Ah I see. My confusion comes from what is called multilayer perceptrons, which do have activation functions. Presumably that is done exactly because they don't

Ah I see. My confusion comes from what is called multilayer perceptrons, which do have activation functions. Presumably that is done exactly because they don't make sense without adding those. But that makes multilayer perceptrons different from ordinary perceptrons in more than just the multilayer part, which is very confusing.