" It was these Prussian schools that introduced many of the features we now take for granted. There was teaching by year group rather than by ability, which made sense if the aim was to produce military recruits rather than rounded citizens. There was formal pedagogy, in which children sat at rows of desks in front of standing teachers, rather than, say, walking around together in the ancient Greek fashion. There was the set school day, punctuated by the ringing of bells. There was a predetermined syllabus, rather than open-ended learning. There was the habit of doing several subjects in one day, rather than sticking to one subject for more than a day. These features make sense, argues Davies, if you wish to mould people into suitable recruits for a conscript army to fight Napoleon. "

― Matt Ridley , The Evolution of Everything: How New Ideas Emerge