> I find it amusing how much closer Dijkstra's approach is to what might be called "normal" (Algol-ish) programming compared to the Abstract Nonsense[5] favored

> I find it amusing how much closer Dijkstra's approach is to what might be called "normal" (Algol-ish) programming compared to the Abstract Nonsense[5] favored by the category theorists. I wouldn't call it any less mathematical though. It's true that he mainly used a sequential, imperative notation for describing things, but it seems like later in his life, he preferred functional programming for teaching computer science to students. He petitioned the University of Texas to not switch from teaching it in Haskell to teaching it in Java for this reason. https://www.cs.utexas.edu/users/EWD/OtherDocs/To%20the%20Budget%20Council%20concerning%20Haskell.pdf https://www.cs.utexas.edu/users/EWD/OtherDocs/To%20the%20Bud... A fundamental reason for the preference is that functional programs are much more readily appreciated as mathematical objects than imperative ones, so that you can teach what rigorous reasoning about programs amounts to. The additional advantage of functional programming with “lazy evaluation” is that it provides an environment that discourages operational reasoning.