UPDATE: An embryo exists in two stages — dependent then independent. Dependent means that it cannot survive without the mother. Independent means that it can survive without the mother. An embryo is not independent until it has an active brain. ¶ Now, a half-built car is not a car. Likewise, a half-built person is not a person. Therefore, a person without an active brain is not a person. Note that we don’t have to prove when an embryo becomes a person. We just have to prove when an embryo has not become a person yet.