The philosophy of intersubjectivity is one of the most important and complex developments in 20th-century thought. It addresses a fundamental problem: How can separate, subjective consciousnesses share a common, objective world? It moves philosophy beyond the isolated Cartesian cogito ("I think") to the foundational recognition: "We are."

Intersubjectivity is not merely "communication" or "empathy." It is the structural condition of possibility for any shared reality, objective knowledge, or genuine social life.

Core Definition

Intersubjectivity is the philosophical term for the shared, reciprocal, and constitutive relationship between conscious subjects. It is the process by which:

I recognize you as a subject like myself (not just an object in my world).

I understand that you also experience a world from your perspective.

We mutually constitute a shared world that is neither yours alone nor mine alone, but ours.

It is the bridge between the subjective (private, first-person experience) and the objective (public, third-person fact).

The Problem Intersubjectivity Solves

Without intersubjectivity, philosophy faces two insurmountable problems:

Solipsism: The inability to prove that other minds exist at all.

Relativism: The fragmentation of reality into incommensurable private worlds.

Intersubjectivity argues that the shared world is not a lucky coincidence of separate minds, but is actively, collaboratively built into the very structure of consciousness and social life.

Major Philosophical Frameworks of Intersubjectivity

1. Edmund Husserl: The Foundational Phenomenology

Husserl, the father of phenomenology, made intersubjectivity a central problem in his later work (notably the Cartesian Meditations).

The Problem: Phenomenology begins with the first-person perspective ("the transcendental ego"). How can it escape this starting point to account for the objectivity of the world and the existence of others?

The Solution: Analogical Apperception. I perceive your body (Körper) as behaving like mine. By a transfer of sense, I apprehend it as a living body (Leib) inhabited by another ego—an "alter ego." I do not infer your subjectivity; I appresent it directly in perception.

The Shared World: The objective world is not my private representation, but an "intersubjective transcendental constitution." The world is "there for everyone" because it is co-constituted by a community of monads.

2. Alfred Schutz: The Lifeworld of Everyday Life

Schutz applied Husserl's insights to sociology, founding phenomenological sociology.

The Reciprocity of Perspectives: In everyday life, I assume that if we exchanged places, we would see the same world. This is a practical, taken-for-granted fiction that makes social life possible.

The "We-Relationship": The face-to-face encounter (Umwelt) is the primordial sphere of intersubjectivity, where we experience each other as "growing old together" in a shared present.

Social Reality: The entire social world—institutions, roles, knowledge—is built upon these sedimented, intersubjective typifications.

3. Maurice Merleau-Ponty: Intersubjectivity as Intercorporeality

Merleau-Ponty radicalized intersubjectivity by grounding it not in consciousness but in the body.

The Flesh of the World: My body and yours are not separate substances but different folds in the same flesh of the world. I understand your gesture not by analogy, but because I inhabit a similar body. Your smile is directly meaningful; I do not decode it.

Chiasm: The touching hand and the touched hand are reversible. This reversibility is the model for intersubjectivity: I am touched by your gaze even as I see you; we are intertwined.

Implication: Intersubjectivity is not a secondary achievement of isolated minds. It is co-primary with subjectivity itself. I am from the beginning a being-among-others.

4. Jürgen Habermas: Communicative Intersubjectivity

Habermas shifted intersubjectivity from consciousness to language and communication.

From Consciousness to Communication: The Cartesian "I think" is replaced by the We-speak of communicative action.

Universal Pragmatics: In any act of communication, speakers implicitly raise validity claims (truth, rightness, sincerity) that are addressed to an intersubjective community of hearers. Meaning is not in the speaker's head, but in the public, shared space of language.

Lifeworld and System: The intersubjectively shared lifeworld (background consensus, cultural knowledge) is the resource from which communicative action draws. Its colonization by impersonal systems (money, power) is the central pathology of modernity.

5. Emmanuel Levinas: The Ethical Primacy of the Other

Levinas offers a radical inversion: intersubjectivity is not symmetrical, and it is not primarily about knowledge or constitution. It is about ethics.

The Face of the Other: The Other (Autrui) is not an alter ego to be comprehended, but an absolute, transcendent alterity that commands me. "Thou shalt not kill."

Asymmetry: I am infinitely responsible for the Other before the Other is responsible for me. This responsibility is pre-original—it precedes my freedom, my choice, my being.

Critique of Husserl: Levinas accuses the entire phenomenological tradition of reducing the Other to a constituted phenomenon, thereby committing an act of epistemic violence. True intersubjectivity is not comprehension but proximity, substitution, and hostage.

6. Existential Intersubjectivity: Heidegger and Sartre

Heidegger: Dasein is fundamentally Being-with (Mitsein). The world is always already a with-world (Mitwelt). Others are not added to a pre-existing self; the self is constituted through its relations with others. (This is often inauthentic in the mode of das Man, but the structure is primordial.)

Sartre: Intersubjectivity is conflict. The Other's Look (le regard) objectifies me, steals my world, and reveals my vulnerability. "Hell is other people." Yet, this very struggle for recognition is constitutive of my self-consciousness.

Applications and Implications

Psychoanalysis (Intersubjective Turn): The mind is not a self-contained system but is formed and transformed within the intersubjective field of the analytic dyad (Stolorow, Atwood, Benjamin).

Social Theory: Social reality is not an aggregation of individual actions but is constituted and maintained through shared typifications, language, and mutual recognition.

Cognitive Science (Enactivism): Cognition is not a private computational process but is enacted through embodied interaction with others and the environment (Varela, Thompson, Di Paolo).

Political Philosophy: Recognition is not a psychological nicety but a fundamental human need and a condition for justice (Axel Honneth's theory of recognition).

AI and Posthumanism: Can non-biological agents participate in intersubjectivity? Or is it uniquely embodied and mortal?

Conclusion: The Primacy of the Between

The philosophy of intersubjectivity represents a paradigm shift from the philosophy of the solitary subject to the philosophy of the relation itself. It asserts that:

Subjectivity is not prior to intersubjectivity; they are co-emergent.

The world is not mine or yours, but ours.

Meaning, truth, and value are not private possessions but public, negotiated, shared accomplishments.

The self is not a substance but a node in a network of recognition.