Diagramming sentences: “pretty” equals “predicate adjective.”

I love diagramming sentences.  When learning grammar, it’s a great alternative to the traditional way of labeling and describing parts of speech and sentence structure.  But the trouble with diagramming, as many in my life have been quick to point out, is that you can diagram a grammatically incorrect sentence.  And so for that reason, it is a flawed teaching tool.  I suppose.  Just because you put a slash in front of a word and call it an “adjective,” that does  not make it equal to an adjective.

In my parallel-universe-math-class, we are learning how to solve linear equations, which means finding the point(s) at which various lines intersect on a graph.  The intersection is the solution.  If there is no intersection, there is no solution.  If you graph the lines, you can see there is no intersection.  But if you’re working with formulas to find the solution, you end up with an inequality–for example, “0 = 26”–that you then call “false.”  Everyone knows that 0 does not equal 26, and just because you put an equal sign in between two numbers does not make them equal.

Solving a linear equation with substitution: “0” does not equal “26.”

I feel especially sensitive to this because this semester it has taken me (is still taking me) so long to understand how to solve equations, and I frequently end up with mathematical gibberish.  The assumption that I can look at “0 = 26” and “know” that it is false is, itself, flawed.

What do you do when you meet someone who doesn’t share the foundational knowledge that lets them know when something is or is not equal to something else?  And related, what do you do when that someone does not want to acknowledge that they have created a false equality?  And in these general terms, can we then go from diagramming –> to linear equations –> to hashtags and pithy memes?  How do you explain to someone that #BlackLivesMatter does not equal #AllLivesMatter, despite the structural similarity and the simple swapping of adjectives? How do you explain that gender neutral bathrooms do not equal the rape of your daughter? That religious freedom laws do not equal nondiscrimination laws?

Here’s where I end up:

• In the grammar world, inequality can be a reason not to use a teaching tool, but this is because many grammarians acknowledge that not everyone recognizes inequalities when we see them.
• In the math world, inequality can be just one of many outcomes, and it is a way to learn something about the problem at hand. “No solution” means something.
• In the real world, how can we reconcile these two approaches when it comes to inequality in our communities?  There seems to be no (easy) solution.