In the late 1960s Joseph Kosuth emerged as a leading theorist of what came to be called Conceptual Art. In 1969 he published “Art After Philosophy,” a three-part essay that served as a kind of manifesto for this movement. Kosuth argued that modernist art had reached a dead end: instead of producing new styles of painting or sculpture, artists now needed to think about the nature of art itself. As he succinctly put it, being an artist in the 1960s meant “to question the nature of art. If one is questioning the nature of painting, one cannot be questioning the nature of art…” . In other words, artistic practice had to shift from how art is made to why art is art – from mere objects to ideas. Kosuth’s famous dictum that “the actual works of art are the ideas” encapsulates this view. He insisted that conceptual art is not about aesthetics or objects at all, but about ideas and meanings: the artwork is the concept or proposition, rather than a material thing. As one historian notes, conceptual art “proclaims itself to be an art of the mind rather than the senses” . In Kosuth’s view, art becomes essentially linguistic and logical: the artist speaks with concepts.
Kosuth’s essay explicitly severed art from traditional aesthetic concerns. He argued that the branch of philosophy called aesthetics – which deals with beauty, taste, and perception – is fundamentally separate from the project of art itself. “It is necessary to separate aesthetics from art,” he writes, because aesthetics concerns opinions about the world at large, whereas art’s role is different . In this section of the essay he “assert[ed] that art is analogous to an analytic proposition, and that it is art’s existence as a tautology which enables art to remain ‘aloof’ from philosophical presumptions” . In plain terms, Kosuth means that art does not aim to depict or describe reality, nor to satisfy empirical or decorative functions; instead, like an analytic truth in logic, art simply is. This was a direct critique of the formalist modernism then dominant (for example, the Greenbergian emphasis on painting’s inherent visual qualities). Kosuth saw formalism as an ideological stance that tied art to taste and convention, which he rejected. By divorcing art from beauty or utility, Kosuth insisted that art’s only “function” is self-referential: art exists for its own sake and about itself .
A key philosophical source for Kosuth was analytic philosophy of language and logic, especially Ludwig Wittgenstein and A. J. Ayer. Wittgenstein taught that the meaning of a word is determined by its use in language, and that tautologies (statements true by definition) say nothing about the world. Kosuth absorbed these ideas. Indeed, he opens one section of Art After Philosophy by quoting Wittgenstein: “‘The meaning is the use.’” . This emphasizes that in art, as in language, meaning arises only through the context and conventions in which symbols (words, objects, images) are used. Later Wittgenstein famously noted that tautologies are trivially true and carry no substantive content; Kosuth took this to heart. He viewed artworks themselves as analogous to logical propositions.
Kosuth explicitly applies the analytic–synthetic distinction drawn by A. J. Ayer (a prominent British philosopher) to art. Quoting Ayer’s definition — that an analytic proposition is true solely by virtue of its terms, whereas a synthetic proposition’s truth is determined by external facts — Kosuth adapts this to art . He argues that “the validity of artistic propositions is not dependent on any empirical, much less any aesthetic presupposition about the nature of things. For the artist, as an analyst, is not directly concerned with the physical properties of things…” . In Kosuth’s view, a work of art is not a statement about some object or event in the world but a statement about art itself. “The propositions of art are not factual, but linguistic in character,” he writes; they “express definitions of art, or the formal consequences of definitions of art” . In short, conceptual artworks function like analytic truths: their meaning is contained in their terms and in the context of the art language game, not in any observable subject matter. He even declares outright that “works of art are analytic propositions. They say nothing about any matter of fact” . This is why he can say art is art: when we label something a work of art, that labeling itself is the whole point.
