John and Ken start by trying to get their heads around the concept of evil itself. They begin by considering evil actions and move on to evil people, but each time they end up with the same unsatisfying and circular conclusion: that, in its simplest form, evil is about doing ‘bad’ things and that people do ‘bad’ things because they’re evil. But who decides what is bad? Is there some universal ‘evilness’ inside us that can be measured?

Professor Baron-Cohen offers one solution with his ideas of ‘empathy.’ ‘Evil,’ or as he likes it, ‘empathy erosion,’ can actually be measured, both directly through brain scans, as well as through cognitive testing. What he finds is that the level of empathy we have is normally distributed in the population.

Does that mean some people are naturally more evil than others? Professor Baron-Cohen argues that ‘evil’ is an unhelpful term to use in this context, because it carries philosophical connotations outside the realm of science. A better term would be ‘cruelty,’ which denotes actions carried out with diminished empathy. He says that a propensity for cruelty is indeed found in some people more than others, but not necessarily in direct proportion to our levels of empathy.

To demonstrate this, he cites the example of autism. Whilst both psychopaths and those with autism are severely lacking in empathy, it is only the former who are inclined to act cruelly. Autistic people tend instead to withdraw from action.

In our society we treat severe autism as a disability. Should we apply the same logic to psychopaths? The final segment of the show deals with how we should apply the theory of empathy to our lives. Are we really justified in punishing psychopaths for killing? Is it better to have more or less empathy? Can we develop empathy? Tune in to find out.

• Roving Philosophical Reporter:  Caitlin Esch finds out how empathic her friends are, using a test developed by Professor Baron-Cohen himself. She discovers that although most people think they have a great degree of empathy, they tend to overestimate themselves. She is joined by Psychiatrist Thomas Lewis.
• Sixty Second Philosopher: This week our Sixty-Second Philosopher provides us with a terrifying tale about why you should never trust your boss…