Philosopher Anthony Clifford Grayling was destined to write this book. He grew up in the (then) British colonies of Northern Rhodesia and Malawi, studied at Magdalen College, Oxford, and taught at Birkbeck, University of London, before founding the New College of the Humanities in London. He has written some thirty books, including the well received Among the Dead Cities,[1] and is a media personality and public policy activist. In War: An Enquiry, he has broadened his perspective to include the ethics of war as a whole.

Grayling believes that, though it will be difficult, humankind can transcend war as a problem-solving mechanism. War-making, he argues, is not inherent in human nature, but a product of social institutions that lead war's participants in directions they would not follow on their own. If so, then the propensity for war may be blunted and even, in time, eliminated by redirecting those institutions.

Grayling argues his case in three parts on three levels of abstraction: "War in History and Theory," "The Causes and Effects of War," and "Ethics, Law and War." Part I (chaps. 1–3) concentrates on historical facts;[2] II (chaps. 4–5) offers a socio-analytic discussion of people's grounds for war-making; and III (chaps. 6–7) assesses the likelihood of achieving lasting peace at a time when war is being automated and traditional just war theory is withering away.

Chapter 1 concerns ancient wars, the second chapter medieval, renaissance, and modern wars. Grayling provides particulars of significant wars and notable battles, being careful to inform the reader precisely when and where revolutionary new weapons were introduced. He also calls attention to the honoring of "primitive" rituals and accommodations vs. the adoption of "no holds barred" tactics.

In chapter 2, the author emphasizes the efficacy of new weapons, tactics, force organizations, types of civilian personnel, and motivational objectives. Examples include hand-to-hand combatants like those of the Vikings (49–50), Frankish infantry at Poitiers (51–53) and Egyptians at Ain Jalut (65). He discusses the failed strategic motivations for the Crusades and consequent outcomes (53–58). He points out that not horsemanship alone, but the nationalization of tribes, the mobilization of a population of some one million, and, in particular, the extermination of defeated peoples accounted for the successes of Mongol armies over several generations (58–67). By contrast, in the fifteenth century, maintenance of supply lines and advances in weaponry had become most vital to military success (69–70).

Except in the unique real-world case of Japan (and Machiavellian military theory), close-quarter combat fell into disfavor as "artillery and guns reintroduced distance" as the decisive element in combat (71). Naval power, of course, also became a game-changer, as did a shift from seasonal mercenaries to standing professional armies (76). Multinational mercenaries remained commonplace, but, the author observes, "in the wars of the American and French revolutions, sentiment and belief in the rightness of the cause being fought for gave far more of an edge to military effectiveness than any admixture of irregulars could achieve" (77–78).

Chapter 3, the best of the seven, examines theories of war from the Renaissance to modern times. Grayling shows that Enlightenment figures such as Frederick the Great and Dietrich von Bulow required that war theory be science-based. Subsequent military theorists, most notably Carl von Clausewitz, stressed the role of sentiment and emotion (87–92). Focusing on psychological factors, Clausewitz highlighted the value of talent, creativity, and audacity, whether in reaching limited objectives or annihilating the enemy. Some have argued that these views remained influential during the First World War and, greatly magnified, during the Second, with the intensive recourse to aerial bombardment, tanks, and other armored vehicles. Since then, of course, the development of nuclear arsenals and concepts of asymmetrical warfare have greatly complicated military theorizing.

In Part II, Grayling contends (chap. 4) that humankind can live without having wars, and (in chap. 5) that the horrific consequences of war make that objective desirable. He investigates whether wars inevitably derive, as it were genetically, from human nature or from correctable social arrangements. He admits that the long-prevailing former view (126) is buttressed by ethological data, showing, for instance, that some animals kill members of their own species. Social Darwinists inspired by Francis Galton have endorsed this line of argument, as did Nazi eugenicists and, more recently, theorists like E.O. Wilson and Richard Dawkins.

Grayling maintains that such cultural phenomena as altruism can override genetic predispositions. He is especially taken with political scientist Kenneth Waltz's "levels of analysis framework,"[3] which posits that causes of war exist on the level of the individual (e.g., Genghis Khan, Adolf Hitler), the state (e.g., the "Triple Entente"), and the international order (e.g., the "proxy wars" of the Cold War era) (141–58).

The author stresses the dire existential need for pacifism (chap. 5): some 500 million people have died in wars, 20 percent of them in the twentieth century. Surviving combatants suffer from Post Traumatic Stress Disorder (PTSD, formerly "shell shock" or "combat fatigue") and traumatic brain injury (TBI). One favored treatment involves "forward psychiatry" based on PIE (Proximity to war zone, Immediacy, and Expectation of recovery). This is not to mention the massive displacement of civilians and the traumas they sustained. The enduring question is whether such indisputable evils are outweighed by perceived positive consequences of war.

Chapter 6 concerns normative constraints on war, specifically, just war theory and international humanitarian law. The author finds the former inadequate, the latter compelling but ill-enforced. Churchmen developed just war theory, he maintains, to square pacifist Christian teachings with the motives of rulers for going to war. Also addressed in this chapter are the debates about whether an individual may refuse to participate in war, whether restraint is morally mandatory, whether the present-day prospect of mass annihilation nullifies just war theory, and whether the theory pertains to "asymmetrical, insurgent, and terrorist conflict" (204). Grayling argues that humanitarian international law better defines jus in bello limitations on weapons and methods used in warfare and the need to protect noncombatants, with special attention to the suffering of women (208–13).

The author's final critique of war (chap. 7) concerns the extent to which the task of killing is increasingly being transferred from human to machine control, notably via lethal autonomous weapons (LAWs) (222 ff.). Killer drones are a step in this direction, and other modes of robotic mayhem will no doubt soon be devised and deployed.

The casual reader of War: An Enquiry may wonder how the concentration on facts in part I relates to the later treatment of aspirational ideals. The answer lies in Grayling's intermediate step of showing that culture rather than nature generates wars:

Whether or not this reasoning will persuade all his readers, Anthony Grayling's discerning "enquiry" into war will instruct students of military history and theory or members of a collegiate Peace Studies program.