We build our world on scientific knowledge, in fact we stake our lives on it. Every time we board a train, send an email or take a medical drug we reaffirm our trust in the products of science. But what, if anything, gives science the authority it seems to have? Is there a particular method that is distinctive of science? Can we distinguish science from pseudo-science? And how do the sciences generate and confirm theories from limited series of particular observations? Should we believe that the best-supported scientific theories and models are true, or should we merely accept that they 'work'? And what should our attitudes towards unobservable entities be? Finally, can science be a wholly neutral and objective mode of investigating reality? Or is it distorted by the values and interests of individual scientists and the societies they live in? And does that mean that its results must be understood in relation to the social, historical and ideological context in which it is carried out? The aim of this module is to introduce you to some of the basic problems, concepts and positions in the philosophy of science, and to encourage reflection on the power, and also the limitations, of scientific methods of thinking.