Popper attacks the idea that what distinguishes science from non-science is the use of formal methods of observation. Why, in Popper's opinion, is

Popper attacks the idea that what distinguishes science from non-science is the use of formal methods of observation. Why, in Popper's opinion, is this criterion of demarcation unsatisfactory? How does the principle falsification provide, for Popper, a solution to the problem of distinguishing between scientific and non-scientific theories?