I might argue that it may fix problems that aren't fixable otherwise.
My experience in this area is very old, but I found that the biggest benefit
of formal methods was not so much the proof but the flaws discovered and
fixed on the way to the proof.
In conclusion, it seems an awful effort to
The obvious difference is parts. In manufacturing, things are assembled
from well-known, well-specified, tested parts. Hmmm
... If you look at other things
that people build, like oil refineries, or commercial aircraft, we can
deal with complexity much more effectively than we can with
