A series of lectures organized in part by the Society for Applied Philosophy and entitled ‘Philosophy and Practice’ is presumably aimed at displaying the practical implications of philosophical doctrines and/or applying philosophical skills to practical questions. The topic of this paper, the role of interests in science, certainly meets the first condition. For as will be argued there are a number of theses concerning the role of interests in science which have considerable implications for how one should see the scientific enterprise in general and in particular for how one assesses the claim that science ought to be accorded its priviliged position in virtue of its results and/or methods And in view of the respect and resources accorded to science what could be of greater practical interest? It remains the case, however, that my interest may seem the inverse of that of the organizers of this series. For in looking at the role of interest in science, one is examining, so to speak, the extent to which the sphere of the practical determines what goes on in science. One is exploring ways in which the non-scientific impinges on the scientific. While my primary focus will be on the physical sciences, it will be argued that there is a significant difference between them and the social sciences; a difference which renders the social sciences intrinsically liable to penetration from outside. As will be seen, some of the particular arguments for this conclusion make pressing the question: what about philosophy? The answer, it will be concluded, is that philosophy is insulated from external influences to a considerable extent. In that lies both its importance and an explanation as to why much of it has little practical application.