Does natural language play a constitutive role in human thinking? Can we literally think in language, using sentences as vehicles of thought? I argue yes—but not in the way usually supposed.
The standard view holds that language-based thought involves dedicated neural mechanisms that manipulate linguistic representations. I propose an alternative: language-based thought is an intentional activity, something we do rather than something that happens in our brains.
Inner speech and conscious reasoning
My account centres on how language enables the formation of consciously held commitments. When you make up your mind about something, you’re not passively acquiring a new belief. You’re committing yourself to treating a proposition as a premise in your conscious reasoning, working out what it entails, and regulating your thoughts accordingly.
These commitments are typically formed and manipulated using natural language. We articulate premises to ourselves in inner speech, construct arguments by linking sentences together, and evaluate hypotheses by rehearsing them linguistically. Language provides scaffolding for active reasoning.
Inner speech plays a central role here. Following Peter Carruthers, inner speech involves the mental rehearsal of utterances—we initiate the motor commands for speaking while suppressing the actual movements, generating sensory representations (auditory images) that can be targeted by attention and globally broadcast. But inner speech is not just a format for thinking; it’s an activity whose functions are continuous with those of outer speech. This continuity thesis is supported by developmental evidence: children first use private outer speech to guide their behaviour (imitating the verbal guidance they receive from adults) and then internalize this as inner speech.
The cyclical model
Intentional reasoning follows a cyclical pattern: produce an utterance (or image), perceive it, interpret it as posing a subproblem, let autonomous processes generate a response, articulate that response, repeat. Intentional reasoning is, as I put it, a sort of deliberative mastication (chewing it over, as we say). The purpose of the actions involved is to break down the initial problem into simpler subproblems that can be solved by autonomous processes.
Deciding whether to attend a party might involve questioning myself (‘Do I really want to go?’), which evokes an automatic response (‘Henry will probably be there’), which poses a further subproblem (‘What will happen when I meet him?’), and so on, until I reach a conclusion. The process is formally similar to doing long division: breaking down a complex problem into simpler steps, each of which I can solve intuitively.
Conscious judgements and decisions are themselves linguistic acts. When I conclude my reasoning about the party by saying to myself ‘I won’t go’, I’m not expressing a pre-existing decision. I’m making a commitment to a course of action—committing myself to not going and to regulating my future reasoning accordingly. These self-directed commitments constitute distinctively conscious attitudes, which may differ from the unconscious attitudes formed by automatic processes. They play a stabilizing role in our mental lives, giving us self-awareness and self-control.
Language origins and the invention of invention
This language-involving cognitive activity constitutes a distinct level of mentality—what I call the supermind—which is realized in, but functionally distinct from, the basic mind we share with other animals. The supermind is a virtual system, created through culturally transmitted habits of thought rather than dedicated neural architecture.
The supermind’s emergence required two developments. First, as Daniel Dor has argued, language had to evolve from a system for sharing immediate experience into one for instructing the imagination—allowing humans to communicate about things distant in time and space. Second, humans had to discover how to use this capacity privately, applying to themselves the strategies of questioning and prompting they first developed for social interaction.
This explains how language-based cognition could have evolved so quickly (through cultural learning rather than neural rewiring), why System 2 reasoning has the features it does (they’re features of intentional action), and how humans became genuinely creative and innovative. Through language, we created new minds for ourselves: conscious, reflective, capable of sustained deliberation. We invented the very capacity for invention.
Key publications
Natural language and virtual belief (1998) — I argue that some beliefs—virtual beliefs—are actively formed by adopting premising policies, and that forming them typically requires language. Virtual beliefs are realized in basic beliefs about one’s cognitive commitments. Language provides the scaffolding for articulating, manipulating, and evaluating these commitments. In P. Carruthers and J. Boucher (eds.), Language and Thought. Cambridge University Press.
Evolving the linguistic mind (2010) — I examine how language-based cognition could have evolved, arguing that the linguistic mind is a virtual system created through culturally transmitted habits rather than new neural structures. The supermind emerged when humans privatized and internalized social practices of argumentation.
Inner speech and outer thought (2018) — I reconcile two apparently conflicting views: that inner speech provides a format for conscious thought, and that it’s an activity continuous with outer speech. Conscious thinking is an intentional activity that follows a cyclical pattern—produce an utterance, interpret it as posing a subproblem, generate a response, articulate it, repeat. This activity can be conducted overtly in private speech and is then internalized as inner speech. Conscious judgements and decisions are self-directed commitments expressed in speech.
Popular writing
Our greatest invention was the invention of invention itself (2022) — Drawing on Daniel Dor’s account of language origins and Dennett’s theory of consciousness, I argue that hypothetical thinking emerged through cultural evolution. Language enabled humans to instruct each other’s imaginations, and inner speech privatized this process, creating the conscious mind as a virtual system. This capacity for mental self-stimulation was the invention that made sustained innovation possible. Psyche.
Related topics
The two-level mind—Virtual beliefs and premising policies
Dual-process theories—System 2 as self-stimulation
Illusionism—The virtual mind and consciousness
