You may remember from my last post that I was struggling with how to justify my opposition to abortion in a non-religious manner. I have to express my immense gratitude to my sister (who studying to be a midwife and has studied philosophy and ethics) who took the time one weekend when I was visiting to spend over an hour talking me through a purely philosophical, definitional, and medical reasons to oppose abortion. It has been almost a month since I talked with her (I so should have written this sooner!), but I wanted to summarize what she told me. Any mistakes here are purely ones with my memory since she explained it to me with a great deal of clarity and charity.
To start, we need to define the word "life". Since "murder" is the taking of a life, then if abortion is murder, the baby must be alive. Previously, I had only ever heard opposition to abortion based in the realm of ensoulment. But, as I said before, this is nothing that can be proven in any sort of logical or objective manner and is therefore something that must be taken on faith. However, if we can define life in an objective and measurable manner, then we will have something that can be used in a more scientific manner.
So, what makes something alive? Well, first off the object being talked about must have an identity of its own. Note that this does not exclude symbiotic organisms or parasites. While a symbiotic organism or parasite relies on it host to remain alive, it is separate from the host. Also, please note that a parasite is not necessarily bad despite the negative connotations that have come to be associated with the word. A fetus fits this description. The mother's body creates a sac to keep the fetus safe from the body that might otherwise attack it as a foreign organism, which would mean that the fetus is separate from the mother's body. Couple this with the fact that if you were to check the DNA, which is a combination of the mother and father’s DNA, the baby is undoubtedly something distinct from the mother.
Secondly, something that is alive must maintain homeostasis, which is defined as
So the question is whether or not the fetus can maintain its own internal equilibrium. The body of the fetus does maintain itself in a state of equilibrium within its environment inside of the mother, so yes, it fulfills this qualification as well.
Third, something that is alive must be able to grow in a manner that is not simply adding outside things onto itself. For example, if I were to build a structure and then add onto it, that does not make the structure alive because it is being added onto, not growing. A fetus, on the other hand, has to grow through the process of mitosis which the process through which life grows. Hence, the fetus fulfills this part of life as well.
Fourth, something that is alive must be able to produce energy through the metabolization of chemicals and energy. The fetus does this through the placenta and umbilical cord. So, this part of the definition of life is fulfilled as well.
There is more, but these are the main ones. Because each of these properties, which are integral to the definition of life, we can safely say that the fetus is alive and that abortion is murder since murder is the deliberate taking of a life.