I didn’t agree to that, although I can see one place where I could be misread as doing so: “I would not deny that there was a human being in a certain sense (continuity) before the development of the nervous system, but whether or not the nervous system is morally significant has absolutely nothing to do with that.”

By that I meant to emphasize that it is _not_ substantively a human being – it does not have the characteristics that are normally taken as definitional of either human or being. Rather, _if_ it is allowed to develop, then _retrospectively_ there will be a connection with something that is a human being.

I’ve not used a definition remotely like “anything that exists” even if you have tried to press that onto my remarks.

If the scientifically evidenced existence of a fellow human being is not morally interesting to you, when it comes to the question of protection, then, there can be no common philosophical ground between us.

There would be nothing to hedge and nothing to balance, based on what you’ve offered, only your arbitrary sayso.

But earlier you had hinted that there was common philosphical ground and I’ve sought to demarcate it by first establishing what scientific eyes can indeed discern.

Unfortunately, now you’d deny even that much.

No, we never got that far. “Human” – yes. “Being” – like I said, it depends on your definition. For morally uninteresting definitions (“anything that exists”), sure. For morally interesting ones, no.

But you pose as if you can’t see the value of that scientific fact, that bright scientific line, when it comes to the philosophic question of moral obligation to protect.

You declared that you don’t value the human being as a human being. You value a subset of characteristics of the matured human being. Why, you haven’t bothered to say; you just pointed to a dictionary.

That was your starting line: an axiomatic belief which remains unsupported by your stated reasoning.

Exactly. I largely ignored your repeated presentations of the scientific evidence because we agree on the scientific evidence. What we disagree on is the implications of the scientific evidence, and in fact the scientific evidence has no implications without additional moral/philosophic assumptions. I’ve presented my moral philosophy on the subject and justified it in terms of things I value and that I fancy other people might value as well. You’ve blathered on completely oblivious to the fact that you’re making non-obvious moral/philosophical assumptions in addition to the scientific evidence. I’e tried drawing this to your attention but with no success whatsoever, and it’s not an effective use of my time to continue.

Severed skin has the same DNA as the individual from whom the skin was severed. An embryo is not part of his father nor of his mother but is a unique individual. That DNA is utilized by this living organism to self-integrate and direct his own development as a particular member of humankind. This is impossible for the severed skin — its DNA is not unique and skin cells remain skin cells — it is merely a part of a member of humankind. Skin cells (in cloning) might be closely analogous with sperm and ova — if you are trying to get from skin cells to the embryo to the “potential adult”, as it seems you are trying to do. But skin cells are not closely analogous with embryos just because of the fact of DNA.

I’ve discussed this only on the merits of the scientific evidence for a bright line. Not a moral line. A scientific line.

You depend on faulty analogies, Mark. The epigentic primordia is necessary for a nervous system and brain. That is also a line that is far more significant to sentience than your selection of a degree of development for transformation into a kind — that some point of maturation the human being transforms from something like a severed skin to something like a pre-adult person. In fact, you have now refused to selected a degree and have instead arbitrarily chosen a hedge that is about two decades prior to the emergence of an adult brain — and only about two weeks after the bright line at fertlization.

The hedge is arbitrary because sentience is not the bright scientific line even if it remains your vague moral line.

What purpose does the hedge serve if not to err on the side of moral obligation — to be safe rather than sorry?

Determined, yes – the DNA is sex-specific from the beginning. Meaningfully present, no.

CO: “And I have merely pointed to the scientific evidence as producing a bright line that a human being exists — and not merely possesses DNA.”

No, you’ve insisted that there’s a human being present, and you’ve insisted that the scientific evidence proves it, but you’ve never actually given an argument – I had to bring up the DNA for example.

CO: “As already discussed, skin cells are analogous with sperm and ova, not with embryos.”

By what criterion and why is it important? In particular, one usual objection to counting sperm and ova is that they don’t have a full complement of DNA (they’re haploid). But skin cells do.