This leads to the most famous line of Kosuth’s manifesto: “Art’s only claim is for art. Art is the definition of art.” . Kosuth here is embracing the tautological nature of art. By this provocative statement he means that art only refers back to itself; calling something art is in a sense self-fulfilling. If we try to define art by external criteria – beauty, skill, emotion, or factual content – we step outside art into mere aesthetics or documentation. For Kosuth, the only legitimate statement an artwork can make is that it is art. Thus any attempt to talk about art without realizing this ends up repeating a tautology, which he sees as inevitable. He observes: “It is nearly impossible to discuss art in general terms without talking in tautologies – for to attempt to ‘grasp’ art by any other ‘handle’ is to merely focus on another aspect… which is usually irrelevant to the artwork’s ‘art condition’” . Art’s “art condition,” in his account, is conceptual rather than formal or representational. In effect, conceptual art reframes itself as a form of logic or mathematics: it can be appreciated entirely within its own conceptual system (“the art idea and art are the same and can be appreciated as art without going outside the context of art for verification” ).
The philosophical implications of this stance are far-reaching. If the artwork is the idea, then the ontology of the artwork is entirely mental or linguistic. As the Stanford Encyclopedia of Philosophy explains, Kosuth’s view “claims that the conceptual artwork itself is to be identified with the idea that may be seen to underlie it,” and this “affects the ontology of the conceptual artwork” . In other words, an artwork no longer has to exist as a physical object at all; instead its being lies in the realm of thought or definition. This transforms the role of the artist as well. Instead of a craftsman or image-maker, the conceptual artist becomes more like a philosopher or mathematician – a thinker working with concepts and language . The early conceptualists (following Kosuth) therefore often “de-materialized” art: the primary “material” of a work might be words, definitions, instructions, or even an empty concept. The artist’s gesture is to nominate or present the idea, effectively making the thought-process the artwork.
Kosuth’s own works illustrate these points. His best-known piece One and Three Chairs (1965) presents a wooden chair, a photograph of the chair, and the dictionary definition of “chair,” inviting the viewer to consider which is the real chair and how the concept of “chair” exists in different media. Similarly, his series Titled (Art as Idea as Idea) consists of words like “meaning,” “representation,” and “theory” – essentially exhibiting language itself as art. These exemplify the Wittgensteinian notion that the meaning of a sign is its use: by isolating and displaying words and definitions, Kosuth turns meaning-making into a public, self-examining act. As one scholar notes, Kosuth’s approach “proclaims [conceptual art] to be an art of the mind rather than the senses” . The semantic (meaning-based) representation he employs aims to “transmit clearly formulated ideas” and to engage the viewer intellectually .
Historically, Kosuth explicitly linked his ideas back to Duchamp. He saw Duchamp’s readymades as the crucial precedent for conceptual art – the point at which art turned from objects to ideas. Duchamp had challenged the artworld by declaring ordinary manufactured objects (a bicycle wheel, a urinal) to be “art,” thereby implying that designation rather than aesthetic labor is what counts. Kosuth picks up this thread. He writes that conceptual art “followed through with what [Marcel Duchamp] had proved with his readymades: art presupposes the existence of an aesthetic entity fulfilling the criteria of what should be art. As was the case with Duchamp’s readymades, [Kosuth] declared them to be art and they became art” . In Duchamp’s terms, “if someone calls it art, it is art.” This institutional definition is echoed in Kosuth’s statement “Art is the definition of art” and later formalized in Minimalism by Donald Judd’s quip that the only criterion for art is that it be called art . Kosuth extends Duchamp’s insight by insisting not only that any object can be art, but that the idea or concept is the art.
Kosuth also attacked the modern art establishment of his day. He saw critics like Clement Greenberg (advocate of Abstract Expressionism and Color Field painting) as politically and culturally conservative gatekeepers. Greenberg’s form-based judgments, Kosuth argued in interviews, were tied to the status quo (Greenberg even supported the Vietnam War, Kosuth noted) and to outmoded notions of taste . By contrast, Kosuth saw conceptual art as radical and anti-authoritarian. In the turbulent context of the late 1960s – student protests, the Vietnam War, Civil Rights struggles – he felt that accepting any predetermined hierarchy of styles (including Greenbergian formalism) was untenable. His call to question “the nature of art” rather than merely painting was thus also a political statement: it challenged the “tyranny of formalist modernism” and insisted that art should be about ideas and critique . Not coincidentally, Kosuth co-founded the so‑called Museum of Normal Art (a counter‑institutional gallery space) in 1967 and curated shows like Fifteen People Present Their Favorite Book, which mocked the idea of a solitary genius artist.
