Sir Isaiah Berlin (1909-1997) was a Russian-British social and political theorist, philosopher, and historian of ideas. Born in Riga, Latvia, then part of the Russian Empire, his family moved to England in 1920. He was educated at St Paul's School in London and Corpus Christi College, Oxford. Berlin became a Fellow of All Souls College, Oxford, in 1932. During World War II, he worked for the British Diplomatic Service.
Berlin is known for his writings on political philosophy and the concept of liberty. His 1958 essay "Two Concepts of Liberty," where he distinguished between "negative freedom" (freedom from interference) and "positive freedom" (freedom to act), remains highly influential. Berlin's work explored the complexities of freedom and the potential clashes between different values. He was also known for his concept of "value pluralism," which posits that different moral values can be equally valid yet incompatible. He held various positions at Oxford University, including Chichele Professor of Social and Political Theory and president of Wolfson College. Berlin received many honors, including a knighthood in 1957 and the Order of Merit in 1971.