they made choices in their particular moment. we should be responsible for the world that they gave us the legacy they bequeathed us. for someone like ben affleck it means coming up in a moment of opportunity. it was made possible by generations of wealth opportunity, prosperity. it essentially allowed him to become the person he is. it's not just individual talent or gumption. it's the result of generations. >> who we are is cumulative from the history from which we come i wonder how much we don't know about slavery. and not just oh the white folks -- i mean us as americans. our inability to contend with it. when you think of what we know what don't we know that we should? >> that's a big question. >> i know. >> can you explain slavery in