Recent advances in neuroscience have revealed that certain neurological disorders, like a brain tumor, can cause an otherwise normal person to behave in criminally deviant ways. Would knowing that an underlying neurological condition had caused criminal behavior change the way we assign moral responsibility and mete out justice? Should it? Is committing a crime with a "normal" biology fundamentally different from doing so with an identifiable brain disorder? John and Ken ask how the law should respond to the findings of neuroscience with David Eagleman, author ofIncognito: The Secret Lives of the Brain.