For natural selection to have generated such a diversity of living things on earth, time and the mortality of every individual organism to assure the future survival of species are both required. We propose a simple but challenging definition of life as the property of an organism that possesses any genetic code that allows for reproduction, natural selection, and individual mortality.

This definition underscores the need to protect the unknowability of future life forms. The randomness of pre-adaptive mutation, the surviving genomes, and the phenotypes of our species in the future cannot be known with certainty, nor can we know what species will replace us, if any.

Our definition is more expansive than NASA’s, which describes life as “a self-sustaining chemical system capable of Darwinian evolution.” AI robots would not fit into our definition because human beings can control all aspects of computer functions. There is no uncertainty, nor unknowability, with AI robots. AI-based human robots can be programed to replicate themselves and even can be programed to terminate. However, robots do not sense “mutations” or engage in any natural selection process and, therefore, would not meet our criteria as “living.”