Kari Weil, the University Professor of Letters, was a guest on WNPR's "The Faith Middleton Show" to discuss how our evolving understanding of animals should affect how we treat them personally and professionally. They began by discussing the announcement that Ringling Bros. and Barnum & Bailey would stop using elephants in their circus performances within three years. "I think there is a fine line between use and abuse," said Weil."I don't think all use is abuse. I think animals depend on us, we depend on them. We can use certain animals for certain things, but when we're down to exploitive techniques like bull hooks…