Theory in archaelogy has largely been an anglophone enterprise, and perhaps too inbred for its own good. The main French school, known particularly from the work of Alain Gallay and Jean-Claude Gardin, was well represented at a CNRS-NSF conference on 'Symbolic, structural and semiotic approaches in archaeology', held at Indiana University, Bloomington (IN) in October 1987, where a small group of American, British, French and Swiss archaeologists met to confront their theoretical views. Here Alain Gallay sets out the fundamentals of the 'logicist' position.