CO: “If you would start “with sentience, period” then please point to that starting line rather than to a hedge.”

Why should I bother? If sentience is what matters and the hedge is adequate, that’s the end of it.

As already discussed, skin cells are analogous with sperm and ova, not with embryos.

If you would start “with sentience, period” then please point to that starting line rather than to a hedge.

You keep pounding the table about this, but you don’t say according to what criteria it qualifies. Three have been mentioned, and they don’t seem particularly morally salient, for reasons I’ve outlined.

CO: “Also, the distinguishing feature is not merely the possession of human DNA but the embry’s use of its own DNA to self-integrate as a living organism. The human DNA happens to be unique to that individual human being. So the embryo is of a kind — i.e. humankind — and an individual human being.”

It’s clearly alive and it’s clearly human to the extent of having distinctive DNA, but that’s a pretty limited extent and again you evade saying why it’s an important or morally salient extent.

CO: “If he lacked human DNA, his use of his DNA, and his life, then, the moral line for the rest of us would be moot.”

You keep assuming the conclusion: that there’s a “he” there that is like us in a morally salient way, and in particular a “he” that can “possess” something in a morally salient way. After all, a severed (human) foreskin possesses human DNA too, and we don’t view that as morally salient.

CO: “But you have conceded that you’d start with the mere potential for sentience, not at sentience.”

I don’t believe I have, or at least not in any sense that helps your case. I would start with sentience, period. I would think it prudent to hedge about that to include anything that plausibly might _be_ sentient. For reasons I’ve explained, I would specifically not seek to extend the hedge to include things that merely might _become_ sentient.

The embryonic human being is already a member of the human family. Not a potential member nor a potential human being. But a whole human being. That is a bright scientific line.

Also, the distinguishing feature is not merely the possession of human DNA but the embry’s use of its own DNA to self-integrate as a living organism. The human DNA happens to be unique to that individual human being. So the embryo is of a kind — i.e. humankind — and an individual human being.

If he lacked human DNA, his use of his DNA, and his life, then, the moral line for the rest of us would be moot.

You have suggested that sentience is another line, but one not so bright, which you value. You’ve not really explained why anyone else should value it as highly as you do.

Even sentience requires embodiment, as we’ve discussed.

You said: The fact that _some_ hedging may be prudent …

You said: The fact that _some_ hedging may be prudent doesn’t mean (i) that you can sensibly start anywhere else but at sentience, (ii) that conception can sensibly be regarded as anything but a hedge around sentience, or (iii) that hedging all the way back to conception isn’t pointless overkill.

But you have conceded that you’d start with the mere potential for sentience, not at sentience.

You have been reasoning through faulty analogies.

Just now you repeated the notion of the “potential adult” when I was speaking of the existing human being. You referred to possession of DNA when I was speaking of that particular human being’s DNA and his use of his DNA.

Yet, here you’ve used sentience as a starting place without anchoring it to the scientific evidence for the emergence of sentience nor to the potential of full-actualization of sentience. You haven’t pegged sentience to the particular human being’s use of his sentience.

The analogy of potential adult and potential sentience is inapt. A closer analogy is required — the existing human being who possesses uses his DNA as compared with the existing human being who possesses and uses his sentience.

How would you start with the emergence of sentience without starting at the bright scientific line of fertilization?

No sentient human being was anything other than a human being prior to developing and using his sentience. Fertilization is more than a hedge. it is a prerequisite.

Within your own stated reasoning, Mark, I did observe that conception would better serve the purpose of a hedge. But perhaps I misunderstand your purpose.

You seem to think that hedging “may be prudent” rather than a necessity, given your reasoning about sentience.

If prudence is the operative word, does that the idea of a hedge is “it is better to be safe than sorry”. Or “it is better to err on the side of moral obligation than indifference”?

Would it not be imprudent, i.e. overkill, to delay moral obligation where the life of an existing human being is already at stake?