2/4. Tis Folly to Be Wise. Some things are so Preposterous that only an intellectual could believe them. Francis Wheen examines how the cleverest people have been led into folly when their great brains somehow failed to sound the alarm. The eminent mathematician Michel Chasies fell for a con trick a child could have seen through and a 17th-century English scientist thought he had invented cloning 400 years early. Producer Jolyon Jenkins