What Actually Is a Thought? And How Is Information Physical?

“The map is not the territory.” — Alfred Korzybski

“Information is physical.” — Rolf Landauer

“Between stimulus and response there is a space.” — Viktor Frankl

A story to begin: the pianist in the scanner

Dear reader, allow me to take you into a quiet hospital room where a young pianist lies inside an MRI scanner. The researchers have asked her to imagine the first bars of Chopin—no fingers moving, no sound in the air. The machine hums; a computer draws shifting patterns of color. As she hears the music in her mind, certain parts of her brain brighten: areas for sound, memory, and even the ghostly trace of finger movements. When she switches to Bach, the pattern changes—related, but distinctly shaped.

This is the simple wonder: a thought leaves a footprint. It is not mist or magic. It is a living pattern, a brief shape woven by billions of tiny electrical whispers. That shape guides what we notice, how we feel, and what we do next.

In this essay, I will argue—plainly and carefully—that a thought is a patterned, energy-using process in the brain; that it is a map of something (real or imagined); that it has shape in the language of brain activity; and that information, including the information in your thoughts, is rooted in the physical world. I will also show you why ancient wisdoms—from the Upanishads to Stoicism—often sound surprisingly modern when they talk about the life of the mind.

“We are a way for the cosmos to know itself.” — Carl Sagan

1) So, what is a thought?

Let us keep this definition simple and strong:

A thought is a short-lived pattern of brain activity that carries meaning.

It could be a picture (“my mother’s face”), a plan (“turn left at the next street”), a feeling (“uneasy”), or a question (“what if?”). It lasts seconds, sometimes less, and it can be spoken, acted on, or simply fade.

Three ideas help:

• Aboutness. A thought is about something. Philosophers call this intentionality. The pattern points beyond itself, the way the word “tree” points to trees.
• Shape. The brain does not switch on like a single bulb; it forms coordinated patterns. Different contents make different patterns—different “shapes”—across the brain’s networks.
• Cost. Thoughts use energy. Your brain runs on oxygen and glucose. To think is to spend.

“Cogito, ergo sum,” wrote Descartes—“I think, therefore I am.” Today we might add: I think, therefore I burn a tiny amount of fuel, and I rearrange the patterns that will make tomorrow’s thoughts easier or harder to have.

2) The brain’s orchestra: how patterns appear

Picture an orchestra in which every musician can hear every other musician, and yet there is no single conductor. Instead, brief leaders emerge: a violin phrase pulls the winds; a drum cue quiets the brass; then the melody hands off again. That is your cortex at work.

• Neurons as players. A single neuron is a tiny battery. It builds up charge, fires a spike, and rests. One spike means little; choruses of spikes—thousands together—carry messages.
• Assemblies as musical phrases. When certain neurons often fire together, their connections strengthen. Next time a part of that group sparks, the rest tend to follow. Psychologist Donald Hebb summarized it neatly: “Neurons that fire together wire together.” These learned groups are called cell assemblies.
• Attractors as favorite tunes. The brain’s activity lives in a constantly shifting landscape. Some patterns are stable “valleys” that activity falls into—like favorite melodies the orchestra knows well. These are attractors. A familiar face or a well-practiced skill is such a valley.
• Working memory as spotlight. When you hold a phone number in mind, or decide what to say next, you keep a pattern active for a few seconds. Psychologists call this working memory. It is the brain’s spotlight, moving from one pattern to the next, sharing the stage with sensation and emotion.

“No nucleus of thought exists without a neighborhood.” — William James (paraphrase)

Timing matters. Brain regions “speak” in rhythms—slow waves for long-distance coordination, faster ripples for local detail. When rhythms line up, signals pass; when they fall out of step, they hush. A thought is therefore not only which neurons fire but when they fire together, like dancers catching the same beat.

3) The chemistry beneath the music

Every thought rides on chemistry—fast sparks and slow tides:

• Glutamate and GABA are the main messengers. Glutamate excites; GABA calms. Think of them as the gas pedal and the brake that keep patterns crisp instead of chaotic.
• Acetylcholine narrows attention, sharpening the edges of what you perceive.
• Dopamine highlights novelty and reward. It whispers, “Remember this; predict that.”
• Norepinephrine adjusts alertness—too little and you drift, too much and you tremble.
• Serotonin helps regulate mood and flexibility, smoothing sharp corners of reactivity.
• Neuropeptides (such as oxytocin and stress hormones) set the background weather—trust, threat, tenderness, drive.

Learning changes the hardware itself. When a pattern repeats, tiny knobs on neurons (called spines) grow or shrink; receptors move; genes turn on; proteins are made. This process—plasticity—is how today’s thoughts become tomorrow’s habits. At night, during sleep, the brain often “replays” the day’s patterns, training them into more permanent form. In short, chemistry rewrites structure, and structure shapes the thoughts you can easily think.

4) The geography of mind: how thoughts are maps

When scientists measure many neurons at once, they can plot brain activity as a cloud of points in a space with many dimensions (one dimension per neuron or per pattern of firing). For a given idea—say, the taste of cinnamon—that cloud tends to live in a certain region. For another idea—your dog’s bark—the cloud lies elsewhere. Related ideas lie in neighboring neighborhoods. This picture is called a neural manifold. It is a fancy term for a simple truth: the brain organizes meaning as shapes and neighborhoods.

Your brain also uses literal maps in tissue. The visual map preserves the layout of the eyes; the touch map lays your body across a strip of cortex; the sound map arranges tones by pitch. When you think, you recruit and recombine these maps. That is why imagining music nudges auditory maps, and recalling a walk around your block tickles maps of space.

“The real voyage of discovery consists not in seeking new landscapes, but in having new eyes.” — Marcel Proust

5) The physics of information: do thoughts have “weight”?

