... and most of the examples shows proving a positive as well, and also clearly exerts why the statement I said in my post is not falsifiable. Your original statement, was, btw, "it is almost impossible to prove a positive." So, how is it nearly impossible to prove "this swan is white," but highly possible to prove "no swan has ever been black?"

I can prove there is a mouse that is blue and black on my desk, but I cannot prove that there has never been a red and black mouse on my desk, I can only assert such.