If I just 'sit back and think' I wouldn't use Emacs at all. I believe at least for Emacs people use it because it's an interactive environment like Slime. With

If I just 'sit back and think' I wouldn't use Emacs at all. I believe at least for Emacs people use it because it's an interactive environment like Slime. With this kind of interactiveness, I can think by playing with the code. Just like sketching with a pencil instead of a pen. Most of the time 'sit back and think' doesn't work because if your business model is dynamic you have to break your existing design and refactor, unless you are just solving a problem in a small generic domain. At least for OO languages. That's something IDEs are used for.