A new philosphical movement is gathering steam in Silicon Valley, one that promises immortality by using technology to solve the problem of death. This movement is led by Oxford philosopher Nick Bostrom. Professor Bostrom is the author of Fable of the Dragon Tyrant, the original manuscript of the modern immortality movement. It was published in 2005 in the Journal of Medical Ethics as a response to what Bostrom described as the absurdity of the inevitability of accepting ageing and death. Far from being a one-off, the Fable is one of the core texts that form part of a moral philosophy of the future of humanity called transhumanism. Adherents believe that we will achieve immortality by merging with artificial intelligence and becoming “post-human", and that the next step in our human evolution is nigh. In this series, technology reporter and psychologist Aleks Krotoski explores the frontiers of the extreme longevity pioneers. They've made their money in Silicon Valley. And with their technology solutions - PayPal, Facebook, cryptocurrencies - they've ushered in the world that we live in today, with all its unintended consequences. Some of them now want to solve the "problem" of aging, or even death, and they are making bigger strides than we may think. Can they? Should they? A Pillowfort production for BBC Radio 4 New episodes released Mondays. If you're in the UK, listen to the full series of Intrigue: The Immortals first on BBC Sounds: bbc.in/3WEQS5W