it's pretty clear in the real world what is and isn't a separate human. i can't hang out and play paddycakes with a bunch of barely differentiated cells in a womb. it's like calling our gut bacteria a separate being because they have their own functioning processes. some even argue that gut bacteria have some sort of community sentience, but even that doesn't make them a separate being with any claims at all on the human's body.

You must not mean "separate human" in the sense that biology does (because a distinct individual of the species homo sapiens exists from the moment of conception). What does "human" in this discussion imply if not "distinct individual of a particular species"?

it's 'separate human' whether you're speaking in terms of biology, sociology, politics, or anything else. biology happens to be the most brutal of these, considering human only those who reach viability, which for humans is long after birth unlike most animals. again, a group of cells doesn't an individual make.

I must be misunderstanding something. Are you saying that a one-week post-birth child is still not a separate human from your perspective because they are not "viable" yet?

you were making an ontological claim, which simply doesn't hold true in any practical or reasonable sense, in any and all domains.

then, i put forth a separate observation (perhaps too tersely and obliquely) that biology is the most brutal (ultra-objective, yet ultra-complex) and so the least reasonable domain to be employed in pursuing your line of reasoning (which is wholly subjective and cultural).

biology isn't subject to human reasoning, emotion, or culture, which is where ontological arguments like yours squarely reside.

Yes, I assumed that since we can talk about categories and kinds we must be able to talk about a shared truth based in objective reality. Either "human" is a category we can talk about which is based in objective reality (and our understanding of that objective reality in biology, physics, and metaphysics) or we're not going to make any progress because we're discussing "taste" using the language of "truth".

To put it another way, either there's something objective which can be said about dropping children off of bridges in the moral realm related to bodily autonomy and our understanding of the duties and rights around bodily autonomy or else there isn't an objective moral realm. I presume, from your previous comments that you hold that there is an objective moral realm. Did I mistake your meaning?

yes, objective. bodies (i.e., independent beings) are required to invoke bodily autonomy, which brings with it the direct corrollary that non-bodies cannot invoke bodily autonomy. that's rational and objective, as in, it's beyond culture, beyond 'taste', towards 'truth'.

you countered with a subjective opinion hanging off an ultimately irrelevant legal triviality (that's also cultural, not objective).

The child in-utero is most certainly an independent being (or else the mother is not unless she's living in a universe she created herself ex nihilo). Is there some way to define "independent" that isn't driven entirely by subjective desires for one outcome or the other? Or must we leave bodily autonomy as being too subjective a principle?

a clump of fetal cells is the textbook definition of dependent and inseparable. you're otherwise projecting what they might become if everything goes well, not objectively perceiving what they are in the present. if we projected every human that way, we're all dead, and therefore worthless.

neither our subjective nor objective experience of those cells today is equivalent to that of any human being around us. you just can't get to the conclusion you want with only biology and objectivity, because your key premise is neither an objective nor a biological axiom.

A zygote is most certainly independent of the mother in the sense that the child and the mother are distinct members of the species. The child is not a part of the mother, but an independent (distinct) entity. The mother and child are distinguishable by biologists, by information theorists, by Thomistic philosophers, and by nutritionists in the south of France.

The child is most certainly dependent on the mother in the sense that this distinct, independent member of the species Homo sapiens cannot survive without constant support from the environment (another living person) that the child finds themselves dependent on. They are, as you point out, inseparable. But even birth won't solve this problem. From a societal perspective, even adulthood won't solve this problem for 99.999% of the human race.