Perhaps I’m not understanding the question, but first and foremost, science is specifically not a belief system. My professors emphasized the fact that we were not to believe anything but rather accept or reject hypotheses based on evidence. Science is a tool. It’s a system of observing, recording, hypothesizing, testing, analyzing, and refining. If you’re asking when we will have refined everything to the point that there are no more questions, I don’t think that will ever happen. What I’ve found is the more questions you answer, the more questions you have.