All I need to do is to point to a single example of a perfect program. I am sure there are a lot of perfect programs around us - built into phones, smartcard readers, TV sets. Nostrademus also pointed out a couple areas where bug-free is the norm. If we can go for simple ones, I have written a couple of them in my career - simple programs that do one thing and do it perfectly. I wouldn't be a professional engineer if I didn't pass those exams.<p>What you have to do, on the other hand, to back up your bold statement that developing perfect software is impossible, is to prove it impossible.<p>Good luck.