One of my greatest delights as a teacher is learning something new from my students. That happened today in my logic class, when Eli, Lily and I wandered down a rabbit trail of immediate inferences. We had used two immediate inferences to write a statement equivalent to some other statement, and realized that we could have gotten to that same answer using two different immediate inferences.  Eli asked if there was some “triangle of immediate inferences” that we could go through and end up where we started. After some playing around, we discovered, not a triangle, but what I will call The Square of Eli: Continue reading The Square of Eli →