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Thinking and speaking are the same thing in the brain.

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The most words you've ever spoken in your life

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weren't to others;

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they were to yourself.

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From the moment you wake up to when you fall asleep,

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there is a never-ending monologue running in your head.

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You think this monologue is perfectly safe

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because it never leaves your mouth.

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No air vibration,

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no sound waves,

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no physical trace at all.

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It is your final domain of privacy.

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But in August 2025,

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a Brain-Computer Interface team at Stanford published a paper in Cell.

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The title was "Representation of Inner Speech in the Motor Cortex."

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This paper tells you one thing:

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Every word you say silently to yourself,

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your motor cortex is recording the entire time.

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Hello,

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everyone.

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I'm Wang Lijie.

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Let me recreate the scene of this experiment for you.

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Four patients who could not speak due to illness

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had microelectrode arrays implanted in their motor cortex.

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Researchers asked them to do one thing:

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Recite sentences silently in their minds.

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No need to try to make a sound,

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no need to move their lips—

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just pure internal thought.

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The result?

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Neural activity in the motor cortex was clear, stable, and decodable.

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Researchers used these signals to translate their internal thoughts in real-time.

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Accuracy reached 86% for a 50-word vocabulary,

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and even 74% for a 125,000-word vocabulary.

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More shockingly,

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the decoding speed matches normal conversational pace—

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145 words per minute.

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As you think a sentence,

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the machine writes it out simultaneously.

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What is the most counterintuitive finding here?

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It's that researchers discovered,

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when you think a sentence in your mind,

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neural patterns in the motor cortex are highly similar to when you actually speak.

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Not just vaguely related,

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not just a weak statistical signal,

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but structurally highly similar.

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The only difference is signal strength and certain dimensions,

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allowing algorithms to distinguish "thinking" from "speaking."

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But the underlying encoding pattern is almost identical.

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In other words,

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your motor cortex doesn't distinguish between thinking and speaking.

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To it,

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they are just two different volume levels of the same thing.

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You might say,

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"What's the big deal?

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Isn't this just another advancement in BCI?"

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No.

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What this paper truly shatters

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is an assumption we've never seriously questioned.

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We always thought

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that thinking and speaking are two completely different processes.

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Speaking

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is the output stage of converting thoughts into muscle movement.

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Thinking

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is a purely internal, private cognitive activity

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that involves no motor commands.

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We feel there's a wall between thought and speech.

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Thinking is inside the castle;

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speaking is outside.

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And there's a door in between that you can choose to open or close.

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But this paper says

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that door doesn't exist at all.

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You think you're just talking to yourself inside the castle,

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but the castle walls are transparent.

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The motor cortex prepares for speech from start to finish,

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it's just inhibited at the final moment.

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Thinking

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is not the prequel to speaking;

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thinking is just the low-power version of speaking.

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This makes me think of something.

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Buddhism has a concept called "the arising of a thought."

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For 2,500 years,

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practitioners has emphasized one thing:

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your thought itself is an action.

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It's not that thoughts lead to actions;

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the thought itself is already a form of movement.

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If a greedy thought arises in your mind,

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even if you don't reach out to take anything,

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on a karmic level,

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that thought has already planted a seed in your Alaya-vijnana.

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This sounds very mystical,

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right?

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You didn't actually do anything;

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you just thought about it.

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How can there be consequences?

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Now, this paper in Cell provides a precise neuroscientific footnote.

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Thinking isn't just a pure mental game.

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When you think,

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your motor cortex is actually executing it.

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It is firing neural signals.

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It is encoding specific phonemes and words.

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It goes through the entire process from intention to execution,

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short only of amplifying the signal to drive your vocal cords.

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Though this signal doesn't become sound,

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it is a real physical event.

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It changes your neural state.

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It consumes energy.

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It leaves a trace.

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Buddhism says arising thoughts create karma.

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Translated into neuroscience:

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every thought leaves an encoded trace in the motor cortex.

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Every repetition strengthens that neural pathway.

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You think it doesn't matter,

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but your brain doesn't see it that way.

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To the brain,

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thinking and speaking are separated only by an inhibition threshold.

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Repeatedly rehearsing a malicious sentence in your mind

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versus actually saying it out loud

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is nearly the same thing at the neural encoding level.

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This is why practitioners start with their thoughts,

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not just their behaviors.

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When you try to control your behavior,

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your motor cortex has already practiced it a thousand times.

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But the most interesting part of this paper to me

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isn't the confirmation of Buddhist concepts,

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but the researchers' own reaction.

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They identified a problem:

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if inner monologue can be decoded by a BCI in real-time,

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what about the user's privacy?

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If a paralyzed patient has a BCI implanted to help them communicate,

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but that device also captures thoughts

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they never intended to speak aloud, then what?

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They insult the nurse in their mind,

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and the device writes it out.

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They ponder inheritance plans mentally,

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and the device records that too.

