More on abortion

Rick says, “I am inclined to agree with Eduardo that there is a difference -- one that is relevant to the perpetrator's culpability and deserved punishment -- between procuring or performing an abortion and maliciously causing the death of an adult.  True, both involve the deaths of human beings, and both are wrong.  But, it seems to me, the state-of-mind, or mens rea is almost certainly different (if only because the humanity of the victim, and therefore the wrongfulness of the conduct, is impossible to avoid in the latter situation).”

If I read this correctly, Rick is saying that the state-of-mind is different because the perpetrators do not recognize the humanity of the victim. I am wondering whether and how the criminal law ordinarily would take this into account. I would think that at most it would be a mitigating defense, if at all. I am wondering whether Rick is trading on the premise that a fetus is not a human being in the same sense as an adult or baby, and, if so, what that difference is. In other words, I am having trouble determining why first degree murder would not be appropriate (other than for prudential reasons) if the fetus were considered to be a human being in the same sense as a baby or an adult. Of course, one would not have to think that a fetus was the same as an adult or a baby to believe that abortion is a moral tragedy. Moreover, I can imagine some believing that the failure to understand that a fetus is the same as an adult for moral purposes is the product of the culture of death, an Augustinian failure.

Does the latter argument apply in another context? I am wondering about the significance to be attached to the fact that a high percentage of embryos do not attach to the uterine wall and perish. We do not consider this a world wide health crisis. Is this because we do not really think that embryos are human beings? What explains the lack of a sense of tragedy? How can Catholic teaching that a human being exists from the moment of conception be defended to non-Catholics without resort to Vatican authority?