How can we be confident about what we know - especially in an age of scepticism? This is the question that John addresses in this compelling talk on the 'Need to Know'. You would think that Christians are on the back foot here because we rely on faith to know - but John turns the tables on the sceptics and proves that 'radical doubt' is everybody's lot in life. Strangely this leads to the only conclusion - 'radical faith' must match radical doubt. The Q and A session at the end is a treasure.