Philosopher, born, of Jewish parents, in a village of Minsk; came to Berlin, where he studied, lived an eccentric, vagabond life, dependent mostly on his friends; made the acquaintance of Kant and Goethe, and attempted and published an eclectic system of philosophy in 1790, being Kant's system supplemented from Spinoza, Leibnitz, and Locke, and even Hume; his last patron was Count Kalkreuth, at whose house in Siegersdorf he died (1754-1800).