It is certainly desirable, or perhaps even necessary, to review from time to time the state of the exact or applied sciences. This attitude definitely holds in the case of cosmology. Granted, cosmology and cosmogony—this separation of terms has become obsolete today—are, no doubt, two of the oldest examples of man's innate curiosity. Although thousands of years ago they already contained traces of scientific elements and sometimes even noteworthy attempts at more or less plausible theories—nevertheless, cosmology and cosmogony have retained, in the main, their speculative character.⁽¹⁾