Ralph Cudworth (1617 – 26 June 1688) was an English classicist, theologian and philosopher, a leading figure among the Cambridge Platonists. From a family background embedded in the early nonconformist environment of Emmanuel College in the University of Cambridge, where he studied, he became Regius Professor of Hebrew 1645-88, Master of Clare Hall 1645-54 and Master of Christ's College 1654-88. His great work, entitled The True Intellectual System of the Universe, was published in 1678. He was a leading opponent of Thomas Hobbes.