Following the Savior’s death, the Church He had established drifted into apostasy. Fulfilled were the words of Isaiah, who said, “The earth also is defiled under the inhabitants thereof; because they have transgressed the laws, changed the ordinance, broken the everlasting covenant”.
Realizing the importance of knowing the true nature of God, men had struggled to find a way to define Him. Learned clerics argued with one another. When Constantine became a Christian in the fourth century, he called together a great convocation of learned men with the hope that they could reach a conclusion of understanding concerning the true nature of Deity. All they reached was a compromise of various points of view.
The result was the Nicene Creed of A.D. 325. This and subsequent creeds have become the declaration of doctrine concerning the nature of Deity for most of Christianity ever since.
I have read them all a number of times. I cannot understand them. I think others cannot understand them. I am sure that the Lord also knew that many would not understand them.
And so in 1820, in that incomparable vision, the Father and the Son appeared to the boy Joseph. They spoke to him with words that were audible, and he spoke to Them. They could see. They could speak. They could hear. They were personal. They were of substance. They were not imaginary beings. They were beings tabernacled in flesh. And out of that experience has come our unique and true understanding of the nature of Deity.
President (1995-2008) Gordon B Hinckley CJCLDS
Understanding is a subtle thing, or maybe it is a very simple thing!
At any rate, the world is full of people who say they understand, who believe they understand - but apparently don't.
The human grasp of reason is so shaky, and human pragmatism so strong, that by and large people say and believe what is practically-expedient - and there are very very few (and in some times and places zero) people who do otherwise.
And some statements that claim to elucidate or explain are in reality un-understandable - and the people who understand most deeply know this.
(I am reminded of Einstein who knew that quantum theory was un-understandable, hence could not be regarded as a statement of reality. Many lesser minds, however, claim to understand it!)
I have often experienced the situation when I thought I understood something, but as learned and pondered more, I realized that I did not understand it and never had understood it - that I had been fooling myself (although I would have sworn in a court of law, or before God, that I did understand it - I had been mistaken).
This was the basis of most good science I have done - first the recognition that I did not understand what others claimed was clear and obvious and true; then finding an explanation that accounted for the primary observations and that I did understand.
What is the status of an un-understandable statement? Well, it can have many functions.
It may be the result of confusion, or an attempt to mislead.
In Christian history, an un-understandable statement may be a deliberately-crafted ambiguity whereby two or more intractably-warring factions read into the un-understandable statement what they seek, and each chooses to pretend they understand its meaning correctly.
More often the un-understandability is at the level of a non sequitur ("it does not follow") - several understandable statements placed side by side, but with no understandable link between them
Non sequitur is how the historical Christian church (more or less) 'solved' the vicious and intractable Christological ('nature of Christ') disputes of the early centuries - these disputes themselves being an artefact of the inflexible insistence of expressing Christian doctrine through philosophical spectacles manufactured to Classical Metaphysical specifications.
This technique of dispute resolution resulted in the usual mainstream formulations about the Holy Trinity being both One AND Three; and Jesus Christ having been both God and Man at the same time, despite that God and Man are being conceptualized as utterly different kinds of entity.
These things are stated very firmly, very solemnly, they are absolutely insisted upon and often made definitional of being-a-Christian - but they are un-understandable; they are unconnected statements placed side by side and claiming to make an argument - which allows what people really believe inside their heads (i.e what they actually picture or comprehend) to range very widely.
On the other hand, such non sequiturs may kill understanding, and faith, by placing un-understandability at the very heart of what Christians (supposedly) must believe.
For some, this is intolerable - they need to understand the most important things; rather than having the most important things expressed in forms that are intrinsically un-understandable.
In reality such 'understanding' as comes from the non sequitur is more of the nature of a truce, or an agreement to go no further along that line of argument.
That is understandable, and it may be expedient in situations of intractable conflict - but it is also hazardous, spiritually - and leads to those in authority solemnly insisting upon solemn non-sense (i.e. intrinsically un-understandable statements), and allowing a kind of dishonesty into the very heart of Christianity.
For me, one of the most wonderful aspects of Joseph Smith's Restoration of Christianity was his work in putting clear, comprehensible explanations back at the very heart of Christian doctrine - in clearing-out the major non sequiturs.
Of course, its honesty, clarity and understandability exposed Mormon doctrine to ridicule; but Christianity is indeed intrinsically absurd (or blasphemous) to those who do not believe it (hence the temptation to hide its absurdities by retreating into abstraction and un-understandable non sequitur - whether or not re-framed as 'mystery').
I believe that humans are incapable of a metaphysical system which is both sufficiently concrete and commonsensical to be understandable, and yet also comprehensive.
All comprehensible metaphysical systems therefore run into problems (e.g. infinities of regress, zeroes, stasis) when pushed further than explaining the appearances.
But I think it reasonable to prefer a system which solves the up-front and core problems of Christianity - and these are the Christology problems.
And they were solved by Joseph Smith - by means of chucking-out the philosophical (specifically metaphysical) presuppositions of Classical Theology. This 'move' would perhaps not have been acceptable in the early centuries of the Church, but it is acceptable now.
To solve the Christology problems, it is necessary to understand God the Father, Jesus Christ, and Man in a way which makes understandable that Christ could be both God and Man - this Joseph Smith achieved, by recognizing (taking literally the Biblical descriptions) that God, Christ and Man are qualitatively of the same kind, despite truly-vast quantitative disparities.
And this was a great achievement, greatly valued by those who benefit from it.
But I expect that the whole thing started with Joseph Smith knowing that he did not understand the existing explanations of Christianity, and refusing to accept proffered explanations that he did not understand.