The concept of “matrix” is central to group analysis, signifying, as it does, those supposed invisible but highly effective connections which bond persons, “a psychic network of communication which is the property of the group and is not only interpersonal but transpersonal” (Foulkes, 1968, p. 182). Foulkes extends the idea of the matrix to the “mother-soil” of the social unconscious, in which people are said to “share a fundamental, mental matrix (foundation matrix)” (Foulkes, 1973, p. 228). Two aspects of his views are of relevance to the current chapter; first, that the matrix is (usually) conceived in a positive manner, and, second, that it emphasises that which is shared and dis-emphasises those excluded and unincorporated elements who exist on another side, as it were, who stand on uncommon ground and who are thus seen as threats to the symbolic social body.