Here we must be careful and clear. Two statements are both true:

1. Information is physical.
   Information is not a ghost. Storing, comparing, and erasing information require physical work. This is a foundational result in physics associated with Rolf Landauer. Every time a device—or a brain—resets a tiny memory, it pays a tiny energy cost. No way around it.
2. The “weight” of a thought is unimaginably small.
   Because energy and mass are two faces of the same coin (Einstein’s E=mc^2), any energy use has a mass equivalent. But the amount involved in a single thought is far below anything we could measure on a scale. A hard day of thinking does not make your head heavier. The brain’s total power draw—roughly the energy of a dim light bulb—mostly keeps neurons ready to react; intense thinking shuffles that budget rather than multiplying it.

So, when people say thoughts have “shape” and “weight,” shape is literal (a reproducible pattern in brain activity), while weight is a poetic way to say: thinking consumes real energy and leaves tiny, physical traces in the brain’s wiring. The poetry is rooted in physics, but the pounds and ounces stay the same.

“Whereof one cannot speak, thereof one must be silent.” — Ludwig Wittgenstein

(A caution not to push metaphors beyond their measure.)

6) Old wisdom, new science: where traditions meet the lab

It is striking how often ancient reflections sound modern when we translate them into today’s language.

• The Upanishads separate manas (the sensing mind), buddhi (discernment), and ahamkara (the “I-maker”). We might hear: sensation, attention, and the self-model your brain keeps updating.
• Buddhism speaks of momentary mental events (cittas), conditioned by causes and passing quickly. That sits well with the view of thoughts as short-lived patterns.
• Stoicism distinguishes impressions from assent: the world strikes us with images and feelings; our wiser self decides which to embrace. Neuroscience would say: perception proposes; prefrontal networks dispose.
• Aristotle wrote about potential versus actual intellect. In brain terms: many patterns are possible; a thought is the pattern that becomes actual for a brief time.

“Mind alone is the cause of bondage and liberation.” — Amritabindu Upanishad

“You have power over your mind—not outside events.” — Marcus Aurelius

The resonance is not proof, but it is encouragement. Our ancestors watched their minds closely. We add measurements and microscopes; the human puzzle remains the same.

7) A friendly reckoning: are thoughts “just” brain states?

Here is my considered view for you, the thoughtful reader:

• A thought is not less than a brain state; it is more than any single description of that brain state.
• Music is both air vibrations and melody. Likewise, thought is both ions and insight. If we only talk ions, we miss meaning; if we only talk meaning, we ignore the engine that makes it possible.

This middle path is humble and hopeful. It says: explain as far as we can, measure carefully, and leave room for the lived texture that cannot be reduced to one layer of description.

“Mind is what the brain does.” — Marvin Minsky

(Yes—and also what the person does with what the brain makes possible.)

8) Practical notes for daily life: shaping the shapes

What good is this knowledge if it doesn’t help us live better? Here are practical, grounded implications:

1. Repetition carves ruts—use that wisely.
   Practicing a skill or a mindset (gratitude, problem-solving, kindness) makes its pattern easier to enter next time. Habits are the grooves of thought.
2. Protect sleep like a precious appointment.
   Sleep is when the brain “replays” and consolidates. It is also when emotional tone resets. A tired brain misreads maps.
3. Move your body to clear your mind.
   Exercise improves blood flow, stress chemistry, and the growth of new connections. Motion refuels cognition.
4. Feed the machine.
   Balanced nutrition supports the brain’s energy needs and chemistry. Spikes and crashes in blood sugar fog maps and decisions.
5. Curate your attention as you would your diet.
   Inputs become priors. Doomscrolling trains your brain to expect doom; deep reading trains it to keep a stable, nuanced pattern alive.
6. Name your thoughts.
   Simply labeling—“a worry,” “a plan,” “a memory”—creates a little space. As Frankl said, in that space is your freedom.
7. Use many codes.
   Speak, write, draw, gesture. Each format recruits different brain maps and makes the idea sturdier.
8. Practice recovery, not just effort.
   Mindfulness, prayer, breathing exercises, time in nature—all are ways to quiet noisy patterns so healthier ones can take the stage.
9. Seek good company.
   Brains influence brains. Calm minds calm minds; courageous minds kindle courage. Our patterns are contagious.
10. Choose worthy attractors.
    If you return each day to envy or outrage, you deepen those valleys. If you return to curiosity and service, you deepen those instead.

9) A brief return to the story: the map that became a lamp

Let us visit the pianist once more. After the scan, she sits at a real instrument. Her fingers now move. The inner map becomes outward music. Chemistry keeps time, rhythms coordinate, memories stabilize the flow. From a tiny burn of fuel and the flex of living tissue, the room fills with sound. A thought has crossed from a silent pattern to a public act. The map has become a lamp, throwing light for others to see by.

“The real act of discovery consists not in finding new lands but in seeing with new eyes.” — Attributed to Proust

That is, finally, the promise of understanding thoughts as physical, patterned, and trainable. It does not shrink the mind; it grounds it, so we can grow it. If we honor the costs, we can learn to spend them well. If we respect the shapes, we can choose better ones. And if we remember that maps are not the territory, we can still use them to travel far.

Closing opinion, plainly stated

In my judgment, the most fruitful way to think about thinking is this: a thought is a brief, meaningful shape in a living brain; information is the discipline by which those shapes are stored, compared, and changed; and because storage and change require energy, information is inescapably physical. The poetry of “shape and weight” rests on that plain physics. The dignity of your mind rests on something simpler still: your freedom to cultivate better shapes—steadier, kinder, truer—and to let them guide your hands in the world.

“You become what you give your attention to.” — Epictetus

May we, then, give our attention to what enlarges us and those around us. May our inner maps be honest and our inner lamps bright.