Melvyn Bragg and guests discuss how we can know anything at all.
Paul Broks looks at the philosopher Ludwig Wittgenstein and the problem of 'other minds'.
Clare Carlisle grapples with Bishop Berkley's idea that objects only exist in our minds.
How can we separate real science from mumbo jumbo? Physicist Tara Shears investigates.
Barrister Harry Potter on whether we can believe our eyes.
Melvyn Braggs and guests discuss the history of ideas around love.
How should we love our children? Philosopher Jean-Jacques Rousseau had some great ideas.
What is love? Psychotherapist Mark Vernon looks at Freud's ideas on the Greek god Eros.
Giles Fraser discusses gene theory versus altruism with Tom Stoppard and Armand Leroi.