(This is part of a list of bad arguments I heard at the Texas Freethought Convention.)

I save the worst for last: the pro-choice (Matt Dillahunty) vs. “pro-life” (Kristine Kruszelnicki) debate on Saturday. Poor Ms Kruszelnicki, a recently declared atheist who opposes abortion, was hopelessly outclassed and outgunned at every point, and relied entirely on bad arguments.

Dillahunty went first, and he staked out a clear and narrowly focused position: that the personhood or “human” status of the embryo/fetus were totally irrelevant to his argument, and that he was building his case entirely on the right to bodily autonomy of the woman. Even if the fetus was judged entirely deserving of consideration as a person (a point he personally does not accept), it would not matter: a woman must retain the right to control her own body.

So what does Kruszelnicki do? Announce right at the beginning that her entire argument was that the embryo is fully human from the instant of conception, and therefore abortion is wrong. She made it clear that she opposes a whole gamut of basic rights: birth control methods that prevent implantation are wrong, because that’s just like strangling or starving a baby; no abortion in cases of rape or incest, because the baby doesn’t deserve punishment; she did allow for abortion in cases that threaten the life of the mother at times before fetal viability, simply because in that case two fully human lives would be lost.

So right from the beginning she was building an argument that entirely ignored anything Dillahunty would say, while Dillahunty would spend the next hour and a half directly refuting the relevance of her case. It was a humiliating rout.

What made it worse, though, was the quality of Kruszelnicki’s arguments. Would you believe that at one point she showed us a grisly video of the outcomes of abortions? Bloody severed body parts, slack gooey limp bodies, puddles of blood with twitching bits of flesh, that sort of thing. There were several different reactions from people I talked to afterwards. Many were just repulsed, and had closed their eyes or walked out of the room when it was shown (oh, yeah, that was an effective tactic in a debate: disgust the audience). Everyone was appalled that such a blatant and logically irrelevant emotional appeal was being made; that’s another brilliant move, insult the intelligence of the audience by assuming that they won’t be able to detect the patent emotional manipulation being practiced.

I had a somewhat different response. I’ve seen surgeries (and done surgeries on animals), and let me tell you, they are unspeakably violent: bodies being cut into and violated, bones broken and cut, torsos cracked and wrenched open — from a naive perspective, every surgery, no matter how benevolent, is terrifyingly brutal. I was unimpressed by a movie that showed the reality of our biological condition. We are full of blood and slime and squirming guts and twitchy tissues, and you aren’t going to sway me by telling me that an invasive surgical procedure is messy and gross.

But the part that really annoyed me is that she repeatedly announced that SCIENCE had declared the conceptus at the moment of fertilization to be fully human. To demonstrate this, she cited several familiar names: O’Rahilly and Moore, for instance. These are people who have authored descriptive embryological texts that take a phenomenological approach, describing the different stages of development. They are not sources that are good for understanding mechanisms or processes, and they definitely do not represent a deep modern understanding of the progressive and emergent properties of development. What she was relying on is that these kinds of texts will state simple facts, like that fertilization produces a zygote with the complete human genetic complement, which they’ll summarize with some shorthand statement that it is a human embryo (rather than a mouse, or a frog, or a fish). From this, the anti-choicers have spun out unwarranted extensions of reductionist statements to claim that they are making definitive statements about personhood or that they’re discussing something as complex as humanity rather than a minimalist statement about genetics.

And they’ve been doing this for decades. That Kruszelnicki is an atheist does not change the fact that she’s using a ridiculous canard that has similarly been used by religious anti-abortionist zealots; she was basically lying about what deveopmental biologists say, and trying to use an unfounded argument from authority as the basis of her debate performance. Bad move.

I actually got to ask her about that. I told her that she was using old descriptive sources and inappropriately extending the implications; I asked her if she had more modern sources with a little more depth, and she waffled and told me that she had lots of recent papers on the subject and that embryologists all agreed on this point (obviously, no they don’t) and she waved a few papers in my direction.

I went up to her after the debate and asked if I could see those sources she waved at me. Suddenly, she couldn’t find them any more. She mumbled something about a “white paper” by an author whose name was unclear, and that she’d find it for me later. She never did, although she and I were both there at the conference for at least 3 more hours. I also mentioned that a “white paper” is not the same thing as a scientific reference; it would be an advocacy statement from an organization with an agenda, and would have very little weight with me.

Here’s the truth: SCIENCE does not make a definitive statement about the moment at which personhood is acquired. It is a product of a complex process with multiple inputs and interactions and no sharply defined transitions that can be pinned to anything as difficult to define as consciousness, identity, and independence. All we can say is that none of those things are there at conception, and all of them are there are sometime after birth, and that anyone who tries to tell you that they are all there unambiguously at some discrete instant in development is lying to you.