Ethical policies for practices such as abortion and embryonic stem cell research should, of course, be well justified. But how does one justify that activities involving the destruction or killing of human embryos and fetuses should be allowed? How does one justify that they should be banned?
Just because the issues are so sensitive and important, they awaken a desire to find the absolutely conclusive justification.
The questions arouse our metaphysical aspirations. Ethicists who discuss them can sometimes sound like the metaphysicians of the seventeenth century who claimed they had conclusive arguments that the soul affects the body, or that it absolutely cannot affect it; who thought they could prove that God is the soul of the world, or that such a view detracts from God’s perfection.
Since both parties claim they have absolutely conclusive proofs, it becomes impossible to exhibit even the smallest trace of uncertainty. Each objection is taken as a challenge to prove the superiority of one’s own proofs, which is why metaphysical debates often resemble meetings between two hyper-sensitive querulants.
This is how I perceive many of the arguments about the embryo’s “moral status,” which are believed to provide conclusive evidence for or against moral positions on abortion and embryonic research – based on the nature of things (i.e., of the embryo).
Others, who want to reason more rigorously before drawing conclusions, instead scrutinize the arguments to demonstrate that we haven’t yet found the metaphysical basis for a policy (you can find an example here). From metaphysical dogmatism to metaphysical pedantry.
The metaphysical vision of an absolute path through life does not seem to give us any walkable path at all. It does not even allow meaningful conversations about what we find sensitive and important. But isn’t that where we need to begin when we look for a justification?