I also found the examples confusing. What I got is they are all nouns (respect the grammar rule of having nouns for class names) but `PlanEvents` reads like data that is going to be processed (passive) whereas `EventPlanner` and `Scheduler` are concepts that process data (active). They have a verb: "plan" and "schedule".

I may be misreading, but I see these in the opposite way to throwaway41597 (https://news.ycombinator.com/item?id=9603427). To me, `PlanEvents` is active (it describes doing something, or, rather, commands to do it), whereas `EventPlanner` and `Scheduler` are passive (they describe the mechanism by which something is done, not the doing of it).

What’s not on the slide, but which I say during the talk, is that I’m making an analogy here between ‘Don’t use passive voice’ (English) and ‘use noun phrases for class names’ (object-oriented programming). Both are kinds of grammatical guidelines.

What I also say in the talk is that this analogy is a stretch, but at least advice from writers about writing can inspire us to think about how we write code.