As you try to model a larger domain, it gets progressively harder to build a single unified model. … These subtle polysemes could be smoothed over in conversation but not in the precise world of computers. … Time and time again I see this confusion recur with polysemes like “Customer” and “Product” … In those younger days we were advised to build a unified model of the entire business, but DDD recognizes that we've learned that “total unification of the domain model for a large system will not be feasible or cost-effective”