Epistemology is the branch of philosophy that seeks to understand the nature and scope of knowledge. It focuses on the questions "What is knowledge?", "How do we come to know something?", "What do we know?", and "What is the justification for our beliefs?" Epistemology is concerned with the validity of our knowledge, the limits of our knowledge, and the sources of our knowledge. It looks at how knowledge is acquired, justified, used, and shared.