On The Point, Mindy Todd talks withAuthor and philosopher Tom Cathart about his new book “The Trolley Problem, or Would You Throw the Fat Guy Off the Bridge?” and about how jokes can illuminate philosophical ideas. Cathcart has written and co-authored several books, including the New York Times bestseller Plato and a Platypus Walk into a Bar, another exploration of ethics, intuition and logic. He's also had a career in health care, including directing a boarding home for people with HIV/AIDS in Maine.