I preach persistence a lot. It's important to be able to push through difficulties to get beyond them. But that doesn't mean that one wants to be blindly persistent at all times.
I was talking recently with a writer who was stuck, and not writing. In our meeting, I was stressing the importance of trying to write, and of starting to write. He wanted a method by which he could organize his collection of articles. "There are many different ways to organize materials," I said, "but none is definitive. What's important is to start writing." This answer was unsatisfactory to him, and he insisted on talking about how to organize his articles. I told him that had never seen a book on writing dissertations that talked about how to organize the research materials, and that every book on writing dissertations that I have seen talks about how important it is to start writing, and how starting writing begins a learning process that allows you to organize your thoughts and your ideas about material. This too was unsatisfactory. "I want a simple solution to organizing my material," he insisted.
A week later he wrote to me. "I'm still stuck. I haven't been able to organize my material, so I haven't written." I suggested again trying to start writing--however imperfect that writing might be. Again that suggestion was dismissed.
I know that everyone has a different way of working, and I recognize that having well-organized research at your fingertips can be helpful. But I also recognize that if you're stuck, trying something new can be very effective and very useful to helping move forward.
Albert Einstein reputedly defined insanity as doing the same thing over and over and expecting different results. If you keep working on a project and you keep getting stuck on a specific task, isn't it worth trying to approach that project from a different perspective? Doesn't it make sense to try a new angle from which to look at the project?
Persistence need not manifest as blind repetition of the same attempt. That may be simply stubbornness. We need to be able to learn and adapt--which are, in fact, some of the primary characteristics of basic intelligence--to be able to learn and adapt.
Edison was persistent, but he also knew that he had to try something new each time. Each failed lightbulb was a way not to do things. Maybe the tasks and methods of writing that lead you into stuckness are ways not to write.
When you're learning to play a musical instrument, or when you're trying to master an athletic skill, blind repetition is often necessary, and the repetition will lead to different results: you just get better and better at the skill you're trying to develop, if you're practicing diligently and your muscles and brain start to wire together new skills. The body learns to perform an action more smoothly and easily. I was giving a friend a guitar lesson yesterday, and I was stressing the importance of playing a given chord change over and over until the motions became smooth and even. With practicing a guitar, this works: playing the chords over and over, leads to different results over time; the practice leads our playing to become smoother and more facile. If repetition is leading to different results and you can feel those differences, then it hardly fits Einstein's definition of insanity, because the change comes, and so it is reasonable to expect--at least for a while--that doing the same thing over and over again will lead to different results.
But then again, those learning curves have their terminus as well. One does not infinitely improve as a musician or athlete, and the practices and exercises that get one to a given level of skill will not necessarily take one beyond that level.
A summary of my thoughts: persistence is important, but one needs to differentiate between persistence that is building skill and ability--useful practice and repetition--and persistence that is stubbornness--an unproductive practice in which one is stuck and not developing. One needs to be persistent, but one also needs to be able to change the angle by which a given project is approached, so that one is learning and adapting, rather than simply trying the same thing again and again, expecting different results.