Oh, good, impatience is a tough one so you are fortunate
Anyway, the problem with all your beautifully structured arguments, as I see it, is that they seem to ignore the fact that they are talking about
one thing.
The words you use: zygote, blastocyst, embryo, fetus… all of these are just words describing the stages the
one single entity goes through, just as baby, toddler, tween, and senior describe stages
the exact same entity goes through if the entity survives all the previous stages.
It’s not like there is some
thing called a zygote; zygote describes a
stage of development of a single entity which will go through many such stages.
Take me for example. 60+ years ago, I was at the stage of being a zygote, and that which is called a zygote at that point was me. That zygote grew until it entered the stage where it is called a blastocyst, but remained me, and I was called a blastocyst. The process repeated through all the stages we have named, and I was myself during all of them.
I have gone through a number of stages: zygote, blastocyst, embryo, fetus, baby, toddler, child, tween, teen, young adult, adult, middle-aged, and now, well, AARP informs me I am eligible to join, so I guess I am a senior
I came into existence when… when… when the stork picked up its carry bag and deposited me in a cabbage patch. (I know it’s different for other people, but that’s what my mother told me, and I am sticking to it!!!)
(I should have thought through this example a little more…)
Two things came together, melded, and became one thing. That one thing went through the normal process each of the members of that species goes through until the process is interrupted, which causes death.
Two things came together, melded, and became one thing. That one thing went through the normal process each of the members of that species goes through and throughout that process, it was the same one thing, me.
(continued below)