A first-century B.C. Roman poet and philosopher, Lucretius was worried that our fear of death could lead to irrational beliefs and actions that could harm society.
The quest for immortality is as old as humanity itself, but the prospect of being able to copy the neural networks of a person's brain shifts the pursuit of perpetual life into the digital world.
Different cultural groups respond with numerous, often conflicting, answers to questions about life after death. An expert explains the Christian idea of heaven.
Some scientists claim a pill that would have us living healthier lives for longer is less than a generation away. But many philosophers argue extended life may not be as good as it sounds.