When facts change your mind, that's not always science. It may be history. I changed my mind about an important historical question: did the nuclear bombings of Hiroshima and Nagasaki bring World War Two to an end? Until this year I used to say, perhaps. Now, because of new facts, I say no. This question is important, because the myth of the nuclear bombs bringing the war to an end is widely believed. To demolish this myth may be a useful first step toward ridding the world of nuclear weapons.
Until the last few years, the best summary of evidence concerning this question was a book, "Japan's Decision to Surrender", by Robert Butow, published in 1954. Butow interviewed the surviving Japanese leaders who had been directly involved in the decision. He asked them whether Japan would have surrendered if the nuclear bombs had not been dropped. His conclusion, "The Japanese leaders themselves do not know the answer to that question, and if they cannot answer it, neither can I". Until recently, I believed what the Japanese leaders said to Butow, and I concluded that the answer to the question was unknowable.
Facts causing me to change my mind were brought to my attention by Ward Wilson. Wilson summarized the facts in an article, "The Winning Weapon? Rethinking Nuclear Weapons in the Light of Hiroshima", in the Spring 2007 issue of the magazine, "International Security". He gives references to primary source documents and to analyses published by other historians, in particular by Robert Pape and Tsuyoshi Hasegawa. The facts are as follows:
1. Members of the Supreme Council, which customarily met with the Emperor to take important decisions, learned of the nuclear bombing of Hiroshima on the morning of August 6, 1945. Although Foreign Minister Togo asked for a meeting, no meeting was held for three days.
2. A surviving diary records a conversation of Navy Minister Yonai, who was a member of the Supreme Council, with his deputy on August 8. The Hiroshima bombing is mentioned only incidentally. More attention is given to the fact that the rice ration in Tokyo is to be reduced by ten percent.
3. On the morning of August 9, Soviet troops invaded Manchuria. Six hours after hearing this news, the Supreme Council was in session. News of the Nagasaki bombing, which happened the same morning, only reached the Council after the session started.
4. The August 9 session of the Supreme Council resulted in the decision to surrender.
5. The Emperor, in his rescript to the military forces ordering their surrender, does not mention the nuclear bombs but emphasizes the historical analogy between the situation in 1945 and the situation at the end of the Sino-Japanese war in 1895. In 1895 Japan had defeated China, but accepted a humiliating peace when European powers led by Russia moved into Manchuria and the Russians occupied Port Arthur. By making peace, the emperor Meiji had kept the Russians out of Japan. Emperor Hirohito had this analogy in his mind when he ordered the surrender.
6. The Japanese leaders had two good reasons for lying when they spoke to Robert Butow. The first reason was explained afterwards by Lord Privy Seal Kido, another member of the Supreme Council: "If military leaders could convince themselves that they were defeated by the power of science but not by lack of spiritual power or strategic errors, they could save face to some extent". The second reason was that they were telling the Americans what the Americans wanted to hear, and the Americans did not want to hear that the Soviet invasion of Manchuria brought the war to an end.
In addition to the myth of two nuclear bombs bringing the war to an end, there are other myths that need to be demolished. There is the myth that, if Hitler had acquired nuclear weapons before we did, he could have used them to conquer the world. There is the myth that the invention of the hydrogen bomb changed the nature of nuclear warfare. There is the myth that international agreements to abolish weapons without perfect verification are worthless. All these myths are false. After they are demolished, dramatic moves toward a world without nuclear weapons may become possible.