Nineteenth-century sculpture was captive to an academic convention: the body idealised, the surface polished smooth as marble, the pose noble and calm. Auguste Rodin broke that convention. His "Age of Bronze," shown in 1877, looked so alive that critics accused him of casting from a living body — an accusation counted as an insult to a sculptor, and in fact proof of how radical his method was.

"The Thinker" was first conceived in 1880 for the monumental "Gates of Hell," inspired by Dante's Inferno; it sat above the door as a poet-thinker figure surveying the human drama below. Rodin later enlarged it into an independent, monumental sculpture. The figure is wholly unlike the classical image of "thought": elbow on the opposite knee, back hunched, every muscle taut — thinking here is not a serene act but an effort that clenches the whole body.

Rodin's real revolution was in the surface. He did not erase the marks his fingers left while kneading the clay; the bronze surface is full of hollows and ridges, the light falling on it flickers constantly, and the sculpture seems to move even while standing still. This "unfinished"-looking surface was in fact a deliberate choice: instead of polished perfection, an honesty that shows the trace of the material and of the making hand.

Rodin founded no movement but is the starting point of modern sculpture; Brancusi, Giacometti, and those after them walked through the door he opened. Today original bronze casts stand in dozens of cities, foremost among them the Musée Rodin in Paris; as an object with no single original, reproducible, the sculpture also anticipates its age.