A more interesting question would be why software programs, or databases, age and die. At some point, their own size and complexity will make them hard to change, and they will be left to slowly die.<p>When I was younger, I wanted to live forever. But now I came to believe that dying is actually good, for a similar reasons. As we age and learn, we become experts at many things, but at the cost of flexibility and speed of learning (this is actually expressed in myelin coating of synapses). So we need to have next generation of people starting from scratch, questioning everything, otherwise we would be stuck with the old ways of doing things.<p>So perhaps aging and death is an evolutionary adaptation, to changing conditions in our environment.