> Nobody forces me to modify a running system, though it usually is a huge time saver I won't dispute this fact, but it's not a principled way to work. The pri

> Nobody forces me to modify a running system, though it usually is a huge time saver I won't dispute this fact, but it's not a principled way to work. The principled thing is to have two separate phases, one for designing abstractions, another for using them. You can't prove anything definitively about things that are eternally open for modification.