Haldane and Lee (and George) and ensoulment

I'm not posting any really new material here, just summarizing what I have written in other posts.

John Haldane and Patrick Lee are probably correct in their criticism of Pasnau's application of Aquinas to contemporary embryology. (See their followup.) I'm not going to read those parts carefully. They are correct to emphasize that development (not just growth but organization/differentiation of organs) is caused by the conceptum itself, and not by something external to it. Development it is a natural operation of the conceptum.
You'll find the same sort of argumentation in the pieces written collaboratively by Lee and Robert George, and probably in George and Christopher Tollefsen's book Embryo (which I haven't had the chance to read yet).

But I would argue that development occurs in other animals as well and cannot be attributed to the rational soul alone. One cannot claim absolutely that a rational soul is present at conception, when the presence of a sensitive soul could explain what is taking place.

To clarify what I had written previously: I don't think that the medieval understanding that there is a succession of forms--vegetative, sensitive, rational--as the embryo is formed from without can be maintained. I use "sensitive"  here to distinguish the rational soul from the nonrational souls of other animals. Nor do I think one can rule out a priori with good reason that the rational soul is infused at birth. But one cannot establish the presence of the rational soul either, since there is the absence of rational activity (and the organs required for that activity). The conceptum does have the power in itself to generate those organs ("the brain and nervous system"), but this power in itself does not mean that it possess a rational soul, unless one argues additionally that only a rational soul can bring about the development of organs that are proportioned to the intellect, etc. But what does the rational soul as form of the body have in addition to what is possessed by a sensitive soul that could conceivably develop the embryo into a specifically human body? Even if it is the case that the human sense organs are very different from those of any other animal, this does not mean it is impossible for a sensitive a sensitive soul to generate those organs.

Still, a theological argument based on what the Church's teachings on the Incarnation can be made that the soul is infused at conception, but this will not convince non-believers. I tend to think that changing the laws regarding abortion on the Federal level will never happen. (And it seems unlikely to me that the Federal government will ever let this issue devolve back to the states.) With the refusal of traditional morality regarding sexuality and marriage, the culture and its institutions of many areas and states cannot but have abortion as a legitimate act for women. In those places, for a law against abortion to take hold, many other changes must be implemented. These changes are so great and encompassing that one can speak of the necessity of their people to be converted without exaggeration. Some states may be more sympathetic to stricter abortion laws, but their culture may be changing at a rapid places.