I'm an IT guy with an interest in systems thinking rather than a professional military officer, but it appears to me that Jomini and Clausewitz are looking at the same body of knowledge with the yin-yang approaches of synthesis and analysis. Both of them start at the point that there is this thing called "war", and attempt to define it. Clausewitz comes from the perspective of defining "war" synthetically, looking at this thing an trying to define key essences in terms of what "war" is, and how a state of war differs from the state of not-war (and recognizing that this state of not-war may be very different than what people conceive of as "peace", but that's a thought for a different day). Jomini seems to take the complementary approach of analysis, taking as more or less given that there is a thing called "war", and then defining it by its various features and functions, much as a physician would look at a body and separate it into a collection of constituent organs and tissues, each with distinctive features and functions. As the professor states in his conclusion, neither of these approaches is necessarily correct or incorrect, but each is a valid method of creating a model of the thing or phenomenon of "war". In systems theory, the definition of a model is a simplified description of a phenomenon that both describes and allows predictions to be made about the phenomenon (thing or system) being studied. By definition, a model is "wrong" in the sense that it simplifies the phenomenon, but it is hoped that the person using the model understands how the model is wrong, and that the model is "wrong" in a useful way.
Jomini's four principles of war are overly simplistic and ignore the effects of training, equipment, supply and morale. Based on Jomini's principles of war, the Zulus should have defeated the British garrison at Roarke's Drift and the Celts defeated the Romans at Alesia.