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This isn't a sci-fi movie;

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it's an engineering problem.

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The research team proposed a solution in the same paper.

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They found that

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while the patterns of thinking and speaking are highly similar,

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there are dimensional differences that algorithms can capture.

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They used this to design a privacy protection protocol.

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One solution: the device only decodes when the user actively

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switches to a "speaking" mode.

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A more elegant solution: let the user set a mental trigger code.

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Only after thinking that specific password

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will the device activate the decoding function.

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You can think of it as an imaginary "power-on" command.

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Imagine that scene:

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scientists build a mind-reading machine,

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and in the very same paper, they install a lock on it.

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And what is the key?

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A password that only exists in your mind.

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This is the first time tech ethics and tech capability have debuted together in one paper.

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I think that alone is worth highlighting.

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Because for decades,

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the relationship between tech and ethics has been "act first, talk later."

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We discussed nuclear ethics only after the atomic bomb;

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we discussed algorithmic ethics only after social media addiction.

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We didn't discuss reproductive ethics until gene-edited babies were born.

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But this time is different.

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This time, the moment researchers saw what they had created,

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they immediately thought about how to constrain it.

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What kind of spirit is this?

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It is a kind of awareness.

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You know what you are doing.

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You foresee the consequences.

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And you respond simultaneously.

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It's not a post-hoc remedy.

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It's not someone forcing you.

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It's acting because you saw it yourself.

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Alright.

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Let's return to a deeper question.

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If thinking and speaking are different intensities of the same thing in the motor cortex,

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then what exactly is thinking?

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Is it a rehearsal for speech?

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Or is speech just an amplified version of thought?

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Vygotsky proposed a hypothesis a hundred years ago.

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He said,

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human inner monologue is the product of internalizing external language.

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Children start by talking to themselves out loud.

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If you observe three or four-year-olds,

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they talk to themselves while playing with blocks.

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Later, this self-talk gradually internalizes,

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becoming a silent inner monologue.

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So thinking isn't a prequel to speaking.

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On the contrary,

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speaking is the original version;

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thinking is the internalization of speaking.

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But this Cell paper carries an even more radical implication.

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Perhaps thinking and speaking have never been two separate things.

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Perhaps from the perspective of the motor cortex,

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all linguistic activity,

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whether voiced or unvoiced,

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is the same motor program.

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Sound is just an occasional byproduct of this program.

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Your brain doesn't think first and then decide whether to speak.

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Instead, it's speaking all the time,

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just most of the time you choose not to turn the volume up to the speakers.

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If this is true,

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then your inner monologue is not a quiet process of contemplation.

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It is a never-ending, low-volume speech.

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Your motor cortex is producing language every second,

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encoding phonemes, word order, and intonation.

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It is never quiet.

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The so-called silence is just you not hearing the external audio.

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This reminds me of a classic observation in practice.

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What is the first discovery meditators often report?

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"I never knew I had so many thoughts."

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When you first sit down quietly,

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doing nothing,

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you are shocked by the noise in your own head.

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Those thoughts aren't things you actively think.

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They pop up automatically.

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One by one,

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like scrolling comments on a screen.

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Now you know why.

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Because your motor cortex is always running.

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It doesn't need your instructions;

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it produces language on its own.

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This isn't a psychological phenomenon;

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it's a physiological one.

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Your brain is a language production machine that never stops.

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So what is meditation doing?

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If understood through the framework of this paper,

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meditation might be training you to reduce the frequency of this machine.

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Not to turn it off—

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you can't turn it off—

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but to make you aware that it's running,

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so you are no longer hijacked by its output.

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You hear the inner monologue,

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but you know it's just the automatic output of the motor cortex.

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It doesn't represent you.

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It doesn't equal reality.

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It's just a machine idling.

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This is what Buddhism calls Mindfulness.

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You see the thoughts,

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but you don't follow them.

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Finally, I want to ask a question.

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If brain-computer interfaces ever become truly common,

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and everyone has a chip in their brain,

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what would be the first thing to collapse in human society?

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I suspect it won't be privacy laws

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or business models,

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but the buffer between people we call "politeness."

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We can maintain a civilized society

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largely because we can separate thinking from speaking.

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What's in our hearts and what we say are often different.

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This isn't hypocrisy;

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it's a necessary cost for civilization to function.

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If this buffer zone disappeared one day,

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would humans become more sincere or more lonely?

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I don't have the answer,

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but I do know this:

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2,500 years ago, Buddha taught his disciples to practice starting with their thoughts.

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This may not just have been moral instruction.

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He may have already seen what this "Cell" paper

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only discovered today using electrodes.

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Your thoughts are not innocent bystanders;

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they are actions being executed.

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The only difference is the volume.

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What do you think?

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Do you think that wall between thinking and speaking

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actually exists,

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or is it just our wishful illusion?

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Let me know in the comments.

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I'm Leo Wang.

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See you next time.