Plato was a Greek philosopher from 428/427 BC to 348/347 BC who was a student of Socrates and teacher of Aristotle. He emphasized critical thinking and questioning beliefs to arrive at truth. Some of Plato's most famous dialogues that explored philosophical ideas through conversations were The Republic, Symposium, Phaedo, Theaetetus, and Timaeus. Plato's philosophy focused on using reason to pursue knowledge and virtue for a good life. His ideas have significantly influenced Western philosophy.