[amtamt]

Even two wrong, but countering, inputs can sometimes provide right answer, so the rational above has some merit.

But if I interpret the question with line of thinking "should I anticipate right/ full answers despite incorrect/ incomplete inputs?" I think Baggage was pointing out the problem in the logic why such questions should arise.

I would expect the question to be phrased "under what circumstances the machine with provide wrong outputs?", and would have hoped for Babbage (or may be anyone) explaining many ways how things could go wrong.