In planning the trip to the moon, we knew the three most important elements: where we were, where we wanted to go, and how to get there–rockets. In addition, modification of the environment raises many legal, sociological, and psychological problems that are not encountered in going to the moon. It is accurate to visualize law and science as rotating about a common axis of “uncertainty.” Members of both professions are concerned with estimating the probabilities of experiencing primary, secondary, and tertiary effects and then with establishing some degree of certainty about the magnitude of those effects. The issues common to law and science are becoming more evident. If it is true that the first organized thought was the precursor of science and that the first difference in opinion was the precursor of law, then unquestionably it is true that weather modification typifies a longstanding combination of legal and scientific uncertainties.