This is, or at least is likely to become, an important moral issue, so I want to discuss it here. We recognize "persons" as having rights under the law and in custom. We acknowledge that they are entities in their own right, and not merely tools or toys to be used -- that's what it means to be a "person." An inanimate object, a plant, or even an animal is not regarded as having the same rights as a person, even if cruelty to animals is frowned upon. But what exactly IS a person? We think of this as synonymous with "human being," but let me present four hypothetical circumstances in which it could be argued that entities that are definitely NOT human beings might be considered persons, or in which the concept of a "human being" becomes fuzzy. 1) Extraterrestrial intelligence. Say a spaceship lands on Earth and intelligent aliens reveal themselves. These creatures are certainly not human. Are they persons? Should their rights be respected under the law? Should we regard them as beings like ourselves, or may we use or destroy them like things? 2) Human genetic engineering. This is definitely coming. At first, it will be used to treat genetic diseases and possibly cancers, but it's a short step from there to improving human intelligence, overall health, and physical abilities. A century from now, there may be human beings adapted to life in free-fall, or with wings, or with genetically-engineered perfect recall, or other things hard to imagine. At what point does this fiddling cross the line so that we are no longer dealing with a "human being," and at that point, are we still dealing with a person? 3) Animal genetic engineering. This may or may not happen, but anyone who has read David Brin's "Uplift" science fiction novels will recognize what I"m talking about. Suppose that chimpanzees, dolphins, parrots, gorillas, or other fairly intelligent animals are modified to give them full human-scale intelligence. Would such beings be considered persons? 4) Artificial intelligence. This field of technology is advancing very rapidly, and will have economic consequences leading to radical change, but suppose that it goes so far as to generate artificial intelligence that is human in scale and self-willed. Would such a robot be a person? Discuss.