Out of sight, out of mind. “We know startlingly little about life at the bottom of society,” notes Matthew Desmond, a Harvard sociologist, in a new journal released on Tuesday by the Russell Sage Foundation — one of the nation’s pre-eminent research institutions on social policy — that explores severe deprivation in America. The American antipoverty strategy, so focused on choosing between good and bad guys, those worthy or unworthy of public assistance, is shaped by this ignorance.