What Is Thinking?
Philosophical and Scientific Perspectives on the Most Mysterious Human Activity
We all think, almost constantly. We weigh decisions, solve problems, daydream, remember, reason, worry, and wonder. Yet for something so central to our lives, thinking is remarkably hard to define. Is it what your brain does? Is it the voice in your head? Is it conscious, unconscious, abstract, emotional, logical?
Ask a neuroscientist, a philosopher, a psychologist, and a Buddhist monk what thinking is, and you'll get very different answers. Each discipline captures a facet of the puzzle, but none fully contains it.
This post is tour of how different fields have tried to answer the deceptively simple question: What is thinking?
Thinking as Neural Activity: The Scientific View
From a scientific perspective, especially in neuroscience, thinking is often treated as the coordinated firing of neurons in the brain. When you solve a math problem, recall a memory, and imagine the future, different networks in your brain light up and interact. Chemical and electrical signals pass between billions of neurons, producing the phenomena we call thought.
This approach has yielded profound insights. Scientists can now identify brain regions involved in language, memory, emotion, and moral reasoning. But there’s a limit: knowing which brain areas are active doesn't tell us what it feels like to think or how brain activity translates into meaningful content. A brain scan may show that you’re processing language, but it can’t tell if you're composing a poem or silently arguing with yourself.
Thinking as Reasoning: The Philosophical View
Philosophers have long equated thinking with reasoning—the use of logic to draw conclusions, make judgments, and evaluate evidence. In this tradition, to think well is to think clearly, using structured arguments, valid inferences, and sound principles.
This idea reaches back to Plato and Aristotle and finds modern expression in logic, rationalism, and critical thinking. René Descartes, in his famous declaration “I think, therefore I am,” used thought as the undeniable proof of personal existence.
But this view is also narrow. It privileges formal reasoning while ignoring emotional, sensory, and intuitive modes of thought. Most of what occupies our minds day to day is not syllogisms and logic puzzles. We think in stories, images, feelings, and fragments. Reason is only one note in the mental symphony.
Thinking as Inner Speech and Imagination
Another way to define thinking is as inner experience—what it’s like to have a mind. This includes inner speech (the voice in your head), visual imagination, mental rehearsal, spontaneous associations, and even musical earworms.
The psychologist Lev Vygotsky argued that much of thinking begins as inner speech—a silent dialogue with ourselves. Others, like philosopher Daniel Dennett, suggest that consciousness itself is a kind of narrative we tell ourselves in real time.
Still others argue that we often think without words—through images, emotions, and body sensations. A musician composing in their mind, or a chess master instantly “seeing” a position, may not engage in any inner dialogue at all.
Thinking as Meaning-Making
At its core, thinking may be best understood as the process of making sense of the world. Whether through logic, imagination, memory, or association, we are constantly trying to impose order, find patterns, assign causes, and construct meaning from experience.
This definition encompasses both conscious and unconscious thought. You don’t decide to think about your surroundings or make a story out of events—it happens automatically. Dreams are a kind of meaning-making, weaving fragments of memory into surreal narratives.
In this light, thinking is not something we do, but something that happens to us—a continuous, mostly involuntary attempt to interpret the world and our place in it.
Thinking Beyond the Brain: The Extended Mind
A growing number of philosophers and cognitive scientists argue that thinking doesn’t happen only in the brain. According to the extended mind theory, our environment, tools, shared language, and social interactions are part of the thinking process.
When you use a notebook to remember something, or a calculator to solve a problem, are those external tools part of your thinking? What about a conversation that helps clarify your thoughts? Or a drawing that lets you "see" an idea?
This perspective challenges the idea of the mind as sealed within the skull. It suggests that thinking is distributed across the brain, body, tools, and culture.
Thinking versus Feeling, or Both?
Many traditional views separate thinking from feeling—as if emotion is irrational and thought is cold and logical. But modern research shows this division is false. Emotions are deeply intertwined with cognition. They guide attention, shape decisions, influence memory, and help us prioritize what matters.
Even so-called "rational" thinking often begins with a gut sense and emotional leaning. Antonio Damasio, a neuroscientist, found that people with damage to emotional centers in the brain could reason logically—but were paralyzed when making everyday decisions. They could weigh pros and cons endlessly, but nothing felt more important than anything else.
In short, we do not think in spite of emotion—we think through emotion.
Thinking About Thinking: Metacognition
One of the most fascinating aspects of thinking is our ability to reflect on it. This is called metacognition—thinking about our own thinking. It includes awareness of how we learn, evaluate ideas, and monitor our reasoning.
Metacognition is a hallmark of human intelligence. It allows us to question our biases, double-check our reasoning, and learn from mistakes. It also makes us vulnerable to doubt, self-deception, and overthinking.
Thinking about thinking is both a gift and a curse—but it's also where philosophy, mindfulness, and critical thinking begin.
A Moving Target
So what is thinking? A flow of neurons? A silent conversation? Pattern recognition? Abstract reasoning? Emotional processing? A social act? Just a part of an intermeshed larger biological process?
The truth is, thinking is not one thing—it is many things. It’s a complex, layered, and dynamic process that defies easy boundaries. Like water, it changes form depending on context: fluid, structured, turbulent, still.
As we continue to explore the brain, build intelligent machines, and reflect on our minds, the question “What is thinking?” will remain open.