In the June/July issue of First Things, Mary Eberstadt suggested commonality between pro-lifers and vegetarians that (she thinks) justifies closer affiliation. Think what you may about the thesis, on which I’m not sold, a subsequent letter from a gentleman named Gerald Lame brings us back to dualism:

So Eberstadt’s “moral traditionalists” are really animist-vitalists. And the news these pro-lifers have not yet heard, trapped as many are in their scholastic ghetto, is that the scientific theory of vitalism was found in the twentieth century to be false. The entire science of molecular biology is a testament to this fact. It turns out that there is no life principle. Life is a set of properties belonging to a suitably organized physical organism. These properties are the same for humans and nonhumans, for animals and plants. What distinguishes us is not some mysterious entity called human life. It is the structures of our bodies, especially our brains, and what they do. So a person is not a life. Animism is false. The mere fact that an embryo is alive does not mean that the person who might later arise from it is in any sense present. Life is not a proper object of sympathy.

He provides insufficient evidence to confidently declare him guilty of the practice, but Lame appears to be of the sort who extrapolate from mechanical understanding inappropriate philosophical lessons. He relies on “personhood” as something outside of biology and “life” but doggedly stops short of the next step into mire. If “life is a set of properties belonging to a suitably organized physical organism,” then one could define “personhood” as the combination of those properties with a genetically unique organism. Lame must inevitably fall back to the old argument about consciousness.
The pro-life argument, especially in a theological milieu, is that biological life and spiritual personhood are inextricably linked. Not unlike an aborigine believing that a photograph steals the soul, Lame implies that describing the biology negates the person. Accuse whomever he may of intellectual ghettoism, the track in which his argument lies is well traveled and fraught with moral pitfalls.
For example, in a previous paragraph, he describes the biological process of pain and notes that young fetuses are incapable of feeling it. But if opposition to killing a human organism is essentially a question of suffering, then inducing euphoria prior to ceasing the flow of impulses that animate a biological construct in the form of a human being would alleviate “moral intuitions” that even a person is “a proper object of sympathy.”