A Revolution in Military Ideas: The Continuing Importance of the Enlightenment in an Age of Technological Autonomy

December 09, 2019
A Revolution in Military Ideas: The Continuing Importance of the Enlightenment in an Age of Technological Autonomy
A Revolution in Military Ideas: The Continuing Importance of the Enlightenment in an Age of Technological Autonomy
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“War is the father of all, king of all. Some it makes gods, some it makes men, some it makes slaves, some free.”
—Heraclitus of Ephesus[1]

Approximately 2500 years ago, Heraclitus of Ephesus outlined war’s evolutionary power to highlight its value for mankind and society as an engine of progress. The conduct of war, as well as the military itself, is shaped first and foremost by the perception of responsibility more so than technology. It was the responsibility for the impact of military actions that directed mankind to create a legal framework to wage war and created the requirement to direct military power professionally. Humans have repeatedly hidden from responsibility in war behind the question of loyalty either towards god, a head of state, or technology; yet we remain accountable for the outcomes of destructive force. War is a social phenomenon. The employment of military power remains an expression of a society’s values and, therefore, our responsibility. This article intends to argue that, in addition to the above, the Enlightenment remains the most important influence on the modern character of warfare. Also, the products of the Enlightenment create an imperative for the conduct of modern warfare.

“Héraclite” by Johannes Moreelse (Wikimedia)

Wars go hand in hand with social revolutions.[2] In ancient Greece, the prerequisite for basic democratic rights was the citizens’ obligation to serve and defend their state.[3] Being able to call people to arms also required the ability to produce an adequate amount of weapons. Yet it is difficult to distinguish between origin and outcome. Was the military the trigger for revolutions or war the outcome of the revolution? According to Williamson Murray and MacGregor Knox, military revolutions leading to or based on revolutions in military affairs drove history.[4] The industrial revolution enabled many changes, including the mass production of weapon systems to a defined standard of minimum quality. A secondary effect resulted in wage dumping, urbanization, poverty and social disorder in European capitals. An unsatisfied population with revolutionary tendencies able to afford and access mass-produced weapons provided the prerequisite for the proletariat’s uprising, leading to several European revolutions and contributing to the establishment of the so-called Communist bloc.[5] As such, Heraclitus and his theory of war as an “evolutionary motor” appear ripe for further elaboration on social-military interdependencies.

In reality, philosophical movements have shaped the military far more than tactical changes or weaponry.

It is common to confuse revolutions in military affairs with military revolutions.[6] Whereas the first highlights developments like the invention of gunpowder, the latter describes milestones like the Thirty Years War or the French Revolution. In reality, philosophical movements have shaped the military far more than tactical changes or weaponry. In particular, the most significant changes to the character of warfare within the last 300 years resulted from the Enlightenment, with its ideas about personal responsibility, professionalism, and governmental control over the military. This was the real military revolution, the one that shaped the understanding and conduct of conflicts by designing the international legal framework within which nations wage war today.

Secularism and the Question of Responsibility

Most importantly for students of war, the Enlightenment introduced secularism, which made monarchs and their military leaders responsible for their deeds. What seems to be a basic assumption in the 21st century rests on a social revolution that occurred more than 300 years ago that required new professional, moral, and military obligations for commanders and leaders. The deeds of men and states were no longer entirely justified by the authority of a divine power.[7]

This sense of responsibility—revolutionary as it was—did not originally look as it does today.[8] Secularism was supported and advanced significantly by the pre-existing concepts of Jus in Bello and Jus ad Bellum.[9] As in ancient times, war could then be justified by divine decision, expressed in a mythic way through oracles. Additionally, the treatment of opposing forces was closely linked to their status as believers, barbarians, or non-citizens. Since the Enlightenment, the concepts of Jus in Bello and Jus ad Bellum must be understood in the context of the Treaty of Westphalia, which ended the Thirty Years War. Its main outcomes were confessional parity within Christianity and the acknowledgment of state sovereignty. In essence, nations agreed to no longer wage religious wars.[10] Additionally, by outlining concepts of  sovereignty, adherence to rules for declaring war and for respecting internal affairs were emphasized.

