I really like the idea of bounded contexts and aggregates in theory. What I still don't understand is how defining them can be feasible at the beginning of a pr

I really like the idea of bounded contexts and aggregates in theory. What I still don't understand is how defining them can be feasible at the beginning of a project when you have too many unknowns (some of which are unknown unknowns). I am a DDD noob (currently reading the book Domain Modeling Made Functional), but maybe someone can elaborate on how one's supposed to make such decisions when there's plenty of uncertainty.