The principal aspects of modern military theory derive from the outlook of the enlightenment period as well as the counter-cultural movement that followed, the German movement.
A former professional soldier, Clausewitz became a military theorist, developing theories about the art of war based on the battles of Frederick the Great and Napoleon. The result was his incredibly famous work, Vom Kriege (published posthumously in 1832).
Clauswitz’s originality is in his conception of war as a political and social phenomenon
Key points: war as a continuation of politics by other means, asymmetry between defense and offense, fog of war, trinity (blind natural force, chance and probability, 	subordination). (government, people, armed forces).

Enlightenment era military theory can be traced back to the 17th century professional soldier, Italian-born Raimondo Montecuccoli. His originality was the development of war theories as a science – to reduce experience to fundamental universal rules.  His vision would be the foundation for military thinkers of the enlightenment period.
In the 18th century, a dramatic upsurge of military literature emerged. The enlightenment period was particularly attached to the scientific aspect of intellectualism. For the great thinkers of that period, it was more about the capability of the human mind to master reality. The scientific model, for them, represented the ability (or method) to use reason and empiricism to lay a foundation for all human knowledge – military philosophy and theory included. Their beliefs were rooted in concepts such as universal knowledge, the ability to understand everything, and a passion for unveiling the ‘secrets’ of each discipline. They fantasized about making it math-like, as with Newtonian mechanics.
The enlightenment thinkers’ premise was that war was blinded by prejudices, filled with disorder and confusion. The ever-positivist thinkers sought to “scientize” it, establishing definitive rules and terms, with universal terms that would transcend historical circumstances.  They sought to transform the organization of  armies and conduct of war into a definite science. However, subsequent developments of the theory shifted into a more romantic view, highly iconic of that period, placing growing importance on the individual, the imagination and the genius. Thus the universal rules they attempted to establish ended up being circumstantially tied to the creative, genius general.
One prominent thinker of that period, De Saxe, describes war to us in an archetypical Enlightenment era fashion: a science covered in shadow, one without principles or rules.
Enlightenment military thinkers struggled primarily with one issue: reconciling their desire for universal, scientific rules, and the historical changes and circumstantial differences on the other.
The French enlightenment thinkers set the stage, followed by the later development in the German Aufklarung, which developed from the French model, but then rejected its intellectual premises – while still maintaining the ideal of pursuing a general theory of war.
Frederick the Great’s theories of war derived from those sources as well. He, too, sought to break down the theory of war into a science, an art to be studied professionally – and to that end he built military academies (officer schools primarily) throughout his kingdom.
Thus the writings of the Aufklarung thinkers, Nicolai and Zanthier, stressed the scientific nature of war, the need to systematize its study, and the necessity of military education. The 1770s saw a huge boom in the publication of military works.
British Side: Henry Llyod adapted the French school to the German theme.
Antoine Jomini: Connects enlightenment theories with Napoleonic warfare.  New focus of Napoleonic warfare: concentration of force.  Fusing it with Llyod’s rational of operations resulted in his own thing. VS Clausewitz: battles are not the only or decisive means of war, strategic operations with no battle have also historically achieved results. Principle: concentration of maximum force to achieve local superiority at the decisive point. Initiative and forced marches. Most important: skillful use of the line of operations. Maneuver around the enemy’s flank and destroy his communication. Central position and interior lines.
Clausewitz lead  an intellectual revolution against the traditional conception of military theory. Anti-enlightenment reactionary movement. Clausewitz argued fiercely that the conduct of war could not be reduced to universal principles. War was affected by innumerable factors, particularly political conditions and moral forces, filled with unknown and incalculable factors, and constantly changing.
Clausewitz laid the intellectual foundations for what would be the new German military school. The hegemony of that school was broken first by Berenhorst, then Clausewitz.  Under his teacher Scharnhorst’s tutelage, Clausewitz came to reject the systems established by the enlightenment era and learned from Scharhorst that theory had to be concrete and circumstantial, encompass the military and human conditions that form reality, and be linked to historical experience.
Clausewitz focused on the genius part of the enlightenment thinking. His works, contrary to those of Jomini, focused on the characteristic of the leader (Napoleon, Frederick). However, rules are not entirely worthless – they simply diminish in importance the higher level the level of warfare. At the tactics level, they are still relevant. But at the strategic level, the subjective factors and conscious decisions and thus the commander’s considerations play the decisive part.
In Clausewitz’s theory of war, however, the purpose of war is an all out crushing blow. Everything must be concentrated on amassing maximum power. The purpose is the destruction of the enemy forces, and the way to achieve that is almost exclusively through fighting.  Great battles and engagements lead to the greatest success.
However, Clausewitz’ historicism shows itself, pointing out that every period would have its own theory of war.

Differences between enlightenment and counter-enlightenment :
1)	Science: enlightenment says it’s simple, can be broken down and explain in universal terms.  World is governed by principles. Highly influenced by Newton. Counter-en says it’s way more complex and constantly in motion and changing.
2)	Experience: the counter focuses on man as a unique creature with his own experience. Rejects the tabula rasa notion.  Big focus on creativity and imagination.
3)	Movement towards historicism.
Jomini vs Clausewitz:
•	Jomini uses a very mathematical approach, despite claiming war is art
•	Clausewitz focuses on the psychological dynamics
•	War is where politics end, war is continuation of politics by other means
•	Jomini: what is the same in wars? Clausewitz: what is different between them?
•	Jomini: keep war controllable. Clausewitz: contain this uncontrollable phenomenon
New developments in war
 Enlightenment period: supply lines (growing army sizes), maps,
Clauswitz: Napoleonic warfare, growing scales, one power defeated all others, initiative, mobilization, rapid decision making
Events: 7 years war, Napoleonic wars,
Key words: Enlightenment rules and genius, counter-movement to French enlightenment and imperialism, Clausewitz and individualism, Counter-enlightenment (Isaiah Berlin) or Genen-Aufklarung (Nietzsche),  War as a social realm (rather than science or art), heavy focus on the nation-state, trinity of the army, people and government (and their relations), Criticism: state level focused (Martin van Creveld), descriptive vs guideline