ABSTRACT This essay presents a historical epistemology of the nineteenth‐century controversy concerning a scientific hoax, the Cardiff giant. My focus is on the shifting meanings given to the giant, which were based on epistemologies derived from scientific authority, religious belief, and market relations. In 1869 a farmer in Cardiff, New York, claimed to have discovered the fossilized remains of a prehistoric, perhaps biblical, giant on his property. While some scientists stressed the need to cooperate with commercial showmen, enthusiasm for the (...) giant incited the ire of others, who sought to debunk it and the culture that sustained it. Drawing on local newspaper reports, memoirs, nineteenth‐century exposés, and publicity materials associated with the giant’s display, I link the episode to the history of popular and scientific observation. The giant was a particularly troubling spectacle because as an object of inquiry it blurred the modern boundaries separating nature, society, and religion. (shrink)