The worry about our own actions will continue. It may grow as our power over nature increases. Against this worry there exist two weapons: understanding and courage. Of the two, courage is more important but understanding must come first.
We are frequently alarmed by imaginary dangers, while disregarding risks which are much more real. There should exist a close interaction between public opinion on the one hand and technical progress on the other. For this end an understanding of modern scientific developments is required. There is an increasingly urgent need to know. Little is done to satisfy this need. The opinion has gained ground that this need can in fact not be satisfied.
At the same time, more and more people believe that the scientists and technical people themselves are responsible for the changes which their ideas and inventions have brought about. The scientist is put in the position where his voice is heard, not only in the highly specialized fields in which he is an expert, but also in the much more general matters which are affected by his discoveries. The real source of important decisions in our country is the people. We believe that this is rightly so, and we believe that it is not proper if scientists take over any essential part of these decisions.
The responsibility of a technical man certainly includes two important functions. One is to explore nature and to find out the possible limits of our power over nature. The other is to explain what he has found in clear, simple, and straightforward terms, so that essential decisions can be made by all the people of our country—to whom the power of decision properly belongs, and whom the consequences of these decisions will ultimately affect.
To explain scientific and technical matters is not easy, and to become familiar with all science might actually be impossible. In the specialized field of physics there have been revolutionary developments in the twentieth century like the theory of relativity discovered by Einstein and the theory of the atom originated by Niels Bohr. These new discoveries are not easy to understand, and every good physicist has spent years of his life trying to get thoroughly acquainted with their meaning. All of us who have done so feel that we are well rewarded by the better understanding of nature which we have acquired. But it is not necessary to talk of these matters here.
What we have to discuss in this book is connected with parts of atomic and nuclear physics which are much more elementary. The facts which we shall present in a simple fashion are sufficient to give the reader an orientation in the seemingly bewildering fields of nuclear energy and atomic explosions.
We shall have to start by describing atoms and nuclei. These are rather small objects, but this circumstance need not particularly bother us; and it is not necessary to frighten ourselves with the idea that we are talking about “unimaginably” small objects. Our minds adapt themselves quite readily to new dimensions; and while we are talking about nuclei, we can temporarily forget that any bigger objects exist. Real difficulties arise only when science discovers laws which seem to contradict common sense. This does not happen frequently, and we shall not need to dwell upon such subjects.
The difficulties of explaining science are increased by the fact that scientists have developed a language of their own which they practice and perfect by talking to each other. One sometimes has the impression that they talk to each other exclusively. The authors feel that their own “native tongue” is this scientific language; this book is an effort at a translation.
A further difficulty is connected with the special subject: radioactivity. The great practical importance of this subject has dawned upon the public in connection with the explosion at Hiroshima. This was a frightening occasion, and the subsequent developments and prospects are no less frightening. It is not necessary that everything connected with nuclear explosions should be equally frightening; and it is important that we should approach the subject with an open mind and with as few emotions as is humanly possible. The emotions have their necessary place when we get to the stage in which we want to decide our actions. We suggest to the reader that he should delay this stage until the time when he has finished reading the book.
The greatest difficulty in discussing the radiation hazards arises because the working of living organisms is involved. Basically, we are in the dark about the question how such an organism works. We are equally in the dark about the question how such an organism is affected by radiation. It would therefore seem that we must remain in doubt whether or not radioactivity is dangerous, except for those cases where obvious damage has been done. Since the immediate effects of radioactivity are not perceived by our senses, we are faced with the thought of an invisible menace of unknown extent. Some of the harmful consequences may show up years later, and therefore even the absence of any observed damage will not reassure people.