French Jesuit theologian Denis Petau (1583-1652), referring to the time gap implied between Gen. 1:1 and 1:2, wrote, "The question of how great an interval there was, it is not possible, except by inspiration, to obtain knowledge of it." Catholic philosopher Benedict Pereira (1535-1610) wrote, "even though before the last day, the heavens and the elements were made subsequent to the substance, nevertheless, they were not perfected, completely furnished until the period of six days. However long that darkest day of the world lasted, whether it lasted one day or more than one day or less than one day is not clear to me or any other mortal, unless one is divinely made so."