Changes

|Prehistory=Logical positivists were concerned with justifying scientific knowledge and progress. In their case, it was about increasing the probabilities. As a consequence, they believed that a theory of scientific change should be normative. After all, the actual scientific practices may concern many changes in belief that were not justified on epistemic grounds.  Likewise, Popper believed that his theories were meant to be normative and he did not focus on studying the actual examples of science. However, both group occasionally employed examples from the history of science to persuade other philosophers. For instance, Popper used Eddington’s confirmation of Einstein’s theory to illustrate his concept of crucial experiments. Lakatos distinguished between internal and external history of science. The latter is concerned with what actually happened during an episode of scientific change while the former is about justifying the scientific change on grounds that are epistemically acceptable. Internal history of science is about reconstructing a scientific episode and justifying it by using the normative theories we possess.  After the Structure of Scientific Revolutions was published, Kuhn changed the view of the entire field. He showed that many of the scientific changes were completely different from the normative philosophical views of how good science ought to be conducted. This led to a disenchantment over the normative theories due to the fact that it they were not justifying the actual science as it is conducted. Given that the main reason for normative justification of various scientific practices was justifying the epistemic authority of science, philosophers of science began accepting that the actual practice of science should be the starting point of philosophical theories.    One of the reasons why the classic philosophy of science failed to accomplish its task was the vagueness of its position regarding this question. The theories of Popper, Kuhn, Lakatos, and early Laudan can all be considered either as descriptions of how science changes through time and/or prescriptions of how it ought to change.[[CiteRef::Barseghyan (2015)|pp. 12-21]]