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Guest Post: The moral lessons of Hiroshima and Nagasaki

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Written by William Isdale

University of Queensland

This year is the 70th anniversary of the atomic bombing of Hiroshima and Nagasaki. Are there any moral lessons we can learn from that historical episode? I think so.

Recently I delivered a talk on radio about this topic. I argue that one key reason to study history is to learn lessons about human nature. The war in the Pacific against Japan can tech us about, (1) our tribal natures, (2) the limits of empathy when we kill from a distance, and (3) the ratchet-up effect of retaliatory violence.

We have a moral obligation to take heed of those lessons, for instance by reining in our more dangerous traits. The existence of nuclear weapons, because of their destructive power, makes the imperative to understand and control our natures all the more significant.

Below is a slightly adapted version of what I said.



This year marks 70 years since the end of World War Two. A conflict that ended with the use of the most destructive weapons ever invented – the atomic bombs, dropped on Hiroshima and Nagasaki.

Has it ever occurred to you to ask, just what is the point of commemorating wars? Do we commemorate them because they are interesting, or are there more important reasons?

If you’ve ever attended a war commemoration ceremony, you’ve probably heard speakers talking about the gratitude that we owe to those who fought to defend our way of life. Or speeches that urge us to reflect on the tragedy of lives lost, and the risks of rushing into conflict. And those are good reasons for remembering wars. But, in my view, they’re not the most important ones.

The Scottish philosopher David Hume once wrote that the principal reason to study history is to discover  “the constant and universal principles of human nature”. And in no other area of human life is learning those lessons more important, than when they concern war.

By studying wars we can learn lessons about ourselves. About how we get into them – why we keep fighting them – and what we do to justify extraordinary levels of cruelty and destruction visited on others.

Today I want to uncover three lessons about human nature that are revealed to us by the war in the Pacific against Japan – and particularly, from the nuclear bombing of Hiroshima and Nagasaki.

The first lesson is that human beings are tribal creatures.

The primatologist Frans de Waal tells a story he once heard from an ethologist, who was studying a tribe in the highlands of New Guinea. One day, the researchers offered an aeroplane flight to two of the tribesmen. They agreed. But before boarding they made an unusual request: could they please bring two large stones onboard? The researchers asked why. The tribesmen explained that they wished to drop them on an enemy village. The ethologist later remarked, “we have been present for the invention of bombing by Neolithic man.”

When American airmen flew those fateful missions over Hiroshima and Nagasaki, the technology was, of course, very different. But human psychology hasn’t changed all that much. The same sorts of feelings that motivated our ancestors to inflict violence, can motivate us too. Einstein said that, “Nuclear weapons have changed everything, except our modes of thought.”

The tribal dimension of the war with Japan can be seen in the way that many people failed to draw a distinction between military leaders and civilians. There was a demonisation of whole races and nations. On the Japanese side, some people believed in their racial superiority as descendants of the Sun God. Such a view made it easier to justify cruelty against Allied prisoners of war. And on the Allied side, some spoke of the Japanese as if they were sub-human. The Australian General, Sir Thomas Blamey, for example, said that the Japanese were a  “cross between a human being and the ape.”

What does this have to do with Hiroshima and Nagasaki? Well, at the very least, a tribal hatred of an enemy makes it easier to put aside questions of necessity and proportionality in deciding whether to attack them.

By early 1945, it was obvious that Japan would be defeated. The nation lay in ruins. The economy had been brought to its knees by a naval blockade, and the Soviet army was poised to invade. Today, many historians believe that Japan would have surrendered around the same time anyhow, without the nuclear bombing.

In deciding whether to use the nuclear bombs, Churchill later wrote that there was  “unanimous, automatic, unquestioned agreement.” The historian Paul Ham says that not one member of the Target Committee raised the moral case against using them. No real consideration was given to alternatives. The Secretary of War, Henry Stimson, raised the possibility of providing a demonstration – but this was quickly dismissed.

If studying war reveals a tribal dimension to our thinking, then we have an obligation to keep that tendency in mind, so we can rein it in, and avoid needlessly sacrificing lives.

A second lesson that wars can teach us, is that it’s easy to kill from a distance.

George Orwell once wrote about his experience fighting in the Spanish Civil War. He told a story about how we once refrained from shooting a man. Orwell saw the man running half-dressed, holding up his trousers with both hands. Orwell said, “I had come here to shoot at Fascists. But a man who is holding up his trousers isn’t a Fascist, he is visibly a fellow creature, similar to yourself, and you don’t feel like shooting at him.” For Orwell, that small detail had humanised his enemy.

But at 20,000 feet, the chance that you’ll humanise your enemy is much more remote. There is no moral difference between bombing people, and shooting them, one by one, with a pistol. But it feels very different. You cannot see them. You did not intend that particular woman, or that particular child, to die.

The psychological point is that tales of depravity against identifiable individuals are more shocking to us than the deaths that modern warfare tends to result in – of large numbers of individuals who we don’t see and can’t identify with. And that should worry us, because what shocks us most is not a good proxy for what is most morally egregious.

The value of history is in humanising those statistics – through telling their stories, showing their suffering, and also, by reminding us of our tendency to forget them in the aggregate.

Let me provide you with one final lesson that I think war can teach us about ourselves. Namely, that it tends to bring out a retributive side to our psychology.

