Some philosophers have argued that thinking and language are two sides of the same coin—thinking as inner language, and language as externalized thought. But this perspective doesn’t quite hold up to scrutiny.
The broader consensus is this: language is the expressive form of thought. Theoretically, all content needs some form in which to exist. As the old saying goes, “Without the skin, where would the hair attach?” But forms come in two kinds: external multimodal forms that can be seen or sensed by others (such as written or spoken language, audio-visual works, etc.), and internal forms—those invisible carriers of thought like neural activity and brainwaves.
Content and form are indeed two sides of the same coin, inseparable in function. Yet, only internal form is indispensable to thinking itself. In practice, large language models (LLMs) represent content as internal vectors—tensors that encode meaning in a computable way. This internal form is known in neural networks as the “latent space.” As Ilya once said, the biological brain likely functions via a similar stream of electrical pulses in the biological neural network. Although this isn’t yet a scientific consensus (since brain science still lags far behind AI's advance), it offers a helpful lens to understand the relationship between internal thought and externalized language.
The notion that thought and language are tightly connected, yet still separable, becomes more fascinating the deeper you think about it. Philosophically, it remains debatable. But the emergence of large language models provides a living analogy—like wave-particle duality. Thought is like a wave; language, as a sequence of discrete symbols, resembles particles in a stream. Consciousness itself is akin to light, exhibiting both behaviors.
What exactly is the form of thought in the brain? How does it interact with or get translated into language—whether spoken or written? We may never fully know from biology alone. But artificial neural networks already give us a convincing glimpse: they encode thoughts as internal vectors, which can be transformed into language through input/output ends like embedding/softmax layers. If language is clothing, then the internal thought chain is a naked stream of consciousness—what we might call "naked thought"—only collapsing into definite symbolic string when forced through verbalization.
Why, then, do we so often feel that thought and language are inter-dependant? A few key reasons are as follows:
First, humans are social beings. We feel an innate urge to share what’s on our minds. We don’t just daydream in solitude—we talk, message, meet. Our inner thoughts and feelings struggle to stay bottled up for long. (Exceptions exist, such as in cases of autism.)
Second, without external forms, our thoughts are fleeting and often lack coherence. Set aside the hidden states inside machine learning models—just look at the human brain. Without the scaffolding of language, our wild ideas rarely stretch into long lines of reasoning. We can't build up knowledge, nor pass it on. No accumulated knowledge means no science, no civilization. That's why language, along with artistic creations, is so crucial to advance of humanity. These external modalities are also the fuel behind the current AI revolution.
Despite having far more neurons than even the largest language models, the human brain is vastly limited in its ability to store and organize knowledge. No matter how brilliant, no individual can match a large model’s breadth and depth. The defeat of the world Go champion by an AI was a vivid example—"tofu brain" versus silicon, simply an unfair fight. Our brains lack both long-term storage and precision. That’s why we need decades of education and training just to stand on the shoulders of past generations and inch forward. This reinforces our intuitive sense that complex thinking requires external form.
Third, culture shapes cognition. Though, in principle, the mind can operate on internal brainwaves and pulses without external representation, the advent of language has changed the landscape. For tens of thousands of years, humans have encoded, transmitted, and reinforced thought through external forms. Over time, especially among the literate, we’ve internalized the habit of thinking in linguistic terms—even silently. Studies show that brainwaves representing thought often align with subtle movements of the speech organs. Silent reading easily slips into self-talk. This reinforces the illusion that thought and language are one and the same.
We now know that LLMs trained with reinforcement learning generate outputs in a "query–COT–answer" sequence. The input (query) and output (answer) are necessarily language, because they interact with human users. But the middle part—COT, or chain-of-thought—can either be fully verbalized or remain as latent reasoning. The latter sacrifices interpretability but might yield better results.
So what about us? Does the human brain also harbor these silent, unspoken internal chains of reasoning? Or are we fundamentally bound to language in order to think at all? There’s long been debate. Most of us feel that without language, extended, organized reasoning is nearly impossible. Only in dreams or moments of deep reflection do we experience vague, inexpressible insights that seem to precede words.
In theory, “thinking” is narrower than “consciousness,” and language is but one modality among many. The inner referent of multimodal signals is best described not as thought alone, but as “conscious experience.” From this angle, the thought-language relation is just one special case of the broader relationship between consciousness and modality. Saying “language = thought” is as flawed as saying “consciousness = modality.”
So, what is consciousness? The ancients might say: “The brain thinks, the heart feels.” The former we call thought; the latter, emotion. Why do we associate emotion with the heart rather than the brain? There’s no scientific basis. But emotional states often come with noticeable changes in heartbeat or blood pressure. When love strikes, it’s “heart-throbbing,” not “brain-throbbing.” Feelings like doubt, admiration, jealousy, or compassion don’t feel like products of cold logic of brains. Regardless of their biological seat, emotions are an essential component of consciousness. Animals may experience basic emotions too, just as they may have rudimentary language. But human emotions are uniquely rich and nuanced.
So if thoughts and emotions are both internal, how do they manifest externally?
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Through language: the most direct and common mode of expression.
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Through music: melody and rhythm convey feelings where words fail.
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Through visual arts: painting, sculpture, film—each captures aspects of what can hardly be said.
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Through embodied gestures: hugs, kisses, waves, thumbs-up, middle fingers, even fists. Eye contact, laughter, tears—they all fall under the category of embodied intelligence, the domain of future humanoid robots.
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Through inexpressibility: what cannot be put into form, what remains ineffable—too subtle even for art.
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Setting embodiment aside, the relationship between consciousness and modality is essentially the relationship between internal content and external form. Among all modalities, language remains kernel—especially as a carrier of thought. Emotions can be described in language, but such descriptions often feel clumsy, dry, or distorted. Consider the blind musician Abing, who poured his life’s suffering and aspirations into a two-stringed erhu performance, “The Moon Over a Fountain.” No language could ever capture what that music conveys.
So, after this long detour, we return to the question: Is thinking the same as language?
Conclusion:
Thinking is a core component of consciousness—its inner content or meaning. Language is a primary modality—its external form or medium. Thus, to ask whether thought equals language is really to ask whether content equals form, whether consciousness equals modality. Given that the brain can internally represent thought in neural form, thinking does not depend entirely on language. The internal neural network exists independently and proves that “thinking = (external) language” is an oversimplified claim. Still, it doesn’t rule out the assumption that “thinking = internal language” might be true.
