Programming systems can be treated scientifically, but they can also be treated deductively (like math). It's possible to have full knowledge of what's going on if you treat it like a deductive system. If your primary way of learning is through experiment, then yes, you will be wrong a lot of the time. But then I would never claim you had a good reason for believing anything.

I can't view the stackoverflow link right now, but the top answer basically claimed "I feel strongly about my reasoning, but nevertheless, I could be wrong". How could that be unless you made a mistake? The system is logical!