I am certainly not adequately trained to describe or enlarge on human fears, but there are certain features of the fears dispelled by scientific explanations that stand out quite clearly. They are in general those fears that once seemed to have been amenable to prayer or ritual. They include both individual fears and collective ones. They arise in situations in which one believes that what happens depends not only on the external world, but also on the precise pattern of behavior of the individual or group. Often it is recognized that all the details of the pattern may not be essential to the outcome but, because the pattern was empirically determined and not developed through theoretical understanding, one is never quite certain which behavior elements are effective, and the whole pattern becomes ritualized. Yet often fear persists because, even with the most rigid ritual, one is never quite free from the uneasy feeling that one might make some mistake or that in every previous execution one had been unaware of the really decisive act. To say that science had reduced many such fears merely reiterates the obvious and frequent statement that science eliminated much of magic and superstition. But a somewhat more detailed analysis of this process may be illuminating.

The frequently postulated antique worry that the daylight hours might dwindle to complete darkness apparently gave rise to a ritual and celebration which we still recognize. It is curious that even centuries of repetition of the yearly cycle did not induce a sufficient degree of confidence to allow people to abandon the ceremonies of the winter solstice. This and other fears of the solar system have disappeared gradually, first, with the Ptolemaic system and its built-in concept of periodicity and then, more firmly, with the Newtonian innovation of an universal force that could account quantitatively for both terrestrial and celestial motions. This understanding provides a very simple example of the fact that one can eliminate fear without instituting any controls. In fact, although we have dispelled the fear, we have not necessarily assured ourselves that there are no dangers. There is still the remote possibility of planetoid collision. A meteor could fall on San Francisco. Solar activities could presumably bring long periods of flood or drought. Our understanding of the solar system has taught us to replace our former elaborate rituals with the appropriate action which, in this case, amounts to doing nothing. Yet we no longer feel uneasy. This almost trivial example is nevertheless suggestive, for there are some elements in common between the antique fear that the days would get shorter and shorter and our present fear of war. We, in our country, think of war as an external threat which, if it occurs, will not be primarily of our own doing. And yet we obviously also believe that the avoidance of the disaster depends in some obscure or at least uncertain way on the details of how we behave. What elements of our behavior are decisive? Our weapons production, our world prestige, our ideas of democracy, our actions of trust or stubbornness or secrecy or espionage? We have staved off a war and, since our behavior has involved all these elements, we can only keep adding to our ritual without daring to abandon any part of it, since we have not the slightest notion which parts are effective.