Some notes on Marquis:
He thinks whether abortions are wrong or not does not depend on whether any fetuses are
He thinks to understand whether it’s wrong to kill fetuses, we should think about why it’s wrong to kill us. He thinks the best explanation of why it’s wrong to kill us is this: (a) we have valuable futures and (b) killing us deprives us from experiencing these valuable futures.
If (1) fetuses have valuable futures like our valuable futures, and if (2) it is wrong to deprive something from experiencing its valuable future, then abortion is wrong, he arguments (because abortion prevents something that has a valuable future from experiencing its valuable future).
We can prevent the argument like this:
1. Fetuses have valuable futures like our valuable futures.
2. It’s wrong to prevent something from experiencing its valuable future, or deprave them from that valuable future.
Some questions about the premises.
Regarding (1) we should think about what our futures are like and why they are valuable. We should think about how fetuses futures’ are similar and different from our futures.
Although both fetuses and us have futures – in the sense that there is (hopefully) good stuff that we will experience – there is a difference between our futures in that we are currently, consciously aware of our futures and are looking forward to them. We have plans and hopes for the future; fetuses do not. Maybe that makes a difference. Maybe that means that fetuses do not have valuable futures that are quite like our’s, and maybe they are not (so) valuable because of that.
Regarding (2), we might wonder what implications this principle has for contraception and even abstinence. One might reply that birth control and abstinence do not prevent something from experiencing its valuable future, or deprave them from that valuable future, because what birth control does is prevent there from being that something or someone. One might reply that there are things like this: interesting metaphysical “objects” that consist of an-egg-and-the-sperm-that-would-fertilize-it and that these objects have valuable futures which contraception prevents from being experienced. If so, then (2) implies that contraception and abstinence are wrong. You might think this is a false implication of (2) and so the argument is unsound.