David Chalmers is credited with setting the terms for much of the work done in the philosophy of mind today when he posed the 'hard problem' of consciousness: how does matter, which is fundamentally inanimate, give rise to or interact with consciousness, which is qualitative and phenomenal - always a 'what it's like'? His most recent book, Reality +, is an investigation of the possibility that our entire experience could be an illusion.

Iain McGilchrist is a literary scholar turned psychiatrist whose 2009 book The Master And His Emissary developed the 'two hemisphere' model of the brain and cognition according to which the left hemisphere is rational, precise, but limited, and the right hemisphere is intuitive, creative, and expansive. Starting with this model, McGilchrist went on to analyse nothing less than the rise and fall of civilizations in terms of the interplay between these two aspects of human nature. His new book The Matter With Things goes even further, developing the hemisphere model into a means for explaining our basic relationship with reality - and suggesting ways it could be improved.

David Chalmers and Iain McGilchrist expound, explain and defend their work to Christopher Harding.

Produced by Luke Mulhall