| The scientific definiton of alive is easy - something that contains cells. If you changed that definition to be 'anything that contains genetic material and can reproduce' to include viruses then whatever. The details don't bother me at all.
A fetus is alive, and even if someone is brain dead - there body is still alive.
But I assume you are trying to say that 'a life' and 'alive' are different things. What does and doesn't have 'a life' is an ethical question, some answer it using religion, and some answer it using science.
Religion tells us that any and every human life is important, because they have souls. Thus the fetus and the braid dead person still has a 'life'. Religion also tells us that animals do not have 'lifes' because they have no souls and were put on earth for the benefit of man.
Science tells us that the only real difference in humans and animals is level of intelligence - and so objectively, a human and an animal 'life' is equal.
It has also found that a fetus has no self awareness, no consciousness, no nervous system (thus can feel no pain), and so it is generally assumed that it doesn't have a life. |