Moreover, Jus in Bello and Jus ad Bellum added a sense of personal moral as well as political responsibility to the application of these rules in the context of secularism. Before this, as long as monarchs were emplaced—on behalf of God—by the Clerus, governmental decisions were perceived as authorized and endorsed by a higher power. Consequently, military action on behalf of the respective monarch was understood as sanctioned by divine authority.[11] Secularism, by contrast, limited arbitrariness by assigning moral responsibility for decisions to the actors themselves. If God did not inspire all men’s actions, then not all deeds could be justified. This understanding was crucial for developing Jus in Bello. Otherwise, Jus in Bello as well as Jus ad Bellum had to be understood within the framework of divine justification, which might not allow defining barriers for military actions.[12] In particular, this refined Jus in Bello led to a reduction of cruelty towards non-combatants, reducing the use of force in international and non-international armed conflict to avoid inappropriate destruction, regulating the treatment of prisoners of war, and limiting the inclusion of civilians in combat.[13] Therefore, secularism set the preconditions for the conduct of a just war by establishing minimum requirements for the treatment of opponents.[14] It made leaders morally responsible for their decisions.[15]

Responsibility and Professionalism

Professionalism made the military a separate system within the state, directly subordinated to the head of state, the monarch.[16] Secularism and centralism contributed to monarchs’ desired absolutism by disempowering vassals and centralizing power.[17] This process required professional military leaders, who were no longer required to have noble lineage, to be loyal to the monarch. If the armed forces were supposed to be loyal solely to the monarch, it required officers to accept an acknowledged career, increasing the social status of those who served.[18] The development from the pylon tactic over the linear tactic to the column tactic further reinforced the need for separation of military leadership from nobility due to the required knowledge and education.[19] Additionally, tactical progress based on precision, increased firing rates, and improved range of weapons created a requirement for educated officers capable of mastering and employing weapons with increasing technical requirements.[20] Mission command, the understanding of the higher echelon’s intent, and execution of missions in correlation with the operation’s purpose became crucial as communication technology could not keep pace with the necessities of marching distances and planned battlefield maneuvers.[21] Military leaders, subordinated to a monarch and responsible for their deeds, needed professional education to meet their commander’s increased expectations. Nobility itself was no longer sufficient. Being emplaced by divine order or by monarchical generosity did not enable a military leader to employ newly-developed weapon systems or provide the competences to master tactical innovation. It needed to be paired with professional education and training.

Military leaders, subordinated to a monarch and responsible for their deeds, needed professional education to meet their commander’s increased expectations.

Professionalism, Values, and the Question of Unconditional Loyalty

This development made the military a governmental central authority’s instrument of power.[22] Absolutism bound the vassals to the central power of the monarch and governmentalized institutions like schools and a centralized administration. This unconditional subordination of the military under a single person, an individual leader who functioned as the head-of-state, started with the Enlightenment and ended with World War II, which refuted traditional German Militarism. A similar process occurred in the Japanese Empire. Subordinating the military under civilian, governmental control seemed to be the right approach—but moral warfare requires more than that.

“Liberty Leading the People” by Eugène Delacroix (Wikimedia)

If a divine power does not justify men’s deeds, war by a head of state might still be misleading. World War II demonstrated, especially on the Axis side, that even a national legal framework itself could be insufficient since law is made by men.[23] Modern, western-oriented, democratic states require armed forces that are both loyal to the respective society’s ideas and moral standards and respect Jus in Bello as part of the general obligation of states to international law.[24]

This requirement is of the utmost importance when considering the armed forces are not simply an instrument of military power projection; they ultimately project not only force but also, just as importantly, a society’s values and culture. Contrary to the era of Carl von Clausewitz, today’s military is not always the state’s primary instrument of power.[25] It is one among others, and usually the asset of last resort. The military has to deliver effects, contributing to the achievement of a strategic role in concert with the other instruments of national power.

Conclusion, Current Status, and a Way Ahead

Although weapons technology and tactics developed immensely over the centuries, a cultural evolution like the Enlightenment functioned more importantly as the impetus for developing human responsibility, creating the need to establish a professional officers corps, and  subordinating military forces under a governmental power. Today, these concepts are pillars of customary international humanitarian law. As such, these key developments from the Enlightenment had the most significant impact on the character of warfare. If a god does not dictate destiny and does not designate a head of state or justify all ways to execute an order, mankind retains the authority to choose a course of action. With this choice comes personal, moral responsibility. As a nation’s most powerful and forceful asset, this responsibility shaped the understanding of how and why states wage war.

The liberty of choice seems to be less appreciated than the weight of responsibility, especially in times of military crisis.  Consequently, mankind  seeks excuses and justifications for their failures, cruelties, and violence. The Deus vult or “it is god’s will” of pre-secular times became the  Imperator vult of absolutist and militaristic times.

