KARL POPPER ON THE PROBLEM OF A THEORY OF SCIENTIFIC METHOD What are rules of scientific method and why do we need them? Can there be a theory of such rules, a methodology? Answers to these questions will largely depend upon one’s attitude to science. Positivists see empirical science as a system of statements which satisfies certain logical criteria such as meaningfulness or verifiability.   Popper sees the distinguishing characteristic of empirical statement as suscepitibility to revision (the fact that they can be criticized and superseded by better ones)

- deals with problem of induction in positivist philosophy of science - what is induction? passing from singular statements such as results of observations and experiments to universal statements such as hypothesis or theories. general universal statements whose truth or falsity can be arrived by means of systematic observation and experiment.   Popper criticizes inductive reasoning.

- for any conclusion drawn in this way may always turn out to be false; because we may observe thousands of white swans but this does not justify the conclusion that all swans are white. so how to establish the truth of the universal statements which are based on experience? need a logical principle of induction. but when we say logic we assume a higher order; a priori statement inductive reasoning can give us only probabilities, and probabilities are a priori as well.

Popper criticizes inductive reasoning. for any conclusion drawn in this way may always turn out to be false; because we may observe thousands of white swans but this does not justify the conclusion that all swans are white. so how to establish the truth of the universal statements which are based on experience?

so Popper offers deductive method of testing which means; hypothesis can only be empirically tested only after it has been created. distinction between psychology of knowledge (psychological) and logic of knowledge (epistemological) psychology of knowledge -- initial stage act of conceiving or inventing a theory logic of knowledge – analysis of scientific knowledge, questions of justification and validity, methods and results of examining it logically

deductive testing of theories - 4 lines: 1. internal consistency 2. not tautological 3. scientific advance over other theories empirical applications Tautology: Dependent and independent variables refer to the same construct  In a tautological argument, the evidence always supports the hypothesis. Example: socially excluded women are expected to have lower levels of education Ex: post-natal depression is more likely to be seen in women who gave birth recently

a positive decision can only temporarily support the theory, because subsequent negative decisions may always overthrow it. As long as a theory stands up to tests in the course of scientific progress we say that this theory is corroborated.

“ The aim of empirical method is not to save the lives of untenable theories, but on the contrary to select the one which is by comparison the fittest, by exposing them all to the fiercest struggle for survival.” Karl Popper 8 PSYC/SOCI 201 Spring 2011

Crucial test We need a crucial test to have a more credible hypothesis. Prior knowledge of politics------ better comprehension of news 1. Extended exposure to news  better comprehension of news 2. Personal involvement in politics better comprehension of news 3. Education  better comprehension of news 1,2,3 are alternative explanations of better comprehension of news. If I can reject 1,2, and 3, my hypothesis (H) will be more credible. I will have more support for hypothesis H.

SUMMARY: only falsifiable statements are scientific.   Popper’s concern was not to work out a logic of science, what science must be or what science is. It was “ what science ought to be” conception of science as something that grows. science is imperfect, fragmented and fallible. significance of science is not that it is true. we cannot know for sure that any general law is true. The significance of science is that we can move closer to the truth by correcting errors and inventing better theories. confirming or verifying a theory is biasing because we will always find confirming evidence because we are influenced by our theories. observations are theory-laden. selection and interpretation of facts in the light of our theory.