  Worrall's position in his 1989 paper is not explicitly an epistemic one, and other comments suggest a different view: “On the structural realist view what Newton really discovered are the relationships between phenomena expressed in the mathematical equations of his theory” (1989, 122). If the continuity in scientific change is of “form or structure”, then perhaps we should abandon commitment to even the putative reference of theories to objects and properties, and account for the success of science in other terms. Others who have contributed to structural realism have more explicitly signalled a significant departure from traditional realist metaphysics. For example, Howard Stein: