Nikolay Onufriyevich Lossky (Russian: Никола́й Ону́фриевич Ло́сский; December 6 [O.S. November 24] 1870 – January 24, 1965) was a Russian Orthodox Christian philosopher. His work expressed aspects of neo-idealism and metaphysical libertarianism from the Silver Age of Russian pre-Revolutionary and post-Revolution emigré philosophy, in what he termed intuitive-personalism, but deeply influenced by his conversion as an adult to Orthodox Christianity and his engagement with its influence in modern Russian thought. His book History of Russian Philosophy is a classic intellectual history of nineteenth- and early-to-mid-twentieth-century Russian philosophy from an Orthodox Christian perspective. His most famous students were his son Vladimir Lossky, an Orthodox theological writer, and the atheist-libertarian writer and Russian emigré Ayn Rand.
Born in Latvia to an Orthodox Christian father and a Catholic mother, he was expelled from school for promoting atheism. But shortly after the Russian Revolution, in 1918, after what he considered a miraculous escape from an elevator accident, he became an Orthodox Christian under the guidance of his friend and fellow philosopher Fr. Pavel Florensky.
Forced out of his university faculty position in St. Petersburg due to his Christian faith, he emigrated to Czechoslovakia at the invitation of Tomáš Masaryk, and as a professor at the Russian University of Prague in Bratislava became part of a vibrant network of ex-Marxist Russian Orthodox emigré intellectuals in Europe between the wars. After World War II he joined the faculty of St. Vladimir's Seminary, then in New York City, in America, and later moved to Paris where he died.
Drawing on German philosophical discourse with which he became engaged while working on his doctorate in Germany before World War I, he sought to articulate Orthodox Christian traditions of personhood, epistemology, and cosmology in the discourses of modern Western philosophy. His History of Russian Philosophy (1952) is an intellectual history of nineteenth- and early-to-mid-twentieth-century Russian philosophy. It includes a brief but in-depth survey of the philosophical works of Fr. Florensky and Fr. Sergius Bulgakov, examining in particular how the latter's sophic philosophy both drew on Orthodox traditions and came in part to obscure their ontological outlook. It also includes a summary of his own work and that of his son, Vladimir Lossy, and contrasts Soviet dialectical materialism with traditions of Russian philosophy rooted in Christianity.
Prof. Lossky's legacy includes the work of his son Vladimir Lossky, a prominent modern Orthodox theological writer, whose background in philosophy and Orthodoxy he helped to shape. His most famous university student, while he was still teaching in St. Petersburg after the Revolution, was the writer and atheist-libertarian philosopher Ayn Rand, who also became an emigré settling in America. She later appreciatively recalled the elder Lossky as the only one of her university professors in the newly communist Russia whom she remembered, for the influence of his teaching on classical philosophy on her work, but criticized what she considered to be his otherworldly Christian mysticism. (Despite the connection with Rand, and the classification of Lossky's philosophy as reflecting in part metaphysical libertarianism, his later political views after his rejection of Marxism and atheism have nonetheless been described as Fabian Socialist.)