FOM: Do realists really know?

[Peter Schuster]

Would anybody be so kind to explain why and how   
the law of bivalence, i.e., that any statement is 
either true or else false, does follow from what 
traditionally is called the realist philosophy 
of mathematics, i.e., that mathematical objects 
are existent disregarding whether they are known? 

A similar question has recently been put by Fred Richman; 
to my knowledge it has not been answered yet. 

Peter Schuster.