What Is Karl Raimund Popper’s Philosophy of Science?June 27, 2021
His view of the scientific method is based on falsifying every theory in order to “put all systems through a rigorous test and eventually choose the relatively favorable system”; because, according to Popper, theories can never be empirically verified because of the invalidity of the principle of induction; but it can be wrong.
The “Failability Principle” is the foundation of Popper’s theory of science.
So, for a theory to be scientific, it must be falsifiable. Popper was interested in Einstein’s theory of relativity, Marx’s understanding of history, Freud’s theory of psychoanalysis, and Alfred Adler’s theories of individual psychology. In particular, an approach put forward by Einstein’s theory (light rays passing near the sun undergo bending under the influence of the sun’s gravitational field) impressed Popper when it was confirmed during the 1919 solar eclipse. It was not that the prophecy of the theory turned out to be correct that impressed Popper. If the premise proved untrue, the theory that would have been falsified would be immediately rejected.
The important thing was that the theory was formulated in a way that was open to falsification. Popper pointed out that the owners of other theories (Marx, Freud, Adler) did not specify under what conditions they would give up their theories. These theories, which had many confirmatory but uncertain falsifiers, were unscientific, according to him. Popper, no matter what theory, it is easy to find empirical support under certain conditions; scientificity was not based on providing empirical support, but on determining under what conditions the theory was wrong. If a theory is falsifiable, it is scientific. Karl Popper said that the best theory is “the one that can be falsified and refuted over time”.
Development of Scientific Knowledge
According to Popper: “The central problem of epistemology, which has always been and still is, is the problem of the development of knowledge. And the development of knowledge can best be studied by investigating the development of scientific knowledge.” (Popper, 1965:15)
An example explaining the development of knowledge in Popper can be found in Magee’s book entitled “Philosophy of Science and Political Theory” by Karl Popper.
“Let’s say we start by believing that it is a scientific law that water boils at 100 degrees Celsius, as our child is taught in school. No matter how many confirmatory cases there are, it is not enough to prove it; but we can test it by looking for cases where it is not valid. (…) If we exercise our imaginations enough. , we soon discover that water does not boil at 100 degrees Celsius in closed vessels. Thus, it turns out that what we thought was a scientific law is not. Now, at this point, we can go astray and try to salvage our initial premise by narrowing it down to the empiricist content. After that, we have a systematic way of refuting our third proposition. We can start the venture. And so on.” (Magee, 1993:22)
Of course, our example should not continue like this; because, as seen in the previous chapter, science seeks more content, not less. We must then develop another theory that can explain the handicap of the first in the case of falsification. For example; we should ask ourselves. It goes on like this: “It increases our knowledge and restarts our search for a better theory.” (Magee, 1993:23)
To cite an example of this from Popper, it can be said that “Kepler’s and Galileo’s theories were unified and surpassed by Newton’s logically stronger and better testable theory, and similarly, Fresnel’s and Faraday’s were also supplanted by Maxwell’s theory. It was surpassed by Newton’s and Maxwell’s (…) by Einstein. In each case, progress was towards more informative and therefore less probable theories (Popper, 1963b:220).
An important point here is not to resort to ad hoc  changes when modifying the theory. So these changes should also be testable.
“Some truly testable theories may continue to be defended by their admirers after they have been tested and found to be wrong—for example, by introducing an ad hoc auxiliary hypothesis, or by being reinterpreted again ad hoc so that the whole theory is missed without refutation. Then I described it as ‘compromising distortion’ or ‘compromising trickery’.” (Popper, 1996a:170)
 An example might explain this: “This is indeed an example based on an encounter between Galileo and an Aristotelian adversary in the early seventeenth century. Since Galileo carefully observed the moon through his newly invented telescope, the moon is not a smooth sphere but full of mountains and craters. (…) But observations threatened a fundamental Aristotelian notion. Galileo’s opponent defended his theory against blatant falsification, which was blatantly ad hoc. He claimed that there was an invisible substance that filled the mountains and covered the mountains” (Chalmers, 1990: 102)