Is it possible to persuade mankind to live without war? War is an ancient custom which has existed for at least six thousand years. It was always evil and usually foolish, but in the past the human race managed to live with it. Modern skill has changed this. Either man will stop war, or war will stop man. For the present, it is nuclear weapons that cause the greatest danger, but bacteriological(  ) or chemical weapons may, before long, offer an even greater threat. If we succeeded in stopping war, there would be no danger for us. To do this, we need to persuade mankind to look upon international questions in a new way, not by contests of force, in which the victory goes to the side which is most skillful in massacre ( ),but by judging in accordance with agreed rules of law. It is not easy to change old mental habits, but this is what must be attempted. There are those who say that the adoption of this or that ideology  would prevent war. I believe this to be a complete error. All ideologies are based upon beliefs without proof which are, at best, doubtful, and at worst, totally false. Those people who believe them are willing to go to war in support of them. The movement of world opinion during the past two years has changed very largely such as we can welcome. It has become a common belief that nuclear war must be avoided. Of course, very difficult problems remain in the international world, but the spirit in which they are being approached is a better one than it was some years ago. It has begun to be thought, even by the powerful men who decide whether we shall live or die, that agreements should be reached even if both sides do not find these agreements wholly satisfactory. It has begun to be understood that the important conflict nowadays is not between East and West, but between Man and the bomb. Which of the following words can best describe the author's feeling in writing this passage?
Disappointed. Doubtful. Worried. Hopeful.