The ancient Greek philosopher known for his contributions to ethics and epistemology is Socrates. His approach to philosophy emphasized the importance of questioning and dialogue, famously encapsulated in the Socratic method, which involves asking probing questions to stimulate critical thinking. Socrates did not leave written records; instead, his teachings were documented by his students, such as Plato. His ideas formed the foundation for Western philosophy, and his emphasis on self-knowledge and ethical living continues to influence modern philosophical thought.