John Berger powerfully examined the way we view the world. But as for many people of my generation, who were captivated by his epoch-making television series on art Ways of Seeing, it is his manner of speaking that first comes to mind.

He spoke quietly, conversationally, with a tendency to poetic metaphors that made surprising, unexpected connections between art and other human activities. It was the same voice that you heard in his later writings — a seductive invitation to think and look together. It was the complete opposite of what until then we might have recognized as the voice of the art critic — sonorous, authoritative, and obviously the possessor of secrets available only to small selected groups. (That had been the tone of Kenneth Clark’s series Civilisation, broadcast a few years before Berger, whose implicit suggestion was that the critic’s unique gaze was privileged and exclusive.)

Berger, in that quiet way, unraveled the concept of civilization as a museum of great works into which we might be occasionally admitted to admire and gasp. Art, he told us, was not in the frame but in the space between the object and the observer, a contested area where inherited values, prejudices, and expectations, like fragments of glass, refract and divert our gaze.

He demonstrated this most trenchantly in his discussion of nude paintings. Quoting Levi-Strauss on “the avid and ambitious desire to take possession of the object for the benefit of the owner,” Berger argued that the naked woman is observed as an object and appropriated by the seer. It is a relationship of power and powerlessness since the gaze cannot be returned.

The painting (and for many years it was painting that he dealt with almost exclusively) in a capitalist society is an object of possession (just like the female nude), a commodity bought and sold, that represents ownership above all. Gainsborough’s Mr and Mrs Andrews, for example, are defined by the land that stretches behind and around them. The painting at once represents a propertied class to itself and is itself property.

Berger’s vision was explosive, not simply for the generation of art students who occupied their colleges in Britain in 1968, but for those of us who were actively in search of a philosophy of liberation, a politics that was both anticapitalist (though admittedly the phrase is more recent) and also held the promise of a more human, more creative future.

What we had until then was a Stalinist vision of art, in which art simply “reflected” (i.e. mirrored) reality or enacted ideological formulas. For Berger, art was subversive, questioning — it made the spectator explore how they made sense of the world, why they saw some things and were blind to others.

The implication was always that reality could be seen differently, and altered by our intervention. And that was revolutionary, because, as he put it, “the relations between what we see and what we know is never settled.”

Just as capitalism transforms the art object into commodities whose value is expressed as price, so too does it fetishize the artist. Picasso — as Berger explored in Success and failure of Picasso and in one of his most important essays, “The moment of Cubism” — was the most famous example.

At the beginning of the twentieth century, Picasso was a key figure in a movement whose art “was a dynamic liberation from all static categories.” The Cubists, Berger wrote, “did not think in political terms. Yet they were concerned with the revolutionary transformation of the world.” The bourgeois optimism reflected in family portraits and eternal nature was undermined and challenged, its eternal realities broken down and placed in motion. In Cubism, all that was solid could melt into air.

That was Picasso’s success; his failure, ironically, was the consequence of celebrity, of the taming of his revolutionary impulse. His brave, critical gaze became self-absorption, and as Berger’s introduction to an exhibition of the artist’s late work put it, his final drawings were “a sad entreaty,” an expression of the impotence and loss that fame had brought him.

Berger once described himself as “a Marxist among other things.” The enormous breadth of his work is breathtaking — essays, plays, films, stories, criticism, photography, novels. And his Marxism was inclusive of all of them, of the is and the ought, of the sustained criticism of capitalism and the regime of private property, and of the imaginative possibilities that can be awoken in everyone to reconstruct society.

In the early seventies, Berger left Britain for a farm in the Haute-Savoie. It may be that the angry assaults of the art establishment placed too many obstacles in his way. Or it may be that he left in search of a less alienated, more authentic way of life.

He had already become interested in photography, working with Jean Mohr on A seventh man, giving voice and a face to the migrants whom he saw, with prescience, as the new citizens of a changing world. Later, the trilogy Into their labours, beginning with Pig Earth, explored the relationship between the peasant and the land, which was more profound than simply property. But in all of this work, Berger sought out the imaginative universes that are not restricted to those designated as artists, the official dreamers of a world where even dreams are colonized.

Much of Berger’s later writing was storytelling, the fruit of the conversations he sustained with a vast range of people. For Walter Benjamin, the role of the storyteller was to capture and pass on collective wisdoms. There is a strong sense that this is what Berger also set out to do.

The impulse to explore the imaginative universe that Berger found in art seemed to have been drained in late capitalism. Post-modernism was mere surface, which refused access to what lay beyond it. The gaze was returned, merely mirrored, and the possibility of transformation denied.

“I now believe,” he wrote in the introduction to a later edition of Permanent Red, “that there is an absolute incompatibility between art and private property, or between art and state property . . . Property must be destroyed before imagination can be developed further . . . Thus today I would find the function of regular art criticism . . . to uphold the art market . . . impossible to accept.”

In the days since Berger’s death, some of the obituaries have been almost resentful, critical of his seriousness or his unbending commitment to a criticism that was “more conversation than evaluation.” Others have noted that his deeply personal narrative style, and the deep humanity it reflected, has produced no school of thought.

He was serious, it is true, but never miserable. He remained passionately convinced that solidarity with the voiceless was the duty of a Marxist, that capitalism was the bitter enemy of all creative labor, and that the seeds of a new vibrant and hopeful world could be found beyond the art academy, wherever human beings, however briefly, were able to shape their destinies.

He didn’t leave a school of thought, it’s true, but he helped form a generation for whom he made it possible to discover a different, critical way of seeing.