Hume, an epistemologist, questioned the logical justification of universal statements about reality. These questions about the value of induction created a dilemma for Hume. As a positivist, he sought knowledge as derived from the observable. However, he reduced the metaphysical to nonsense and hence found problems with the inductive method. The inconsistencies Hume discovered in the principle of induction—that it is impossible to show the validity of natural laws by observation or experiment—may be addressed by demarcation according to Popper.
The Logic of Scientific Discovery