This year is the 50th anniversary of the publication of the final volume of Francis Sears’s three‐volumePrinciplesofPhysics. This text, which was very successful, marked the beginning of a new type of introductory physics course. A comparison is carried out betweenPrinciplesofPhysicsand an older text,Physicsby Hausmann and Slack. It is argued that the two texts represent different views of physics. An attempt is made to draw lessons concerning the conditions required for a radical change in the introductory course.