On the 1st of September 1939, two days before Britain declared war on Germany, President Roosevelt gave a speech on radio. Roosevelt expressed his fear that hundreds of thousands of people, who would have no role to play in the upcoming conflict, would be victims of it. Roosevelt called on the European nations to affirm that their armed forces, “shall in no event, and under no circumstances, undertake the bombardment from the air of civilian populations.”

This lofty principle would not be respected, including by the United States, who by July 1945 had firebombed 66 Japanese cities. The philosopher A.C. Grayling, in his book Among the Dead Cities, explains how the Allies slid away from this principle of not bombing civilians. Partly, it because of problems of navigation and bomb-aiming. Hitting precise targets was difficult, especially in the earlier years of the war in Europe, when the technologies were less advanced, and where the skies were often cloudy. But another key cause of the slide was due to the ratchet-up effect of retaliatory violence.

Consider this example from Europe. On the night of the 24th of August 1940, a group of German bombers accidentally dropped their bombs on London. They had intended to hit an aircraft factory, but they were off course. In London, though, no one knew the bombing was a mistake. The delicate moral norm against killing civilians was undermined. The British War Cabinet ordered retaliation – sending eighty-one bombers to Berlin the next night.

The tit-for-tat drove both sides further and further into moral depravity. Popular opinion sometimes demanded it. On one occasion, Churchill was greeted with whoops of approval, when he said to a gathered crowd, “we will mete out to the Germans the measure, and more than the measure, that they have meted out to us.”

Hitler, in his own rousing speech in Berlin, said “If the British air force drops two thousand or three thousand kilograms of bombs, then we shall drop a hundred and fifty thousand, two hundred and thirty thousand … one million kilograms. … When they say they will attack our cities, then we will wipe out theirs.”

World War Two was undoubtedly just in its aim to defeat German and Japanese militarism. But the fact that an overall cause may be right does not justify everything done in pursuit of it. Retribution can threaten the overall justice of a war, because it obscures the moral requirement to avoid killing civilians except where absolutely necessary. And, it leads us away from the principles that reflect our better angels, and into the eye-for-an-eye mentality that leaves us all blind.

So far, I’ve given you three examples of lessons we can learn about human nature from studying wars. Let me end with one example of how failing to heed the lessons of history can be fraught with danger. This final lesson is about nuclear weapons – and what better time to reflect on them than now, 70 years after their first, and only, use in war.

As you may know, Alfred Nobel came to prominence after inventing dynamite. And then, he founded the Nobel Peace prize. You might think that Nobel’s two legacies seem pretty incompatible. But Nobel didn’t think so. In the 1860s, Nobel said that his invention of dynamite would “sooner lead to peace than a thousand world conventions, [since] as soon as men will find that in one instant whole armies can be utterly destroyed, they will surely abide in golden peace.”

Unfortunately the golden peace didn’t come. The Harvard psychologist Steven Pinker has pointed out that similar claims were made on behalf of submarines, artillery, and the machine gun, amongst others. Some, like the political scientist Kenneth Waltz, have argued that nuclear weapons also make the world safer, since potential aggressors will be terrified by nuclear annihilation.

On the 6th of August 1945, the American physicist Luis Alvarez rode in the backup plane that accompanied the nuclear bombing mission on Hiroshima. Alavarez saw the bright flash of the Hiroshima explosion, and felt the two sharp slaps of the bombs’ shock waves hitting the plane. On the trip back to the island base at Tinian, Alvarez wrote a letter to his four year old son, Walter, about his experience. He said, “What regrets I have about being a party to killing and maiming thousands of Japanese civilians this morning are tempered with the hope that this terrible weapon we have created may bring the countries of the world together and prevent further wars.” Alvarez wrote about Nobel’s prediction that dynamite would stop wars, which hadn’t come true. Then he said, “Our new destructive is so many thousands of times worse that it may realize Nobel’s dream.”

Here, I think, is a perfect example of failing to learn the lessons of history. After both the invention and dynamite and atomic weapons, the technologies had changed and destructive power had greatly increased. But what Nobel, and Alvarez failed to notice was that human nature had not. The people who would decide to employ such weapons would still be as tribal, vengeful, or prone to all kinds of errors or miscommunications, as anyone before them. And in a nuclear-armed world, a mishap could mean catastrophe.

In the 1960s, new atomic weapons – hydrogen bombs – were developed that had over a thousand times the destructive power of the bomb dropped on Hiroshima. The Titan II missile had a warhead with a destructive power of over three times that of all of the bombs dropped in World War Two combined, including the two atomic bombs dropped on Japan.

If you’re not worried about our fallible natures leading to nuclear disaster, then ponder two scenarios. Imagine a vengeful Hitler with access to nuclear weapons in his bunker in 1945, as the Red Army closes in and he makes plans to kill himself. Or consider Richard Nixon, at the height of the Watergate Scandal – emotionally unstable, drinking heavily, and talking to portraits on the walls in the White House. A man who had authority to order nuclear strikes.

Perhaps the overarching lesson that the histories of war teach us, is that human beings are not always rational. And in a nuclear-armed world, that should scare the hell out of you.


For anyone interested in learning more, I highly recommend:

Hiroshima Nagasaki – Paul Ham

Humanity: A Moral History of the Twentieth Century – Jonathan Glover

Among the Dead CitiesA.C. Grayling

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1 Comment on this post

  1. Hi
    Thanks for a very thought-provoking discussion. I’ve been trying to track down that stone dropping story for years. Do you have the ethologists name? I was told Malinowski but a diligent search through his works didnt turn anything up

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