may simply be habits.
3. Find the basic truths
Ask what is actually required. This is where you should be challenging assumptions. Do you really need this or that? What is the measurable downside to eliminating this or that? What is the measurable upside to including this or that?
Perhaps:
High-risk requests need careful review.
Low-risk requests rarely cause problems.
The company needs a record of important decisions.
Certain decisions legally require approval.
These are closer to first principles because they describe real needs rather than the current process.
4. Build a solution from those truths
You might conclude:
Low-risk requests should be approved automatically.
Medium-risk requests need one reviewer.
Only high-risk requests need three approvals.
Reviews can occur at the same time rather than one after another.
That solution comes from the underlying requirements, not from tradition.
What first principles thinking is not
This is a primer, so I want to be a bit soft but I also don’t want to lose the value. As you become more used to applying first principles thinking you’ll naturally use it more. The cost of questioning things goes down because you build your brain wiring such that running through the four steps for many things is quick and natural.
Now, don’t just reject experience. Existing solutions often exist for good reasons. Make sure you take a moment to understand why they exist, that will inform your understanding of the principles at play.
It also does not mean questioning every tiny detail. That would waste time. But, as I said, as you get better about it this becomes less of an issue.
Also, be careful overapplying this to decisions that don’t need it. There will be things you just decide: regardless of whether this survives a first principles analysis this is what we want to do. That’s perfectly fine, but acknowledge that is what you are doing - don’t lie to yourself and others.
First principles thinking is most useful when:
The current approach is expensive (time, money, values, culture, etc.) or ineffective.
People (often yourself) say, “That is just how it is done.”
A problem has resisted normal improvements.
Technology or circumstances have changed.
You are designing something new.
The central idea is simple:
Do not begin with the current answer. Begin with the facts that any good answer must satisfy.
Full Disclosure: AI was used to assist in drafting some sections of this post.