This post is belongs to a series of posts on Reality and Mormon theology.
The first 4 articles of faith of LDS theology logically depend on the previous article. Faith, repentance, baptism, and the gift of the Holy Ghost (Article 4) are brought about by the Atonement (Article 3) which was necessary because of our sinful nature and the fall of Adam (Article 2) which we must overcome to live again with Heavenly Father (Article 1).
If there were to be an even more basic article to precede article 1 what would it be? It would describe those things that are more basic than the God. What is more basic than the God? Reality with its eternal laws. God's power comes from his knowledge of these laws (D&C 93:36).
If LDS theology did have a zeroth article of faith then it would be something like: "We believe in reality (that existence exists)," or, "We believe in eternal laws," or, "We believe that reality has primacy over consciousness." This assumption distinguishes LDS theology from all other religious organizations in the world. self-evident axiom
But is their anything more basic than reality? No, the existence of reality is the most basic premise. All other beliefs ultimately rest on a belief in reality. It is a self-evident axiom. A belief is self-evident if one must assume the belief in order to try and deny it. Any argument trying to denying reality would be self-refuting. Axioms cannot be proven because "proof" is a concept that presupposes reality.