It's more like when you prompt the model with "be an assistant from the time of Shakespeare", you don't know if it'll imitate actual Shakespearean data in its t

It's more like when you prompt the model with "be an assistant from the time of Shakespeare", you don't know if it'll imitate actual Shakespearean data in its training, or the sea of modern human imitations or "fan fiction". There are various ways modern knowledge may have "snuck in" through data contamination. If we really want to know what a Shakespearean chatbot would have looked like, we need to cap the training data. Maybe in the future, using better mechanistic interpretability we can get around this, but not right now.