Melvyn Bragg and guests discuss the insight into our relationship with the world that Immanuel Kant (1724-1804) shared in his book The Critique of Pure Reason in 1781. It was as revolutionary, in his view, as when the Polish astronomer Copernicus realised that Earth revolves around the Sun rather than the Sun around Earth. Kant's was an insight into how we understand the world around us, arguing that we can never know the world as it is, but only through the structures of our minds which shape that understanding. This idea, that the world depends on us even though we do not create it, has been one of Kant’s greatest contributions to philosophy and influences debates to this day. The image above is a portrait of Immanuel Kant by Friedrich Wilhelm SpringerWith Fiona Hughes Senior Lecturer in Philosophy at the University of EssexAnil Gomes Associate Professor and Fellow and Tutor in Philosophy at Trinity College, OxfordAnd John Callanan Senior Lecturer in Philosophy at King’s College LondonProducer: Simon Tillotson

Melvyn Bragg and guests discuss Nietzsche's On The Genealogy of Morality - A Polemic, which he published in 1887 towards the end of his working life and in which he considered the price humans have paid, and were still paying, to become civilised. In three essays, he argued that having a guilty conscience was the price of living in society with other humans. He suggested that Christian morality, with its consideration for others, grew as an act of revenge by the weak against their masters, 'the blond beasts of prey', as he calls them, and the price for that slaves' revolt was endless self-loathing. These and other ideas were picked up by later thinkers, perhaps most significantly by Sigmund Freud who further explored the tensions between civilisation and the individual.WithStephen Mulhall Professor of Philosophy and a Fellow and Tutor at New College, University of OxfordFiona Hughes Senior Lecturer in Philosophy at the University of EssexAndKeith Ansell-Pearson Professor of Philosophy at the University of WarwickProducer: Simon Tillotson.