The problem with the keystone analogy

arch“I told the brethren that the Book of Mormon was the most correct of any book on earth, and the keystone of our religion, and a man would get nearer to God by abiding by its precepts, than by any other book.” – Joseph Smith, emphasis added.

That Joseph Smith used the keystone as an analogy to the role the Book of Mormon plays in our religion is fine.  But the way Sunday School teachers tend to expound on that analogy is what I take exception with.  Here are some points I often hear in Sunday School:

  1. The keystone bears the weight of the entire arch.
  2. If you remove the keystone the whole arch will fall.
  3. You may be able to remove any other piece of the arch, and while it may look crooked, it may still stand.

This is one of those things where it sounds good, but if you stop to think about what you’re saying (or hearing), you’ll see that the opposite is true for each of these points.  We’ll take them one at a time.

arch diagram

First, the keystone (D) bears the least weight because it is on the top.  In this diagram, the stones labeled C bear the most weight.

Next, if you can imagine quickly removing the keystone (like whipping a tablecloth off a table with plates still on it), one can easily imagine that the two sides of the arch (B stones) would fall toward each other and stop each other’s fall.  So removing the keystone does not necessarily cause the arch to fall.

Finally, I can’t prove this, but imagine pulling out one of the lower B stones.  I’m pretty sure there’s no safe way (quickly pulling or otherwise) to remove the lower B stones without causing the whole structure to fall. 

So what are we left with?  Nothing from what I typically hear in Sunday School.  I’m sure there are remaining pieces of the keystone analogy that Joseph Smith had in mind when he said it.  Perhaps it’s that the keystone is at the center of the arch, or that a lot of weight from above the arch rests on the keystone.  Who knows?

Here’s another point to thinking before you repeat what you hear–especially if you are in a teaching setting.

2 Responses to “The problem with the keystone analogy”

  • Mitch says:

    I do agree that teachers tend to overuse and misuse quotes without understanding them fully.

    Check “Keystone” in Wikipedia. It says, “The term is used figuratively to refer to the central supporting element of a larger structure, such as a theory or an organization, without which the whole structure would collapse”. This is a quote from the Merriam Webster dictionary.

    I took a photo of the keystone at the Cove Fort entrance a couple of weeks ago. It is a very flat arch and if you removed this keystone the archway would definitely collapse. You can see two photos of the keystone at

  • Scott says:

    I am an early morning seminary teacher preparing to teach the Book of Mormon this year. I am looking at the keystone analogy and entertaining the idea of making an arch puzzle as an object lesson.
    I understand your complaint about how we often overanalyze such analogies, as if they themselves contain the doctrinal truths that they are made to illustrate.
    In the Church, we use a lot of building analogies: BoM as Keystone, D&C as Capstone, Christ as Cornerstone, etc. etc. All of them are important to the overall structure of the edifice, and as long as we realize that the Church isn't a literal building, that it is much more, using building metaphors to illustrate the importance of these different elements in the organization of the Church helps us to understand that all of the elements are needed for the structure to be sound, but some, like the Book of Mormon, are certainly more significant as weight-bearing elements of the Church.
    This is the approach I have chosen to take with my students as I discuss this analogy.
    Now, for something more mundane, where did you get your picture of the wood block arch? I am looking for a pattern that I can use to make one of my own. Any suggestions?