There is a difference between knowing something vaguely and understanding it deeply. We often sit and nod through meetings, lectures, or books feeling like we “get it,” but when we sit down to explain it to someone else or put it into writing, our minds freeze, our thoughts tangle, and our confidence might even crack; that is Kiddlin’s Law in action.

Kiddlin’s Law states: If you can not write it down clearly, you do not understand it well enough.
It is a simple yet deep idea and it applies far beyond writing. Kiddlin’s Law is not just about communication skills; it is a measure of our mental clarity, the depth of our understanding, and our ability to think precisely. And in today’s world of noise and half-baked hot takes, it is more relevant than ever: You do not truly understand it until you can write it.

Table of Contents

The Origin and Meaning of Kiddlin’s Law

Though it is not as famous as Murphy’s or Parkinson’s Laws, Kiddlin’s Law captures a core truth of intellectual life. While after my research I am still unsure about the origin of the quote because it is attributed variously to anonymous engineers, writers, and teachers, the principle is echoed by countless thinkers through time.

If you can not explain it simply, you do not understand it well enough.
Albert Einstein

Richard Feynman taught students to test their understanding by pretending to teach the subject to a child.

Everything that can be said can be said clearly.
Philosopher Ludwig Wittgenstein

Kiddlin’s Law sits in this same family of thought: Clarity is the byproduct of understanding, and vagueness is often the mask of confusion. If your ideas are messy on paper, they are likely messy in your mind, obviously.

Why Writing Reveals the Gaps in Your Thinking

Most people think they understand something until they try to write it.

Writing is not just transcription; it is reflection; it takes what you “think you know” and drags it into the light, exposing holes, assumptions, and contradictions; it forces decisions: What do I mean here? What comes first? Why does this matter?

When you write, you confront the limits of your own knowledge and you realize:

You have memorized terms but do not know how they connect.
You have absorbed opinions but have not formed your own.
You have heard the message but have not thought it through.

And maybe, subconsciously, that is why writing is so often avoided by some, if not many; it is mental labor, and yet, it is also one of the fastest ways to refine your thinking. As one of my favorite philosophers and author Jordan Peterson put it:

If you can think and speak and write, you are absolutely deadly. Nothing can get in your way.
Jordan Peterson

Writing is thinking made visible; it reveals confusion, but it also sharpens clarity.

Clarity as a Sign of Mastery in Real Life

Kiddlin’s Law is not just for writers and philosophers; it is for anyone who wants to make better decisions, lead effectively, or create meaningful work.

In Teaching

A teacher who can not explain a concept clearly does not know it well enough. Kiddlin’s Law pushes educators to not just repeat what is in the textbook but to translate understanding into relatable, digestible words.

In Business and Leadership

Great leaders break complexity into clarity, because vague visions create confused teams. Clear writing, be it in an email, strategy memo, or proposal shows sharp thinking and and it also inspires trust.

In Content Creation

If your blog, article, or video script is muddled or messy, your readers will not stick around, so the best creators make hard ideas simple, not simple ideas hard, and so know that Kiddlin’s Law is the difference between noise and real substance.

In Personal Decision-Making

When you are facing a tough decision, write it out. Articulate the options, the risks, the desired outcomes, and you will be surprised how clarity on paper leads to confidence in character and in life.

How to Think and Write More Clearly

And so this article begs the question, how do we live out Kiddlin’s Law in practice? Here are just five ways to train your mind for clarity:

Use the Feynman Technique

Pick a topic you “know,” and try explaining it in writing as if teaching a 12-year-old. When, if and where you stumble, you still need clarity. Fill the gap and repeat.

Replace Fancy Words with Precise Ones

Big words do not equal smart thoughts. “Utilize” can often just be “use,” and “Facilitate” might just be “help.” Good writing aims for precision, not pretension.

Outline Before You Write

Random thoughts do not lead to clarity, structure does, it is structure that leads to clarity. Outlining helps you organize ideas, it helps you spot gaps and inconsistencies, and it helps you see the logic or lack of it in your flow.

Read Your Writing Out Loud

If it does not sound clear to your ear, it will not be clear to your reader or listener. Reading aloud exposes awkwardness, ambiguity, and what is wrong in your sentences.

Revisit and Revise

Writing is rewriting, so do not just stop at the first draft, because what each revision can do is to bring you closer to expressing what you really mean.

Conclusion

Kiddlin’s Law is more than a writing tip; it is a philosophy of understanding, an invitation to slow down and wrestle with what you think you know in a world that is obsessed with fast takes and constant output. This law, Kiddlin’s Law, calls us back to depth and clarity.

So when you force yourself to write things down clearly, you are not just becoming a better communicator, you are becoming a sharper thinker. And sharp thinking leads to better choices, better work, and definitely a better life.

So the next time you feel like you understand something, do not just say it. Write it! And let the clarity or the confusion show you where you really stand. Because in the end, if you can not write it down clearly, you probably or even very likely do not understand it.

Kiddlin’s Law: Why Clarity in Writing Reveals Clarity in Thought