1. Logical consistency—the claims of a belief system must logically cohere to each other and not contradict in any way. As an example, the end goal of Buddhism is to rid oneself of all desires. Yet, one must have a desire to rid oneself of all desires, which is a contradictory and illogical principle.
2. Empirical adequacy—is there evidence to support the belief system (whether the evidence is rational, externally evidential, etc.)? Naturally, it is only right to want proof for important claims being made so the assertions can be verified. For example, Mormons teach that Jesus visited North America. Yet there is absolutely no proof, archaeological or otherwise, to support such a claim.
3. Existential relevancy—the belief system should address the big questions of life described below and the teachings should be accurately reflected in the world in which we live. Christianity, for example, provides good answers for the large questions of life, but is sometimes questioned because of its claim of an all-good and powerful God who exists alongside a world filled with very real evil. Critics charge that such a thing violates the criteria of existential relevancy, although many good answers have been given to address the issue.