Editing History of logic (section)

===Logic and psychology===
Between the work of Mill and Frege stretched half a century during which logic was widely treated as a descriptive science, an empirical study of the structure of reasoning, and thus essentially as a branch of [[psychology]].<ref>See e.g. [http://plato.stanford.edu/entries/psychologism Psychologism], Stanford Encyclopedia of Philosophy</ref> The German psychologist [[Wilhelm Wundt]], for example, discussed deriving "the logical from the psychological laws of thought", emphasizing that "psychological thinking is always the more comprehensive form of thinking."<ref>Wilhelm Wundt, ''Logik'' (1880–1883); quoted in Edmund Husserl, ''Logical Investigations,'' translated J. N. Findlay, Routledge, 2008, Volume 1, pp. 115–116.</ref> This view was widespread among German philosophers of the period:
* [[Theodor Lipps]] described logic as "a specific discipline of psychology".<ref>Theodor Lipps, ''Grundzüge der Logik'' (1893); quoted in Edmund Husserl, ''Logical Investigations,'' translated J. N. Findlay, Routledge, 2008, Volume 1, p. 40</ref>
* [[Christoph von Sigwart]] understood logical necessity as grounded in the individual's compulsion to think in a certain way.<ref>Christoph von Sigwart, ''Logik'' (1873–1878); quoted in Edmund Husserl, ''Logical Investigations,'' translated J. N. Findlay, Routledge, 2008, Volume 1, p. 51</ref>
* [[Benno Erdmann]] argued that "logical laws only hold within the limits of our thinking".<ref>Benno Erdmann, ''Logik'' (1892); quoted in Edmund Husserl, ''Logical Investigations,'' translated J. N. Findlay, Routledge, 2008, Volume 1, p. 96</ref>
Such was the dominant view of logic in the years following Mill's work.<ref>Dermot Moran, "Introduction"; Edmund Husserl, ''Logical Investigations,'' translated J. N. Findlay, Routledge, 2008, Volume 1, p. xxi</ref> This psychological approach to logic was rejected by [[Gottlob Frege]]. It was also subjected to an extended and destructive critique by [[Edmund Husserl]] in the first volume of his ''Logical Investigations'' (1900), an assault which has been described as "overwhelming".<ref>Michael Dummett, "Preface"; Edmund Husserl, ''Logical Investigations,'' translated J. N. Findlay, Routledge, 2008, Volume 1, p. xvii</ref> Husserl argued forcefully that grounding logic in psychological observations implied that all logical truths remained unproven, and that [[skepticism]] and [[relativism]] were unavoidable consequences.

Such criticisms did not immediately extirpate what is called "[[psychologism]]". For example, the American philosopher [[Josiah Royce]], while acknowledging the force of Husserl's critique, remained "unable to doubt" that progress in psychology would be accompanied by progress in logic, and vice versa.<ref>Josiah Royce, "Recent Logical Enquiries and their Psychological Bearings" (1902) in John J. McDermott (ed) ''The Basic Writings of Josiah Royce'' Volume 2, Fordham University Press, 2005, p. 661</ref>