Abstract

The critical rationalism keeps apart the notions of rational behaviour and certainty, and explicitly admits our fallibility. This position seeks to avoid the risk of relativism assuming that there is an objective truth and that we can recognize and correct our mistakes. So it vindicates its right to evaluate the merits of rival theories and the need to eliminate those that were falsified. There are in the critical rationalism two different attitudes that will be called here “evaluative” and “prescriptive”. In this work I wish to defend the following thesis:1) The criticism that Feyerabend makes against the critical rationalism is bases on certain aspects of the evidence which affects not only to its prescriptive aim, but also to the evaluative task of methodology.2) It is possible to find an argument against prescriptivism that is independent of any consideration about evidence, avoiding in this way the undesirable consequences about evaluation.3) The notions of certainty and elimination are connected in a way that poses serious problems for the critical rationalism