Because introducing new words with commonly agreed definitions won't help. It would go like this: life_prolife = life begins at the conception. life_prochoice

Because introducing new words with commonly agreed definitions won't help. It would go like this: life_prolife = life begins at the conception. life_prochoice = life begins at week 20 of the pregnancy (as an overly simplified example for the sake of argument). Pro life: it is wrong to kill anything that has life_prolife. Pro choice: no, it is only wrong to kill anything that has life_prochoice. It is, at least under some circumstances, ok to kill something that has life_prolife but not life_prochoice. So of course we haven't resolved anything (which I think is your point). Rather, we have moved the discussion to which definition is the one that is relevant to use when we discuss the sanctity of life. And that is a discussion about semantics.