What do we talk about when we talk about whiteness? Are ideas of race fluid? Are some Irish people still happy to think of themselves as "the blacks of Europe", as Jimmy Rabbitte put it? Irish Times resident philosopher Joe Humphreys visits the studio to grasp this nettle and a few other uncomfortable ideas we really should more think about.

In part two: Linda Doyle of Trinity College wants the arts and the language of arts to play a bigger role in science, technology, engineering and maths. She bats the idea about with Fionn and Laurence in the face of some opposition.

Plus, what to expect from the new season of hit podcast Serial.

‘Unthinkable: Great Ideas for Now’ by Joe Humphreys is available from Irish Times Books: www.irishtimes.com/irishtimesbooks