Quite an oxymoron, isn’t it? If a woman is barren, how come she has a son? And if she has a son then she cannot be barren!
The great Indian philosopher Šankara (7th century A.D.) well renowned for his Advaita philosophy gives this simile to ridicule his Buddhist opponents.
There was a sect of Buddhist philosophers called Vijñänavädis who claimed that the world around us does not actually exist. It exists only in our minds and not in reality.
Probably Šankara forgot that his own grand teacher Gaudapäda supported almost the view of Vijñänavädis. Through a long list of arguments (refer to my book “Important missing dimensions in our current understanding of the mind”), Gaudapäda ‘almost’ proved the nonexistence of the world.
Even though Šankara explained it as above, many of his followers (Advaitis) even today stick to the line of Gaudapäda and say that world does not exist. That made Šankara the target of criticism from his opponents in his own Vedic fold, who branded his as a ‘Buddhist in disguise’!