Few philosophers are compared to rock stars or TV celebrities, but that's the kind of popularity Michael Sandel enjoys in Japan.

The "Justice" course that Sandel teaches at Harvard University, where he is a professor of political philosophy, delves deep into some hard moral dilemmas we face in our everyday lives. It is said to be one of the most popular classes in the history of the prestigious U.S. academic institution — and it has been televised on the PBS stations.

That course has also inspired many people and sparked a boom in philosophy debate in Japan, thanks to it being broadcast on the NHK Educational channel from April to June.