alt Hacker News A programmer has to be able to demonstrate that his program has the required properties. If this comes as an afterthought, it is all but certain that he won't be able to meet this obligation: only if he allows this obligation to influence his design, there is hope he can meet it. Pure a posteriori verification denies you that wholesome influence and is therefore putting the cart before the horse, but that is exactly what happens in the software houses where "programming" and "quality assurance" are done by different groups. [Needless to say, those houses deliver without warranty.]
https://www.cs.utexas.edu/~EWD/transcriptions/EWD13xx/EWD130...
While I agree with this, in a lot of software there's more to verify than just being correct. Unless there's a separate and rigid UI/UX spec then there's also matter of things being intuitive to use etc. which may vary from person to person and the one making the thing might not have the same sensibilities as the users.