The paper analyzes which is the proper role of history of science in philosophy of science. I argue that, traditionally, philosophy of science has focused on the normative dimension of science. Several positions within philosophy of science stem from different perspectives on such dimension. I classify them according to two variables (descriptivism/prescriptivism, and historicism/non-historicism). Then I discuss the role of history of science within all these four alternatives. I conclude that: (1) philosophers and historians pursue not only different, but opposite aims; (2) historical evidence is useful for assessing the relation between methods and results; besides this, only very simple or radical philosophical views can be ¿refuted¿ by historical evidence; (3) the disagreement between those who think that history of science is necessary for philosophy of science and those who think it is not is, in fact, a disagreement about the prospects for a general theory of science; (4) such disagreement cannot be resolved appealing to historical evidence; if it can be resolved, philosophical arguments should somehow be invoked.