Ernst Laas (June 16, 1837 – July 25, 1885) was a German positivist philosopher.

Laas was born in Fürstenwalde, Brandenburg, Prussia. He studied theology and philosophy under Friedrich Adolf Trendelenburg at the University of Berlin. In 1859, he completed a doctorate at Berlin with a thesis titled Das Moral-Prinzip des Aristoteles.

He became a professor of philosophy at the University of Strasbourg in 1872.^[1] In his Kants Analogien der Erfahrung (Kant's Analogies of Experiences, 1876) he keenly criticized Immanuel Kant's transcendentalism, and in his chief work Idealismus und Positivismus (Idealism and Positivism, 1879–1884, 3 volumes), he drew a clear contrast between Platonism, from which he derived transcendentalism, and positivism, of which he considered Protagoras the founder. Laas in reality was a disciple of David Hume. Throughout his philosophy he endeavours to connect metaphysics with ethics and the theory of education.^[2][3]

He died in Straßburg, Germany (now Strasbourg, France).

His chief educational works were Der deutsche Aufsatz in den ersten Gymnasialklassen (1868), and Der deutsche Unterricht auf höhern Lehranstalten (1872; 2nd ed. 1886). He contributed largely to the Vierteljahrsschrift für wissenschaftliche Philosophie (1880–82); the Literarischer Nachlass, a posthumous collection, was published at Vienna (1887).^[4]