lambda-term See COMBINATORY LOGIC, LAMBDA -. CALCULU. Lambert, Johann Heinrich (1728–77), German natural philosopher, logician, mathematician, and astronomer. Born in Mulhouse (Alsace), he was an autodidact who became a prominent member of the Munich Academy (1759) and the Berlin Academy (1764). He made significant discoveries in physics and mathematics. His most important philosophical works were Neues Organon (‘New Organon, or Thoughts on the Investigation and Induction of Truth and the Distinction Between Error and Appearances,’ 1764) and Anlage zur Architectonic (‘Plan of an Architectonic, or Theory of the Simple and Primary Elements in Philosophical and Mathematical Knowledge,’ 1771). Lambert attempted to revise metaphysics. Arguing against both German rationalism and British empiricism, he opted for a form of phenomenalism similar to that of Kant and Tetens. Like his two contemporaries, he believed that the mind contains a number of basic concepts and principles that make knowledge possible. The philosopher’s task is twofold: first, these fundamental concepts and principles have to be analyzed; second, the truths of science have to be derived from them. In his own attempt at accomplishing this, Lambert tended more toward Leibniz than Locke. M.K.