What Does It Mean To Be Alive?

For centuries, stories about the origin of life have gripped us, while attempts to understand and define it have confounded us as for every metric we use to measure and qualify life, inevitably there’s some microbe or animal that doesn’t quite fit the bill. So, how do we answer this question and what does it mean to be a living thing anyway? Carl Zimmer, an award-winning New York Times columnist sought to discuss just that in his latest book - ‘Life’s Edge: The Search For What It Means To Be Alive’ - he joins Jonathan to discuss.