Abstract. Donald MacKay has suggested that the logical concept of complementarity is needed to relate scientific and theological thinking. According to Ian Barbour, this concept should only be used within, not between, disciplines. This article therefore attempts to clarify that contrast from the standpoint of cognitive process. Thinking in terms of complementarity is explicated within a structuralist‐genetic, interactive‐constructivist, developmental theory of the neo‐ and post‐Piagetian kind, and its role in religious development is indicated. Adolescents'complementary views on Creation and on the corresponding scientific accounts serve as an illustration. After further analysis of parallel and circular complementarity, it is shown under which conditions complementarity of science and theology can be better justified and may be potentially more fruitful than is apparent from Barbour's or even MacKay's considerations. Copyright © 1990, Wiley Blackwell. All rights reserved
