According to Bruce R. McConkie, then member of the Quorum of the Twelve Apostles of the LDS Church (June 1, 1980, in a fireside address at BYU):
Heresy one: There are those who say that God is progressing in knowledge and is learning new truths.
This is false–utterly, totally, and completely. There is not one sliver of truth in it. It grows out of a wholly twisted and incorrect view of the King Follett Sermon and of what is meant by eternal progression.
God progresses in the sense that his kingdoms increase and his dominions multiply–not in the sense that he learns new truths and discovers new laws. God is not a student. He is not a laboratory technician. He is not postulating new theories on the basis of past experiences. He has indeed graduated to that state of exaltation that consists of knowing all things and having all power.
The life that God lives is named eternal life. His name, one of them, is “Eternal,” using that word as a noun and not as an adjective, and he uses that name to identify the type of life that he lives. God’s life is eternal life, and eternal life is God’s life. They are one and the same. Eternal life is the reward we shall obtain if we believe and obey and walk uprightly before him. And eternal life consists of two things. It consists of life in the family unit, and, also, of inheriting, receiving, and possessing the fullness of the glory of the Father. Anyone who has each of these things is an inheritor and possessor of the greatest of all gifts of God, which is eternal life.
Eternal progression consists of living the kind of life God lives and of increasing in kingdoms and dominions everlastingly. Why anyone should suppose that an infinite and eternal being who has presided in our universe for almost 2,555,000,000 years, who made the sidereal heavens, whose creations are more numerous than the particles of the earth, and who is aware of the fall of every sparrow–why anyone would suppose that such a being has more to learn and new truths to discover in the laboratories of eternity is totally beyond my comprehension.
Will he one day learn something that will destroy the plan of salvation and turn man and the universe into an uncreated nothingness? Will he discover a better plan of salvation than the one he has already given to men in worlds without number?
The saving truth, as revealed to and taught, formally and officially, by the Prophet Joseph Smith in the Lectures on Faith is that God is omnipotent, omniscient, and omnipresent. He knows all things, he has all power, and he is everywhere present by the power of his Spirit. And unless we know and believe this doctrine we cannot gain faith unto life and salvation.
Joseph Smith also taught in the Lectures on Faith “that three things are necessary in order that any rational and intelligent being may exercise faith in God unto life and salvation.” These he named as–
1. The idea that he actually exists;
2. A correct idea of his character, perfections, and attributes; and
3. An actual knowledge that the course of life which he is pursuing is according to the divine will.
The attributes of God are given as knowledge, faith or power, justice, judgment, mercy, and truth. The perfections of God are named as “the perfections which belong to all of the attributes of his nature,” which is to say that God possesses and has all knowledge, all faith or power, all justice, all judgment, all mercy, and all truth. He is indeed the very embodiment and personification and source of all these attributes. Does anyone suppose that God can be more honest than he already is? Neither need any suppose there are truths he does not know or knowledge he does not possess.
Thus Joseph Smith taught, and these are his words:
Without the knowledge of all things, God would not be able to save any portion of his creatures; for it is by reason of the knowledge which he has of all things, from the beginning to the end, that enables him to give that understanding to his creatures by which they are made partakers of eternal life; and if it were not for the idea existing in the minds of men that God had all knowledge it would be impossible for them to exercise faith in him. [As quoted by Bruce R. McConkie in Mormon Doctrine (Salt Lake City: Bookcraft, 1966), p.264]
If God is just dabbling with a few truths he has already chanced to learn or experimenting with a few facts he has already discovered, we have no idea as to the real end and purpose of creation.