Karl Popper's Falsification was formulated in the early half of the 1900's when there were many theories claiming to be scientific. Some of these included Einstein's theory of relativity, Freud's psychoanalysis, Adler's Individual psychology, and Marxism. Popper, after studying these theories began to perceive a problem. The problem was called demarcation, and its question was what criteria distinguish real science from pseudo-science. Popper found a solution to this problem by looking at the theories in question. What he noticed was that in Einstein's theory of relativity there were clear observations, such as light not bending, that if seen would expose his theory as being false. This was unlike the rest of the theories that seemed to find confirmations everywhere and be able to explain anything. Popper found this power of explanation, which seemed at first very forceful and compelling, was actually their greatest weakness. With these thoughts in mind Popper had come up with an answer to the problem of demarcation, he called it falsification. .
Popper said that real science follows a falsification method, and does not practice conventionalism. He said scientists formulate theories that are falsifiable. They then subject their theories to severe tests in an effort to show them false, they do not try to confirm them. Based on their theories, scientists can derive predictions that are bold and are such that they will likely be false if the theory tested is false. This method is a contrast popper says to the pseudo-sciences that don't subject theories to sever tests and try instead to confirm their theories true when ever possible. Pseudo-science also forms wimpy predictions that will likely be seen as true even if the theories are wildly false. .
Besides debating real science versus pseudo-science Popper goes a step further in explaining how his method works in real science as a prediction is tested.