1. Coherence Theory (Theory of Coherence)
Based on this theory, a knowledge considered to be true if the knowledge kehoren with the knowledge that exists and has been proven to be true. In the study of mathematics this is usually called the deductive nature.
2. Correspondence Theory (Theory of corespondence)
Based on this theory, a knowledge considered to be true if the knowledge of having a relationship with a reality that is true. This theory is based on the empirical fact that knowledge is true if there are facts that support that is true knowledge. Thus the truth here is based on inductive inference.
3. Pragmatic Theory (Theory of Pragmatism)
According to this theory, knowledge is said to be true if the knowledge is seen practically completely or have properties that true practicality. Followers of this theory argue that knowledge is true if it has keguanaan practical.