Contrast does not mean comparing two irrelevant issues or references, instead it urges us to visualize things through different perceptions and form an interrelated network to reinforce our interpretation of certain concepts and theories etc.
Both books describe the revolution of science. The 1st book refers to the terms of CS while the 2nd book describes it using variable examples and facts. However, both chapters are telling the same main point. The science evolves from experience and facts accumulated and gradually based on systematical learning. Learning is then divided by two categories; one is explanatory learning in the 1st book (normal science or paradigm in the 2nd book), the other being machine learning (paradigm theory predictions and fact gathering). The most significant difference between these two books is their terminology that is restricted by the writers’ research territory. While Leslie Valiant utilizes words like PAC and ecorithm as evolving algorithm, Thoma S. Kuhn stress more on the history and the development of electric and optic physics.