Natural rights are rights inherent to human beings by the nature of being human. They were not created by a human legislator. They are objective in the sense of them existing regardless of our opinion about them.
Sounds like a claim.
So how does one go about finding out what these rights are? How do you "discover" them? And when you "discovered" them, how do you go about sharing those while supporting the idea of them being objective and not just your opinion?
Now, I am not saying that jusnaturalism is true. What I am saying is that jusnaturalism doesn't require God and that therefore it is possible to use it in an argument against abortion.
"Possible", perhaps.
But it seems to me that the vast majority isn't doing that at all.
And I say "the vast majority" out of some kind of intellectual honesty, because I'm not actually aware of any "anti-abortion militant/lobbyist" who uses such argumentation.
Now I have a question for you: If jusnaturalism is false, on what grounds can you claim that a law against abortion is unjust ?
Still not entirely sure what you mean exactly with "jusnaturalism" though.
But in any case, I indeed think such laws are unjust. And my reasoning for that comes from multiple angles.
The primary one being pretty much very similar to my reasoning that it's not okay to make a law that someone can be forced to give up a kidney to save someone else. It's not okay to "use" someone else's body against that person's will to keep someone else alive.
And that is "grounded" in pretty much the same way as my entire ethical framework. It's a combination of experience, learning from history, humanistic values (like human rights, equality, ...), knowledge about the world around us, etc...
And no, I do not agree that any of these things are "objective" in nature. Quite simply because "objective" literally means "independent of human thought", while things like ethical frameworks
literally only exist within human thought. Such frameworks and models,
literally develop over time. Our motals and ethical standards of today are not the same as 2000 years ago. They aren't the same as 500 years ago. Heck, they aren't even the same as only 10 years ago.
They constantly evolve and develop, as we gain more experience (like being on the receiving end of evil things instead of being the causal factor ourselves) and learn more things about the world (which helps us better understand the consequences of our actions).
You could ask the question "so what is the end goal then", because logically, if ethical models changes as we learn new things, then there should be some kind of standard in place against which things are evaluated.
A lot of theists will say that this standard is "God". And that's the angle the argue from and the baseline they will always circle back to during discussions concerning morality or moral values or moral evaluation (like abortion debates). Eventually, you'll always hit that wall of dogmatism where the "why" question is answered with "cause God decreed it so".
For me, the standard, the starting point, is the hypothetical utopian society in which I would want to live while not knowing in advance who I will be (in terms of ethnicity, religious/cultural background, sexual orientation, etc).
So my moral evaluation reasoning centers around "does this take us closer or further away from that utopian society?", and I do my best to really explore that. So in other words, it is NOT based on certain "decrees" that MUST be upheld at all times. It's not a black and white world that you can fit into one line rules like "MURDER IS WRONG MMKAY". No, there's always context and implications.
This is why it's so hard for me to discuss abortion with theists. That dogmatic wall that can't be torn down.
That's the thing... if you go about trying to build an argument against abortion without such dogmatic black and white "decrees" (and thus where the
logic in an argument must be universally applicable - otherwise it's special pleading), you end up in a hypothetical world where it's okay to knock someone out in the streets to take his kidney to save the life of another person.
EDIT: well, this turned out quite longer then I expected. I went on a roll there a bit, sorry. I hope I made some sense to you.