Alejandro Korn, (1860–1936) Tadeusz Kotarbiński, (1886–1981) Alexandre Koyre, (1892–1964) Karl Kraus, (1874–1936) Jiddu Krishnamurti, (1895–1986) Leopold Kronecker, (1823–1891) Richard Kroner, (1884–1974) Peter Kropotkin, (1842–1921) Kuki Shūzō, (1888–1941) L Antonio Labriola, (1843–1904) Jules Lachelier, (1832–1918) Pierre Laffitte, (1823–1903) Friedrich Albert Lange, (1828–1875) Susanne Langer, (1895–1985) Ferdinand Lassalle, (1825–1864) Peter Lavrovitch Lavrov, (1823–1900) Moritz Lazarus, (1824–1903) Edouard Louis Emmanuel Julien Le Roy, (1870–1954) Adrian LeMors, (1893–1956) Vladimir Lenin, (1870–1924) Konstantin Nikolaevich Leont'ev, (1831–1891) Jules Lequier, (1814–1862) Stanisław Leśniewski, (1886–1939) Lucien Lévy-Bruhl, (1857–1939) George Henry Lewes, (1817–1878) Kurt Lewin, (1890–1947) Clarence Irving Lewis, (1883–1964)* C. S. Lewis, (1898–1963) John Lewis, (1889–1976) Liang Qichao (or Liang Ch'i-ch'ao), (1873–1929) Liang Sou-ming, (1893–1988) Karol Libelt, (1807–1875) Israel Lipkin, (1810–1883)* Émile Littré, (1801–1881) Liu Shaoqi (orLiu Shao-ch'i), (1898–1969) Karl Nickerson Llywelyn, (1893–1962) Alain LeRoy Locke, (1886–1954) Alfred Loisy, (1857–1940) Jakob Lorber, (1800–1864) Aleksei Fedorovich Losev, (1893–1988) Nicholas Onufrievich Lossky, (1870–1965) Hermann Lotze, (1817–1881) Arthur O. Lovejoy, (1873–1962) Georg Lukács, (1885–1971) Jan Łukasiewicz, (1878–1956) Rosa Luxemburg, (1871–1919) M Mikhail Bakhtin, (1895–1975) Ernst Mach, (1838–1916) John Macmurray, (1891–1976) Philipp Mainländer, (1841–1876) Ernst Mally, (1879–1944) Karl Mannheim, (1893–1947) Henry Longueville Mansel, (1820–1871) Mao Zedong (or Mao Tse-tung), (1893–1976) Gabriel Marcel, (1887–1973) Herbert Marcuse, (1898–1979) Jacques Maritain, (1882–1973) Harriet Martineau, (1802–1876) James Martineau, (1805–1900) Karl Marx, (1818–1883) Tomáš Garrigue Masaryk, (1850–1937) Fritz Mauthner, (1849–1923) James Clerk Maxwell, (1831–1879)12 James McCosh, (1811–1894) William McDougall, (1871–1938) John Ellis McTaggart, (1866–1925) George Herbert Mead, (1863–1931) Georg Mehlis, (born 19th century) Friedrich Meinecke, (1862–1954) Alexius Meinong, (1853–1920)* Gregor Mendel, (1822–1884) Marcelino Menéndez y Pelayo, (1856–1912) Désiré-Joseph Mercier, (1851–1926) Franklin Merrell-Wolff, (1887–1985) Emile Meyerson, (1859–1933) Carlo Michelstaedter, (1887–1910) Nikolai Konstantinovich Mikhailovskii, (1842–1904) Miki Kiyoshi, (1897–1945) John Stuart Mill, (1806–1873) Ludwig von Mises, (1881–1973) William Mitchell, (1861–1962) Dimitrije Mitrinovic, (1887–1953) W. H. S. Monck (1839–1915) Maria Montessori (1870–1952) Addison Webster Moore, (1866–1930) G. E. Moore, (1873–1958) Gaetano Mosca, (1858–1941) John Henry Muirhead, (1855–1940) Max Müller, (1823–1900) N Paul Gerhard Natorp, (1854–1924) John Neihardt, (1881–1973) Leonard Nelson, (1882–1927) Otto Neurath, (1882–1945) John Henry Newman, (1801–1890) H. Richard Niebuhr, (1894–1962) Reinhold Niebuhr, (1892–1971) Friedrich Nietzsche, (1844–1900) Nishi Amane, (1829–1897) Nishida Kitaro, (1870–1945) Shalva Nutsubidze, (1888–1969) Anders Nygren, (1890–1978) O Georges Ohsawa, (1893–1966) Karl Olivecrona, (1897–1980) John Wood Oman, (1860–1939) José Ortega y Gasset, (1883–1955) Rudolf Otto, (1869–1937) P. D. Ouspensky, (1878–1947) P Vilfredo Pareto, (1848–1923) Giuseppe Peano, (1858–1932) Benjamin Peirce, (1809–1880) Charles Sanders Peirce, (1839–1914) Ralph Barton Perry, (1876–1957) Leon Petrazycki, (1867–1931) Jean Piaget, (1896–1980) Max Planck, (1858–1947) Georgi