Doing a PhD is an iterative process of doing something you believe in, questioning your belief and adjusting what you do so that you continue doing something you believe in. This is similar to driving with a navigational app. You start with some route it calculated at first, but then some unexpected traffic starts to accumulate, and the app recalculates route for you. This happened to me several times so far during my PhD, and it’s happening right now as well.
cloudalion 