Why You Need to Reason by First Principles

Unmet expectations are the cause of all disappointment.

It's a jarring experience to have your model of the world fail, disproved, or collapse. Be it when someone responds unexpectedly, an idea you believed failing, or when your best judgement is wrong.

Your expectations are subverted by reality.

The underlying assumptions you had about the world proved wrong. The axiom you based your knowledge upon proved to be a bad model.

This is a common and inevitable experience.

Your view of reality is a low-resolution depiction. We are all operating the best we can under this condition, and it's the force behind a lot of pain.

With our finite knowledge, how can we operate best in a new environment?

The answer is first principles thinking.

First principles thinking is a process of decomposing a subject down to its fundamental axioms, reasoning up by asking which are relevant to the question at hand, and cross-referencing the conclusions based on the chosen axioms.

It's a concept used mainly in physics, but also, the other sciences, philosophy, and math.

An axiom is a self-evident or universally accepted truth. Think of it as a foundation upon which other knowledge is built.

All knowledge is conjecture, thus the only way to make progress is using axioms.

The experience of having your expectations subverted by reality is the result of the axioms you base your actions on. Your underlying assumptions (axioms) proved faulty.

By applying first principles thinking you can minimize the chance of this because faulty axioms are chiefly caused by implicit bias, lapses in judgement, and overly relying on past experience.

You can avoid a lot of pain by reformulating the assumptions you bring into a domain rather than carrying your biased and outdated assumptions of the past.

How do I apply first principles thinking in my life?

Simply put, it's breaking down complicated problems into their fundamental truths, and reasoning up from there.

First principles can apply to anything from brushing your teeth to building a business. It's useful to apply them when dealing with new situations, and when dealing with complexity. However, I'd recommend starting by applying them to the areas where you'd like to make progress.

For example, health, relationships, business, school, education, sports, etc...

For the sake of an actionable step-by-step guide, we'll walk through me using first principles thinking on going to the gym.

Step 1: Breaking down problems into the fundamental truths

First, let's define what we're breaking down.

Going to the gym is vague and people there have many differing goals. The question to ask is “What are we solving for?”. In the gym, you can focus on building muscle, gaining strength, becoming athletic, mastering your body weight for calisthenics, and more.

For this example, we'll solve for building muscle.

What am I as sure as possible is true?

• Resistance training stresses the muscle

• Progressive overload of the stress on the muscle induces hypertrophy

• The muscle is built during recovery

• Muscles need calories and protein to recover

Step 2: Create a conclusion based on the established axioms

Based on what we established as truths, how should we navigate?

Our goal is to build muscle so we should perform the proper actions in a repeated and cyclical fashion.

Use resistance training to stress the muscle.

After, spend sufficient time recovering: Sleep 8-9 hours or more, and don't train the muscle until it's recovered.

In the meantime, eat more calories than you burn and eat foods with high protein.

While you're still recovering the stressed muscle(s) train different muscles.

In essence, constantly keep yourself in a state of recovery while eating sufficient calories and protein.

This is done by routinely performing resistance training for different muscles on different days such that when you train them the next time they've recovered. A workout split is a schedule for muscle stressing and recovery.

Conclusion

Reasoning from first principles frees you from your assumptions and the constraint of others’ ideas.

If we'd used reasoning by analogy or convention for the prior example we'd have been led astray, as many are. Using those reasoning strategies you could decide to train a specific muscle every day with the idea that more is better.

In this context more is not better, and training a specific muscle every day is counterproductive to building muscle.

Stop making assumptions, stop strategizing based on convention, and stop letting others frame the problem for you.

Employ first principles to be an independent thinker that devises strategy based on understanding rather than analogy.