The way I understand it (and I am probably completely wrong, seeing as I am not a physicist, nor a mathematician), string theory is to scientific theories as a

The way I understand it (and I am probably completely wrong, seeing as I am not a physicist, nor a mathematician), string theory is to scientific theories as a class is to objects in OOP. You can indeed never falsify string theory itself, but you absolutely can falsify a theory derived from string theory by picking parameters for it.