In programming, you have true and false, and generally things fall into one or the other category with no human input.
In law, you have concepts like "reasonable", and a whole lot of human input, by design.
So my expectation would be that if software vendors were to be held responsible for bugs in their products, the standard they would be expected to adhere to would be "reasonable expectation of proper functioning", with humans intepreting what "reasonable" means.