section_path: Philosophy
section_name: Philosophy
paragraph_text: Philosophy
  
  Liberalism—both as a political current and an intellectual tradition—is mostly a modern phenomenon that started in the 17th century, although some liberal philosophical ideas had precursors in classical antiquity and Imperial China. The Roman Emperor Marcus Aurelius praised "the idea of a polity administered with regard to equal rights and equal freedom of speech, and the idea of a kingly government which respects most of all the freedom of the governed". Scholars have also recognised many principles familiar to contemporary liberals in the works of several Sophists and the Funeral Oration by Pericles. Liberal philosophy is the culmination of an extensive intellectual tradition that has examined and popularized some of the modern world's most important and controversial principles. Its immense scholarly output has been characterized as containing "richness and diversity", but that diversity often has meant that liberalism comes in different formulations and presents a challenge to anyone looking for a clear definition.