A person who was born in August discovered Uranium-235.
 That is to say, the necessary and sufficient conditions under which a person at one time and a person at another time can be said to be the same person, persisting through time
  However, some people believe that other groups should be included; depending on the theory, the category of "person" may be taken to include or not pre-natal humans or such non-human entities as animals, artificial intelligences, or extraterrestrial life

