Editing Pseudoscience (section)

===Falsifiability===
{{Main|Falsifiability}}
During the mid-20th century, the philosopher [[Karl Popper]] emphasized the criterion of [[falsifiability]] to distinguish [[science]] from [[non-science]].<ref name="Popper">{{cite book|last=Popper|first=Karl|author-link=Karl Popper|year=1959|title=The Logic of Scientific Discovery|isbn=978-0-415-27844-7|publisher=Routledge|title-link=The Logic of Scientific Discovery}} The German version is currently in print by Mohr Siebeck ({{ISBN|3-16-148410-X}}).</ref> [[proposition|Statements]], [[hypothesis|hypotheses]], or [[theory|theories]] have falsifiability or refutability if there is the inherent possibility that they can be proven [[False (logic)|false]], that is, if it is possible to conceive of an observation or an argument that negates them. Popper used [[astrology]] and [[psychoanalysis]] as examples of pseudoscience and Einstein's [[theory of relativity]] as an example of science. He subdivided non-science into philosophical, mathematical, mythological, religious and metaphysical formulations on one hand, and pseudoscientific formulations on the other.{{sfnp|Popper|1963|pp=43–86}}

Another example which shows the distinct need for a claim to be falsifiable was stated in [[Carl Sagan]]'s publication ''[[The Demon-Haunted World]]'' when he discusses an invisible [[dragon]] that he has in his garage. The point is made that there is no physical test to refute the claim of the presence of this dragon. Whatever test one thinks can be devised, there is a reason why it does not apply to the invisible dragon, so one can never prove that the initial claim is wrong. Sagan concludes; "Now, what's the difference between an invisible, incorporeal, floating dragon who spits heatless fire and no dragon at all?". He states that "your inability to invalidate my hypothesis is not at all the same thing as proving it true",{{sfnp|Sagan|1994|p=171}} once again explaining that even if such a claim were true, it would be outside the realm of [[science|scientific inquiry]].