Men and brethren,
The parable of the kinetochores: Your genes are composed of DNA. Each of your cells has a full complement of this information stored on 46 chromosomes. When it comes time for a cell to divide, the DNA is replicated and a copy of each chromosome is made, and the copies stick together (ie two copies of chromosome 22 from your mother, called sister chromatids). As the cell divides it needs to decide what chromosomes to put where so that each daughter cell receives the right DNA. This process is called mitosis. The mechanism involves the attachment of cables to the "kinetochore" of each chromosome pair. Now each kinetochore has to be bound to cables from both poles of the dividing cell, such that the pair of chromosomes is put under tension. The tension eventually rips apart the pair such that one copy of each chromosome moves to each pole, and the poles separate into the new cells. Cells have complicated machinery to ensure that without this tension cell division stops, for without it there is no way to ensure that the pairs separate to the new cells correctly. He who hath ears to hear let him hear.
I know what you're thinking. "I just read a whole paragraph of cell biology I've tried to forget since high school, and for what!?" For the tension, the balance. Often I think the tension is crucial to our development and further growth. It provides a stable, balanced state that can adjust rapidly to changes in equilibrium. There are many such tensions crucial to Mormonism. Lehi may have something like this in mind with his classic 2 Nephi 2:11 assertion that there must be opposition in all things, and if not there is no good, no life, no sense, no purpose, nothing. Later in verse 27 he states that we are free to choose liberty and life through the great mediator or captivity and death from the devil. Note that we are not free from influence, but only to choose how the tension will affect us.
This works for tension between two good things also; consider for example the tension between justice and mercy. After working for months to live the rules and get my sorry behind up at 5:30 to study, I finally developed a meaningful morning schedule in Japan. I loved the quiet and the time to meditate, study, and be close to the Lord. Then I get a companion who sleeps in, is a raving lunatic, and makes this peaceful serenity all but impossible. The Just side of me wants to make him live by the same rules, to hold justice over his head. Now is justice bad? I need to reinforce it to myself so that I can make myself keep doing what I know to be right, and what I really desire to do. But I also need to show mercy to the companion and really understand him and develop love for him unconditionally. The tension of the law for oneself but love for others not following that law is very severe sometimes. Yet it set up situations where my 'heartstrings' could be stretched, rearranged, set up correctly, so that I could develop the humility and charity to do right and still love right.
I suggest that the tension between evangelism and hyper-pluralism is the same situation. We need a fixed point to believe in--a necessary group of ordinances for salvation. We also need to have respect and interest and genuine love for those who do not believe as we do. But if we operate only at these poles we will be ineffective at best. But the combination of these two points pulling at us can produce tensions that can make us productive: with purpose, faith, and tolerance. The either/or is a false dichotomy. In my experience the tension has again torn down pride and increased love, but that is not always the response. I do believe that the tension and experience is necessary, though not sufficient. Without the willingness to have a broken heart and contrite spirit, you can choose to harden your heart to the tension (and that is tempting, it is not a pleasant process).
Alternatively think of the tensions we talked about between an individual epistemology in mormonism--confirmation of the spirit--vs the authoritarian structure of the institution and the priesthood. (Contrast the jewish version of a rigid epistemology defined by strict readings of canonical text, with a lack of institutional structure). The paradox in mormonism seems to be that you can receive any revelation you want, as long as its what the prophet has already said. This seems to be the tension that Sam was referring to last week in elders quorum when he talked about the two kinds of faith: individually praying and receiving spiritual confirmation on a matter vs. following what the leaders have said. Intellectuals like to emphasize the knowing for yourself kind, and leaders like to emphasize the latter. But in the limit of either pole things fall apart. Either we have a group (much like the early christians) that becomes increasingly diverse and in the language of D&C 1 walk in the image of their own god, or we get a fascist authoritarian state. But with both, we can form a unified coherent group and grow closer to God. We believe that the prophet speaks truths that we can know for ourselves. Amazing as it is, that faith makes the tension do work for us.
Now the literary critic would like to emphasize hyperpluralism, and I would tend to be absolutist. I recognize the importance of pluralism and tolerance, and can see the dangers in oversimplification of the message and over-centralization institutionally, as well as on a personal level the dangers of intolerance and lack of love. I want to argue for the balance, not for strict absolutism. But in the bastion of liberal academia that is our little red brick schoolhouse, it may be harder to remember why absolutism is worthwhile or defensible. Let me refer to Moroni 7: Mormon writes that all good things come from God and evil from the devil (ah, yes, the poles). He then writes that the spirit of Christ, or light of Christ, is given to all to know good from evil. Our goal is to lay hold of every good thing by choosing the good and clasping it. Note it says every good thing... a pluralist idea and one that Joseph emphasized. How do we do this Mormon asks? By faith--by acting on what we think the good is, by being positive and clinging to the good things. Faith to me is a very active concept, not just a passive unjustified belief. Mormon emphasizes that we need to have the word of God preached to us to further develop our faith (here the necessity of prophets, leaders, authority etc). So I believe people who develop faith in this life who are not Mormon will have developed it according to these principles but on the good in their own law and tradition, not on ours. But since God is the author of all good things, they will continue in their faith to the further light and knowledge they will receive in the hereafter. I don't think this is any more problematic (contra Dennis Potter) than is the idea that if we pray about the prophet's teachings or the Book of Mormon we can get a spiritual confirmation for ourselves (see Sam's tension above). We just don't know enough about the situation in the spirit world, but have to have faith that everyone will indeed be given a fair chance.
My tension image is probably similar to Eugene England's idea of paradox and dialogue, and emphasizes that both sides are necessary and in many cases both sides are good. It is dangerous sometimes in that we can talk past each other. But the balancing of these tensions is key.