Epistemology is the study of knowledge. There are 3 types of knowledge.(1) Knowledge how—Example: Legolas knows how to shoot an arrow. (2) Knowledge by acquaintance—Example: Frodo knows Gandalf (3) Knowledge that—Example: Sauron knows that Frodo has the ring.
Most epistemology is the study of "knowledge that". In this context, the traditional definition of knowledge is justified, true, belief. I think that this definition is a good start in analyzing knowledge. I will define each of these aspects of knowledge.
Justification The state of being validated by proper means.
Truth The state that applies to propositions that accurately correspond to reality.
Belief A proposition that one accepts as being true.
If a belief is true and it is justified, then we say that a person has knowledge.
Example of not having knowledge: If the time is actually 12:00am and Ronald looks at a broken clock that is stuck on 12:00am and then Ronald believes that it is 12:00am, then Ronald has a belief that is true but is not justified. Therefore, we say that Ronald does not have knowledge because he did not gain his true belief by proper means. At least all 3 conditions must be met to consider whether or not someone has knowledge.
Example of having knowledge: If Lula witnesses a murder then she has knowledge that the murder happened because (1) Perceptions are a justified means, (2) the murder actually happened in reality and is therefore true, and (3) Lula believes that it happened.