Doctor Who: The Keeper of Traken - Episode 115

What if we could create life from chemicals? What if we could reduce love to molecules, regrow new hearts from skin cells, or regrow new humans from cuttings, like plants? What if we could resurrect our ancestors, make ourselves immortal, or even grow younger? If these science fiction scenarios give you pause, you are a little behind the news. It's already happening, in labs all over the world.

The meaning of life used to be simpler. But it turns out we were wrong about a lot of the details. Some of the things biology has discovered recently still fit the original contours, allowing us to understand how once mysterious life processes actually work, often in surprising and ingenious ways that are more awe inspiring than the miracles they replace. Some of these discoveries render old meanings of life completely incoherent. And some will require us to re-imagine the meaning of life in yet to be determined ways.