Editing Falsifiability (section)

==The elusive distinction between the logic of science and its applied methodology==

Popper distinguished between the logic of science and its applied ''methodology''.<ref name="cleardistinctioncomplete" group=upper-alpha/> For example, the falsifiability of Newton's law of gravitation, as defined by Popper, depends purely on the logical relation it has with a statement such as "The brick fell upwards when released".{{sfn|Chalmers|2013|p=62}}<ref name=appledancingexample group="upper-alpha"/> A brick that falls upwards would not alone falsify Newton's law of gravitation. The capacity to verify the absence of conditions such as a hidden string<ref name=invisiblestrings group="upper-alpha"/> attached to the brick is also needed for this state of affairs<ref name=Popperonstateofaffairs group="upper-alpha"/> to eventually falsify Newton's law of gravitation. However, these applied methodological considerations are irrelevant in falsifiability, because it is a logical criterion. The empirical requirement on the potential falsifier, also called the ''material requirement'',<ref name="thematerialrequirement" group="upper-alpha"/> is only that it is observable [[Intersubjective verifiability|inter-subjectively]] with existing technologies. There is no requirement that the potential falsifier can actually show the law to be false. The purely logical contradiction, together with the material requirement, are sufficient. The logical part consists of theories, statements, and their purely logical relationship together with this material requirement, which is needed for a connection with the methodological part.

The methodological part consists, in Popper's view, of informal rules, which are used to guess theories, accept observation statements as factual, etc. These include statistical tests: Popper is aware that observation statements are accepted with the help of statistical methods and that these involve methodological decisions.{{sfn|Popper|1959|loc=Sec. 68}} When this distinction is applied to the term "falsifiability", it corresponds to a distinction between two completely different meanings of the term. The same is true for the term "falsifiable". Popper said that he only uses "falsifiability" or "falsifiable" in reference to the logical side and that, when he refers to the methodological side, he speaks instead of "falsification" and its problems.<ref name="twomeanings" group=upper-alpha/>

Popper said that methodological problems require proposing methodological rules. For example, one such rule is that, if one refuses to go along with falsifications, then one has retired oneself from the game of science.{{sfn|Popper|1959|p=[{{Google book|id=0a5bLBbe_dMC|plainurl=yes|page=32}} 32]}} The logical side does not have such methodological problems, in particular with regard to the falsifiability of a theory, because basic statements are not required to be possible. Methodological rules are only needed in the context of actual falsifications.

So observations have two purposes in Popper's view. On the methodological side, observations can be used to show that a law is false, which Popper calls falsification. On the logical side, observations, which are purely logical constructions, do not show a law to be false, but contradict a law to show its falsifiability. Unlike falsifications and ''free from the problems of falsification'', these contradictions establish the value of the law, which may eventually be corroborated.

Popper wrote that an entire literature exists because this distinction between the logical aspect and the methodological aspect was not observed.<ref name="somecontradiction" group="upper-alpha"/> This is still seen in a more recent literature. For example, in their 2019 article ''Evidence based medicine as science'', Vere and Gibson wrote "[falsifiability has] been considered problematic because theories are not simply tested through falsification but in conjunction with auxiliary assumptions and background knowledge."<ref>{{Cite journal |last1=Vere |first1=Joseph |last2=Gibson |first2=Barry |date=2019 |title=Evidence-based medicine as science |url=https://onlinelibrary.wiley.com/doi/10.1111/jep.13090 |journal=Journal of Evaluation in Clinical Practice |language=en |volume=25 |issue=6 |pages=997–1002 |doi=10.1111/jep.13090 |pmid=30575209 |issn=1356-1294}}</ref>