Editing Karl Popper (section)

=== Family and training ===
Karl Popper was born in [[Vienna]] (then in [[Austria-Hungary]]) in 1902 to [[Upper middle class|upper-middle-class]] parents. All of Popper's grandparents were [[Jewish assimilation|assimilated Jews]]; the Popper family converted to [[Lutheranism]] before he was born<ref name="TheFormativeYears" /><ref name="MageeStoryPhilosophy">[[Bryan Magee|Magee, Bryan]]. ''The Story of Philosophy.'' New York: [[DK Publishing]], 2001. p. 221, {{ISBN|078943511X}}</ref> and so he received a Lutheran baptism.{{sfn|Eichstätter}}<ref>Karl Popper: ''Kritischer Rationalismus und Verteidigung der offenen Gesellschaft.'' In Josef Rattner, Gerhard Danzer (Eds.): ''Europäisches Österreich: Literatur- und geistesgeschichtliche Essays über den Zeitraum 1800–1980'', p. 293</ref> His father, Simon Siegmund Carl Popper (1856–1932), was a lawyer from [[Bohemia]] and a doctor of law at the [[University of Vienna|Vienna University]]. His mother, Jenny Schiff (1864–1938), was an accomplished pianist of [[Silesians|Silesian]] and [[Hungarians|Hungarian]] descent. Popper's uncle was the Austrian philosopher [[Josef Popper-Lynkeus]]. After establishing themselves in Vienna, the Poppers made a rapid social climb in Viennese society, as Popper's father became a partner in the law firm of Vienna's liberal mayor [[Raimund Grübl]], and after Grübl's death in 1898 took over the business. Popper received his middle name after Raimund Grübl.<ref name="TheFormativeYears">Malachi Haim Hacohen. ''Karl Popper – The Formative Years, 1902–1945: Politics and Philosophy in Interwar Vienna.'' Cambridge: Cambridge University Press, 2001. pp. 10, 23, {{ISBN|0521470536}}</ref> (In his autobiography, Popper erroneously recalls that Grübl's first name was Carl).<ref>Karl R. Popper ([1976] 2002. ''[[Unended Quest: An Intellectual Autobiography]]'', [https://books.google.com/books?id=F_2WSLsDyvwC&pg=PA6 p. 6].</ref> His parents were close friends of [[Sigmund Freud]]'s sister Rosa Graf.<ref>''[[Wittgenstein's Poker]]'', page 76</ref> His father was a [[Bibliophilia|bibliophile]] who had 12,000–14,000 volumes in his personal library<ref name="bibliophile">Raphael, F. ''The Great Philosophers'' London: Phoenix, p. 447, {{ISBN|0753811367}}</ref> and took an interest in philosophy, the classics, and social and political issues.{{sfn|Thornton|2015}} Popper inherited both the library and the disposition from him.<ref>Manfred Lube: [https://web.archive.org/web/20070607075701/http://www.uni-klu.ac.at/ub/dokumente/Popper_Imprimatur.pdf Karl R. Popper – Die Bibliothek des Philosophen als Spiegel seines Lebens]. ''Imprimatur. Ein Jahrbuch für Bücherfreunde. Neue Folge Band 18'' (2003), S. 207–238, {{ISBN|3447047232}}.</ref> Later, he would describe the atmosphere of his upbringing as having been "decidedly bookish".{{sfn|Thornton|2015}}

Popper left school at the age of 16 and attended lectures in mathematics, physics, philosophy, psychology and the history of music as a guest student at the University of Vienna. In 1919, Popper became attracted by [[Marxism]] and subsequently joined the Association of Socialist School Students. He also became a member of the [[Social Democratic Party of Austria|Social Democratic Workers' Party of Austria]], which was at that time a party that fully adopted Marxism.{{sfn|Thornton|2015}} After the street battle in the Hörlgasse on 15 June 1919, when police shot eight of his unarmed party comrades, he turned away from what he saw as the philosopher [[Karl Marx]]'s [[historical materialism]], abandoned the ideology, and remained a supporter of [[social liberalism]] throughout his life.{{sfn|IEP Popper political}}

Popper worked in street construction for a short time but was unable to cope with the heavy labour. Continuing to attend university as a guest student, he started an apprenticeship as a cabinetmaker, which he completed as a journeyman. He was dreaming at that time of starting a daycare facility for children, for which he assumed the ability to make furniture might be useful. After that, he did voluntary service in one of [[psychoanalyst]] [[Alfred Adler]]'s clinics for children. In 1922, he did his [[matura]] by way of a second chance education and finally joined the university as an ordinary student. He completed his examination as an elementary teacher in 1924 and started working at an after-school care club for socially endangered children. In 1925, he went to the newly founded ''Pädagogisches Institut'' and continued studying philosophy and psychology. Around that time he started courting Josefine Anna Henninger, who later became his wife.

Popper and his wife had chosen not to have children because of the circumstances of war in the early years of their marriage. Popper commented that this "was perhaps a cowardly but in a way a right decision".{{sfn|Zerin|1998 |p=48}}

In 1928, Popper earned a doctorate in psychology, under the supervision of [[Karl Bühler]]—with [[Moritz Schlick]] being the second chair of the [[thesis committee]]. His dissertation was titled ''Zur Methodenfrage der Denkpsychologie'' (''On Questions of Method in the Psychology of Thinking'').{{sfn|Sturm|2012}} In 1929, he obtained an authorisation to teach mathematics and physics in secondary school and began doing so. He married his colleague Josefine Anna Henninger (1906–1985) in 1930. Fearing the rise of [[Nazism]] and the threat of the ''[[Anschluss]]'', he started to use the evenings and the nights to write his first book ''Die beiden Grundprobleme der Erkenntnistheorie'' (''The Two Fundamental Problems of the Theory of Knowledge''). He needed to publish a book to get an academic position in a country that was safe for people of Jewish descent. In the end, he did not publish the two-volume work; but instead, a condensed version with some new material, as ''Logik der Forschung'' (''[[The Logic of Scientific Discovery]]'') in 1934. Here, he criticised [[psychologism]], [[naturalism (philosophy)|naturalism]], [[inductivism]], and [[logical positivism]], and put forth his theory of potential [[falsifiability]] as the criterion demarcating science from non-science. In 1935 and 1936, he took unpaid leave to go to the United Kingdom for a study visit.<ref>[[A. C. Ewing]] was responsible for Karl Popper's 1936 invitation to [[University of Cambridge|Cambridge]] (Edmonds and Eidinow 2001, p. 67).</ref>