A meta question. About applying a theory to itself. Can Popper's theory (methodology) of falsification be applied to his own work?
Suppose we found evidence that science advances by adopting non-falsifiable statements, wouldn't that prove that he was wrong? Maybe the statements themselves are not scientific, according to his standards, but maybe for the ones making the statement they are.
Popper's theories are part of the philosophical literature — a philosophy of science — not scientific works in their own right. Simple put, Popper's theories are not empirical studies; they are exercises in reasoned analysis as part of an effort to build a cohesive and coherent understanding of the nature of the activities we call 'science'. It's best to think of Popper as outlining a 'scientific ethic': a formula for how scientists ought to do their work, not a description of how they do do their work.
Yes, many people have argued that scientists do not think or act the way Popper suggests. That has had no more impact on Popperism than the idea that people don't regularly behave morally has had on Christianity.
The problem with Popper's theorizing is that he did not produce a coherent or consistent ethical framework. It was an interesting approach in its day (particularly in its proper role as an evolute of logical positivism), but it never got a proper handle on the demarkation issue — failing to properly distinguish between non-science, failed science, pseudoscience, and protocol-science — and never created a workable framework for those who wished to pursue science.
Yes, absolutely.
Popper developed a demarcation between science and pseudo-science, but he did not consider there to be a hard line between philosophy and science. Sciences instead were an outgrowth, a refinement, of particular specialty subjects within philosophy.
Therefore, the principle of falsification testing is one Popper himself applied vigorously to philosophy. Much of his own falsification work was aimed at logical positivism, and Popper was ultimately successful in replacing Positivism as the method of philosophy of science. He also worked to falsify materialist views of mind and of abstract objects -- reviving Frege's three world triplism as an alternative ontology.
Popper recognized the importance of taking the critiques of his own thinking seriously, devoted considerable effort in his later life to trying to address weaknesses other philosophers pointed out.
Notably, both Kuhn and Quine tested Popper's model, and found falsifications of it. Kuhn by noting the sociology of scientists does not follow Popper's model, and Quine by noting that falsification is impossible in principle, due to theory being underdetermined by evidence (all theories are infinitely patchable). Also, actual scientists do not abandon a theory at the first falsification, but instead modify one of its secondary associated assumptions. Popper's claim of science steadily approaching "truth", the principle of Versimilitude, was also shown to be computationally unstable.
In response to Quine, Popper recast falsification, to use a modified version of Occams Razor. Rather than simplicity, his version of Occam preferences the "more predictively powerful" of alternative theories that fit data. As the kluges that Quine's theorizing reveals are predictively weak, this pragmatic/modified version of falsification can replace the absolute one Popper had initially advocated for.
In response to scientists not abandoning theories when challenges are encountered, Popper constructed a theory of primary claims, and secondary assumptions. When the secondary assumptions get too kluged up, the primary theory loses its predictive power, thus falsification tests can, as they accumulate, lead to effective falsification of a theory.
Vs Kuhn, the consensus view is that Popper was articulating how science should be done, but scientists are human, so Kuhn was uncovering the irrational sociology among scientists.
This "testing" of Popper's claims -- lead to Popper eventually adopting more and more a pragmatic rather than analytical/logical approach to truth. His science approach is not ABSOLUTELY true, but with its pragmatic tweaks, it describes very well what scientists should do, and what they generally claim to be doing.
Extended from the original XKCD comic strip, which is in the frame.
I argue here that science is, what scientists do, as bound by the values of their community: Can one speak unambiguously of "The" Scientific Method?
Scientific knowledge is tentative, and I see trying to use Falsifiability on itself as implicitly taking a Foundationalist view of knowledge, the idea of an ultimate grounding of knowledge. But first that assumption hasn't been justified, and second it runs into insoluble contradictions: Does the first Godel's incompleteness theorem forbids the existence of a Theory of Everything?
I like David Deutsch picture in The Fabric of Reality, that when we try to assemble a picture of how we explain the world we need multiple modes of thinking. Briefly discussed here: Is it the job of physics to explain consciousness?
In principle, yes. The core of Popper's philosophy is that scientific results, scientific theories must be falsifiable. If they do not conform to this standard then it is no viable scientific theory.
This means that you simply have to find a theory that is not falsifiable.
You can say that these are not real scientific theories precisely because they do not conform to the standard of Popper, but then you overlook the fact that they are used by actual scientists.