Western states and armed forces in the 21st century still operate under secular ideas of responsibility, but our next god may have already appeared. Technology has opened the door for automatic, remote-controlled, and autonomous weapon systems. Reducing the risk to a state’s own forces while increasing operational effectiveness and efficiency remain the primary drivers for this trend.[26] Now states are faced with the question of where to draw a red line for artificial intelligence.

Automation introduces a new dilemma for states, one where doing the objectively right thing might also be morally unacceptable. A mathematically correct solution can lead to an unacceptable mistake, and an algorithm can fail.[27] Can a weapon system—responding automatically to a perceived threat or, even worse, operating autonomously—reliably distinguish between friend or foe, combatant or non-combatant, especially when fighting non-state actors? Can a machine, operating on an algorithm, decide responsibly and adhere to a society's moral standard? Technological developments seem to indicate that Artificialis Intelligentia vult may be the next evolutionary step when it comes to the justification of men’s deeds. The responsibility to employ military force as well as to lead, synchronize, and coordinate military weapon systems can not be shifted to a higher power, entity, or machine. War remains a human decision and therefore the responsibility of those who engage in it no matter how.

Matthias Wasinger is an Austrian Army officer. The views contained in this article are the author’s alone and do not represent the views of the Austrian Armed Forces, the Austrian Ministry of Defense, or the Austrian Government.

This article appeared originally at Strategy Bridge.


[1] Daniel W. Graham, ed., The Texts of Early Greek Philosophy: The Complete Fragments and Selected Testimonies of the Major Presocratics. Translated by Daniel W. Graham (Cambridge: Cambridge University Press, 2010), 450.

[2] Christopher Eagle, ed., Philosophical Approaches to Cormac McCarthy: Beyond Reckoning. Routledge Studies in Contemporary Literature 20 (London: Routledge, 2017), 94-95.

[3] Platon, Politeia: Dialogorum de Republica, Book II-IV.

[4] MacGregor Knox and Williamson Murray, The Dynamics of Military Revolution, 1300-2050 (Cambridge: Cambridge University Press, 2001), 1-14.

[5] Karl Marx, Das Kapital, Critics on Political Economy, passim. Also, it is not uncommon that peacetime revolutions in military affairs like the industrial revolution take decades to show their “revolutionary” character, especially when it comes to their respective military impact. See: Knox and Murray, 12.

[6] Milan Vego, “On Military Theory,” Joint Force Quarterly, no. 62 (2011): 62.

[7] The contrary side of this thought is illustrated nowadays by radical Islamic terror organizations like the Islamic State. It still justifies its terror acts by stating “god's will” behind its undiscriminating cruelty. See Cole Bunzel, “From Paper State to Caliphate: The Ideology of the Islamic State,”, no. 19 (2015): 34; Analysis Paper, https://www.brookings.edu/wp-content/uploads/2016/06/The-ideology-of-the-Islamic-State.pdf (accessed September 29, 2019)

[8] Until the end of World War II, the military leadership felt more responsible towards its respective government. Moltke, the elder, serves as an illustrative example, underlining this fact in his interpretation of On War. See Peter Paret, Gordon A. Craig and Felix Gilbert, Makers of Modern Strategy: From Machiavelli to the Nuclear Age/ Edited by Peter Paret with Gordon A. Craig and Felix Gilbert (Princeton, N.J.: Princeton University Press, 1986), 298. Ethical considerations and international law became more relevant after the “Century of the Great War.”

[9] For the initial steps, see Hugo Grotius and Stephen C. Neff, Hugo Grotius on the Law of War and Peace (Cambridge, New York: Cambridge University Press, 2012), passim.

[10] Malcolm N. Shaw, International Law, 6th edition (Cambridge: Cambridge University Press, 2008), 26.)

[11] A quite illustrative example of this kind of mindset was the crusader’s narrative Deus lo vult! (It is God's will!). Initially the crowd’s response to Pope Urban II., calling for the liberation of Jerusalem 1095, this slogan was in consequence “used” by several monarchs to justify their deeds during these campaigns. See John Agnew, “Deus Vult: The Geopolitics of the Catholic Church,” Geopolitics 15, no. 1 (2010): 40-41. The movement of enormous armies from Europe to the so-called “Holy Land” was an impressive act. See Geoffrey Parker, The Cambridge Illustrated History of Warfare: The Triumph of the West/ Edited by Geoffrey Parker, Rev. and updated ed., Cambridge illustrated histories (Cambridge: Cambridge University Press, 2008), 84. Nevertheless, it appears even more impressive to link a war, consisting of at least seven campaigns, lasting for approximately 300 years, to the will of divine power.

