The validity of a comprehensive hypothesis such as the "new global tectonics" may be tested on the basis of either pragmatic usefulness or scientific acceptability. Unquestionably, this hypothesis has been extremely successful pragmatically in relating diverse geological and geographical observations and conjectures, thus sparking a revolution in the earth sciences, the effects of which will determine the dominant directions of research for years to come.

Tests of the scientific validity of such a wide-ranging hypothesis are difficult to design and apply. The most convincing tests will involve prediction of behavior unrelated to the phenomena which the hypothesis was devised to explain. It is not surprising that the hypothesis is especially successful for the oceans. However, its application to orogenic belts, to deformation within continents, and to paleogeologic and paleoclimatic reconstructions is less obvious and has yet to be evaluated. These are difficult exercises. The demonstration that diverse geologic facts and inferences can be rationalized is permissive, but not compelling, evidence of scientific validity; essentially the same data have served to validate other quite different hypotheses.

This paper points out some of the apparent weaknesses of the new-global-tectonics hypothesis and suggests some possible tests of the major tenets of the hypothesis.