This institutional dimension became a recurrent theme in Kosuth’s later practice. He eventually staged large installations in major museums (for example The Play of the Unmentionable at the Brooklyn Museum in 1990) that juxtaposed his own conceptual works with historical works and exhibition texts. In doing so he made the museum itself an object of analysis, showing that context – labels, gallery text, institutional setting – helps produce an artwork’s meaning. As one commentator observes, Kosuth “orchestrates combinations of textual, visual or archival artefacts to investigate… the museum as container and promulgator of [ideas]” . In this way he explicitly highlighted the institutional conditions of meaning: by curating the context, he demonstrated that what counts as art is often decided by those in the art world.
Cultural critics have noted that Kosuth’s philosophy essentially revived the spirit of Dada for a new era. Like Duchamp before him, he rejected the commodification of art and the fetish of the art object. Instead art became an intellectual activity, akin to logic or science. Kosuth himself said that he believed “art was an intellectual activity” and thus that philosophy could “only survive through being art” . He saw conceptual art as the logical continuation of Modernism’s endgame: once painting had explored all formal possibilities (Frank Stella’s black paintings, for instance, were taken to exemplify “art for art’s sake”), what remained was to focus on art’s concept. In Sol LeWitt’s famous phrase (antecedent to Kosuth), “in Conceptual art the idea or concept is the most important aspect of the work” . Kosuth took this to heart and made his writing itself a crucial part of the movement. Art After Philosophy reads more like a philosophical treatise than an art essay: it cites philosophers (Ayer, Wittgenstein) and logicians, and it frames art as a series of propositions.
One of the subtle aspects of Kosuth’s essay is its self‑reflexivity. He demonstrates his point in the very way he writes: Art After Philosophy itself often reads like a demonstration of art as concept. For example, he annotates his essay with numbered footnotes and margin comments that mimic a Logical Positivist paper, and he uses phrases like “by art’s definition we mean….” In effect, the essay is an instance of his thesis. Arthur Danto later quipped that Art After Philosophy “may indeed itself be a work of art,” underlining how the text enacts conceptual art’s principles .
In sum, Joseph Kosuth’s Art After Philosophy stakes a radical claim: art is not about objects, beauty or representation but about ideas and definitions. Kosuth boldly concludes that art’s very nature is self‑referential and logical – “Art is the definition of art” – meaning that art only claims its own status. This has the effect of shifting the focus of art entirely onto language and concepts. Artists after Kosuth took up this challenge by making works that were texts, instructions, or questions. The essay’s insistence on the primacy of ideas over objects deeply influenced how we think about art’s ontology: it opened up a view of art as a form of analytic inquiry. It also deepened the already tenuous boundary between art and philosophy: conceptual art, Kosuth argued, is in a sense art-as-philosophy or philosophy-as-art.
Kosuth’s manifesto remains controversial. Its claim that art is essentially tautological (“if something is called art, it is art”) seems to make art trivially broad – any concept could be art if the context says so. Critics ask: does this make the category of art empty or meaningless? Kosuth would answer that precisely because art is an “open concept” (à la Morris Weitz) it cannot be pinned down by fixed criteria. The role of conceptual art was to continually question those criteria, to keep art thinking philosophically about itself. In this respect Art After Philosophy stands as a rigorous and uncompromising call for an art that thinks of itself – an art of ideas whose meaning is generated by language and context rather than by traditional aesthetics.