While many claims have been made about the benefits of interdisciplinary approaches to science education, the contention is that little empirical data exist either to support or refute the claims. The demands of integrated approaches on students or teachers have not been subjected to either theoretical or empirical assessment. This paper presents a first step towards assessing the demands and considers the results of the assessment for the practice of interdisciplinary school science. The analysis is limited to the integration of natural sciences, history, and philosophy. In grades K through 6 or 9, the potential exists for the integrated study of natural sciences. However, from a content analysis of general science and social studies textbooks, topics are expressed serially and fail to expose students to the intellectual relationships among them. The history of science and philosophical foundations of science are poorly integrated in both science and social studies textbooks. In the analysis of tests, another reliable indicator of curriculum, there are few items that explicitly test for student understanding of the intellectual relationships among the natural sciences or their methods of inquiry. The paper discusses the historical case study approach, the problem/issue centered approach to integration, and pedagogical approaches to integration. The posited cognitive outcomes and cognitive demands of integration are presented. (Contains 62 references.) (PR)