Abortion is murder!
How do you know that?
An unborn child is alive, and distinct from the womb of its parent. It's an individual life, and it's murder to kill it
Ok, let's break it down one step at a time
When an egg is fertilized, it is a living human being at that point
Fertilized eggs can take a day or two to implant. 50-80% never implant and die off naturally
Once implanted, if it survives, it can't yet be defined as an individual, because it still has a few days before gastrulation, which is the point at which it may divide into twins, triplets, etc. (If you believe in the concept of a soul, it would be difficult to make a case for a soul being present prior to gastrulation)
Being biologically alive and distinct is not enough to claim murder, because then killing a houseplant or pest would qualify as murder.
It's because it's human
If we're going to say this, then we need to be precise. Generally when we say something is human, we are talking about personhood, right? It's not enough that we have genetically distinct tissue of a homo sapien present. Otherwise a transplanted liver would be a distinct human.
Yes, it's a person, with the right not to be killed!
Ok, that's the claim, but we need to establish that it's rooted in evidence
We can't define a person by the ability to think unless we consider someone in a vegetative state non-human. And a fetus has barely any sensory perception or cognitive capabilities let alone the ethical awareness that would demonstrate any sort of personhood
Well why not at the point of viability?
Viability isn't a bright line either, since it is a moving target based on medical technology and individual conditions
The same problems would occur in every other biological metric. Personhood simply does not have a clear biological definition
At most biology suggests that there is no evidence a fetus is anything beyond tissue with the potential to eventually become something we will define as a person based on our own definitions of personhood
My beliefs and morality say it's a person and that abortion is murder
Yes, and for some people the actions they will want to take for themselves will be rooted in their religous beliefs. That's fine.
But we must not build public policy on religious belief alone
Ultimately science can tell us about reality, but it does not claim to tell us what we should do based on that knowledge
Let's talk about the ethics of abortion then: