1. Knowledge can be defined as a justified true belief, where justification is an essential component. However, counter-examples show that justification alone does not guarantee knowledge.
2. Different types of justification provide varying degrees of reliability in supporting a claim. Memory, sense perception, and logic may offer stronger justification than faith, authority, or intuition.
3. Justification is subjective, making a clear distinction between belief and knowledge challenging. While certainty is difficult to achieve, knowledge can be considered a strongly justified true belief.