[12] The so-called Islamic State, for example, has no need for a legal reasoning when it comes to its ways and means. The narrative of re-establishing the Caliphate appears to be sufficient. Belligerent acts as well as terror itself and cruelty are justified by referring to a divine power that might intervene in case of need. As long as this higher entity does not intervene, all actions seem to be justified. See Naji, Abu Bakr, The Management of Savagery, The Most Critical Stage through which the Islamic Nation will Pass, 3-5.

[13] Malcolm N. Shaw, International Law, 6th ed. (Cambridge: Cambridge University Press, 2008), 1167-1168.

[14] An illustrative example is the “Common Article in International Humanitarian Law, guaranteeing minimum treatment and protection. See Shaw, 1194.

[15] Matthias Wasinger, “Of the Essence and Worth of the Military,” (Dissertation, University of Vienna, 2017), 105-106.

[16] A phenomenon up to these times was the Chiefs-in-Command “in field”, monarchs, leading their respective armed forces literally at the frontlines like Frederick the Great, or Napoleon. Although beneficial for the morale of the troops, this system had the problem of how to critically reflect the Commander’s plan and execution, if he was the monarch. See Wasinger, 117-118.

[17] See: Samuel P. Huntington, The Soldier and the State: The Theory and Politics of Civil-Military Relations, New edition (Cambridge: Belknap Press of Harvard University Press, 1985), 21-22.

[18] Ibid., 37-39.

[19] In extremis, this led to Kadavergehorsam towards the monarch. Illustrative examples for that are Austrian and German troops, ignoring the orders to withdraw at the end of World War I from the frontiers, imperial Austrian Officers, seeking for the former Emperors permission to join the armed forces of the “First Austrian Republic.” See Johann C. Allmayer-Beck, Peter Broucek and Erwin A. Schmidl, Militär, Geschichte Und Politische Bildung: Aus Anlass Des 85. Geburtstages Des Autors/ Joh. Christoph Allmayer-Beck; Herausgegeben Von Peter Broucek Und Erwin A. Schmidl (Wien: Böhlau, 2003), 412. Or consider the reluctance of German Officers in World War II to support the assassination of Adolf Hitler by stating: “A Prussian Field Marshall does not revolt.” See William-L Shirer, The Rise and Fall of the Third Reich: A History of Nazi Germany, Fiftieth anniversary edition (New York: Simon & Schuster, 2011), 981.

[20] Knox and Murray, The Dynamics of Military Revolution, 1300-2050, 102-110.

[21] Carl v. Clausewitz, Michael Howard and Peter Paret, On Victory and Defeat: A Princeton Shorts Selection from On War (Princeton, N.J.: Princeton University Press, 2011), 188.

[22] It is an interesting detail that up to this moment, the Pope needed neither an Army nor protection. Being God’s representative on Earth, the position of the Head of the Catholic Empire was––if at all––endangered by internal conspiracy, but not external threats. The need for the Swiss Guards and Castel Sant’Angelo was urged by secularism. See Wasinger, Of the Essence and Worth of the Military, 96.

[23] After World War II, rarely a judge or lawyer within the so-called Axis Powers was sentenced. Even worse, all operations, ethnic cleansings, humiliations, mass murder, deportations etc. have been in line with national law. See Ingo Müller and Ingo Vagts, Hitler's Justice: The Courts of the Third Reich (Cambridge, Mass.: Harvard Univ. Press, 1994), 97. A national legal framework, therefore, might not be enough.

[24] This seems to be not only applicable to the western hemisphere. Similar movements and tendencies occurred in Asia at the same time. See Cecil B. Currey, Victory at Any Cost: The Genius of Viet Nam's Gen. Vo Nguyen Giap, First the warriors ed. (Dulles, Va.: Potomac Books, 2005), 104-105. Complementary, the legitimate government is supposed to respect the obligations for Jus ad Bellum.

[25] Clausewitz, Howard and Paret, On Victory and Defeat, 177. One can assume that Clausewitz’s understanding of strategy was in theory far above his definition of what might be nowadays military strategy. He has to be understood in light of the times he lived in, an era, in which the military was the only instrument of national power, directly and unconditionally subordinated to the monarch. Therefore, any definition of strategy out of this period is heavily affected by today’s military strategy. See Wasinger, Of the Essence and Worth of the Military, 63.

[26] Greg Allen and Taniel Chan, Artificial Intelligence and National Security. A study on behalf of Dr. Jason Matheny, Director of the U.S. Intelligence Advanced Research Projects Activity (Harvard Kennedy School, 2017), 13.

[27] Ibid., 67-70.

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