El mundo, para Baruch Spinoza, un filosofo moderno, ha existido ab aeterno. Por el contrario, para Maimonides y Tomas de Aquino, teologos medievales, no necesariamente: admiten la posibilidad de que comenzo a existir. La cosmologia actual y predominante sostiene la teoria del bing-bang. El articulo, con enfasis en los autores mencionados, discurre sobre algunos conceptos filosoficos que en algo atanen a la cosmologia. Sugiere que la creacion del mundo por Dios, conforme al Genesis biblico, no parece incompatible con el bing-bang. The world, for Baruch Spinoza, a modern philosopher, has existed ab aeterno. By contrast, for Maimonides and Thomas Aquinas, medieval theologians, not necessarily: they admit the possibility that it came into existence. Current cosmology holds the bing-bang theory. This article, with emphasis on the authors mentioned, runs on some philosophical concepts somewhat relevant to cosmology. It suggest that the creation of the world by God, according to the bibilicar Genesis, seems to be compatible with the big-bang theory.