Uncertainty in Essay Writing: How do I know I will find a good argument? I have a few things that I would like to explore for my Masters thesis. However, I don't know yet whether I am good at this kind of topic, its more historical than what I am used to etc.

But my question is this:

How do people settle on a research question they haven't really explored yet, but then also know that they will be able to have something (more or less substantial) to argue for / to contribute once they are in the topic?

I feel like have an interesting topic, but I have no idea yet what I want to argue for or whether I have anything to contribute yet.
Simple: You start exploring several ideas, gathering references, learning how the attempted solutions work, searching for possible extensions/alternative approaches.

As Edison said: "Genius is 1% inspiration and 99% perspiration". You'd have to put in the "perspiration" part to be able to see the "inspiration" spark. Or, as Pasteur stated it, "Chance favours the prepared mind".