I think Mr. Saletan has made some important points here. This discussion underlines a common tactic of the in the abortion debate: one side asserting that their beliefs are scientifically confirmed, that they are merely making a scientific claim when, in fact, they are making a moral or philosophical claim. "Science tells us that life beings at x", therefore, the speaker's beliefs are sacrosanct. But it always ends up as another disputable belief claim. People try to leverage their opinions with the supposed irrefutability of science; but the consequences of any scientific claim is a matter of philosophy.
I'm surprised Saletan didn't point out that, however much what these authors say may be scientifically true, science cannot make any prescriptive claims. Consider this:
What makes you a human being, they argue, isn't a soul, but "a
developmental program (including both its DNA and epigenetic factors)
oriented toward developing a brain and central nervous system." They
believe that this program starts at conception, and therefore, so does
personhood.
Is the fact of a developmental program that is oriented towards developing a brain and central nervous system something that can be scientifically, experimentally tested? Yes. Is the belief that this program begins at conception something that can be scientifically, experimentally tested? Yes. Does science assert any particular moral consequences from those facts? No! "[A]nd therefore, so does personhood" is a claim that has no scientific value; it is a purely philosophical claim. Like any other disagreement about abortion-- or any other moral or ethical dispute-- we are left merely with competing philosophical claims, and, as usual, one side claiming that "it is perfectly obvious that...." These two researchers are no different from any one else engaging in the abortion debate, save that they are trying the worn out tactic of asserting that their position has the "certainty of science."
Science cannot solve our moral disputes. I'm sorry. There is no Ten Commandments hidden in our DNA, no "fundamental, real morality" to be deduced from a GUT. Those who claim otherwise are either arguing in bad faith, as these two are, or are simply unable to deal with the fact that we will always be trapped in the muddle.
