The ArgumentIn the controversy in 1989 over the reported achievement of cold nuclear fusion, parts of the physics and chemistry communities were opposed in both a theoretic and a professional competition. Physicists saw the chemists' announcement as an incursion into territory allocated to their own discipline and strove to restore the interdisciplinary boundaries that had previously held. The events that followed throw light on the manner in which scientists' knowledge claims and metascientific beliefs are affected by their membership of disciplinary (...) communities. In particular, the controversy offers evidence for a constructivist reinterpretation of the “division of nature into levels,” which is customarily held to underpin the division of science into disciplines. (shrink)