Jonathan Cohn wades back into the discussion. He cites a biologist who agrees with him that the question of when a human organism’s life begins is unanswerable by science. He also argues that people who say that “life begins at conception” mean to affirm the normative view that human organisms should be protected from deliberate killing from that point onward, so the distinction I made the other day between science and philosophy is beside the point.
Biologist Scott Gilbert, in the cited discussion, is chiefly talking about what views different schools of thought have historically held about the moral status of human organisms in the early stages of life. Even in the section of his essay purportedly dealing with “scientific views” of when life begins, he is really discussing philosophical interpretations of the scientific data–and, I’m afraid, not discussing them very well.
So, for example, Gilbert discusses the position “that a single developmental moment marking the beginning of human life does not exist. Both the sperm and egg cells should individually be considered to be units of life in the same respect as any other single or multicellular organism. Thus, neither the union of two gametes nor any developmental point thereafter should be designated as the beginning of new life.” A person who objects to using the word “moment” to describe fertilization because it does not take place in an instant will have no problem with that first sentence. But sperm and egg cells are clearly not living human organisms, even though they are alive and human. None of the other “scientific” positions Gilbert discusses fuzz up the basic fact that when fertilization is complete and successful, a new living human organism exists.
Does that matter? Well, it’s not the core issue in the abortion debate, as Cohn says, but it is a distraction from that issue. We can’t discuss intelligently how to treat a living human organism in the embryonic stage of development if we’re using phrases that imply that human embryos aren’t exactly that. Cohn is right that the anti-abortion physicians in the ad he was attacking are using their prestige as doctors to build support for their normative views–a tactic that was by no means introduced to the abortion debate by their side. But on the specific point that Cohn attacked, and I defended, them on, they’re right: Conception marks the beginning of a human organism’s life.*
*It is also true that a conception-like event, such as cloning, can begin a human organism’s life.