There are two assumptions that the Abrahamic faiths make regarding fetal development:
- There is a soul.
- The soul enters the zygote at conception
What is the soul?
The attributes most commonly assigned to soul are the mind, the conscience, the will and the emotions.
The Search for the Soul:
Dr. Duncan “Om” MacDougall performed an experiment to determine the weight of the soul. He weighed his subjects at the moment of death and found that the soul weighed 21 grams. There is a problem however. He only had six subjects. Of these, only one lost 21 grams upon death and stayed at the new weight. He dismissed two of them due to technical difficulties. Another lost weight and then gained some. The last two lost weight and later lost more.
Modern neuroscience is exploring the age old question of psychophysical dualism, i.e., is there a soul? It has been found that consciousness, thoughts, behaviors and emotions can be predicted by the brain area that has been activated.
Tests of emotional regulation have shown that the inhibition of emotions is performed by areas in the prefrontal cortex. A brain region corresponding to the sense of self has been located in the prefrontal cortex. Damage to the anterior prefrontal cortex in children affects their ability to develop moral reasoning.
Many experiments have been conducted in neuroscience in order to understand free will. A complete model has not been developed. There are still a lot of contentious issues. One of which is free will may be an illusion. It has been proposed by one scientist that prior intention and deliberation are functions of the medial prefrontal cortex.
So far science has been able to explain the mind, the conscience and the emotions without the need for the supernatural concept of soul. A physical explanation of the will should be developed in the near future. The brain structure which most closely resembles the soul is the prefrontal cortex.
The Soul and the law:
Since most of our soul-like qualities can be explained materially, the existence of a soul is a matter of faith. To base abortion laws on a religious concept, such as a soul violates the establishment clause of the US constitution.
What feature makes us human?
Since we cannot establish the existence of the soul, much less when one would enter the body, what is it that makes us uniquely human? It is the brain structure known as the prefrontal cortex. As we saw previously, it is responsible for our sense of self, ourmoral reasoning, the inhibition of emotion and possibly will.
When do we become human?
It makes sense to me to say the “soul” enters the body when the prefrontal cortex is developed. The prefrontal cortex doesn’t just appear fully formed. It gradually develops.
Some of the most rudimentary features start to appear at 10 weeks. Other features don’t appear until between weeks 32 and 34. Somewhere between 10 weeks and 34 weeks, we could say that enough of the prefrontal cortex exists to say that the fetus has a “soul” and is human.
For me, when there is enough of a prefrontal cortex for the fetus to have a sense of self, I would say the fetus is human. I don’t know in which week that occurs, but for the rest of this answer, I will arbitrarily pick week 25 as being the point at which the fetus has developed a sense of self. This means that before week 25, abortion should remain legal because the fetus isn’t yet human.
What does this mean for abortions after week 25?
Now that we have established that that the fetus is human at week 25, I would be comfortable arguing about whether abortion should be illegal beyond that point. Now we can talk about back alley abortions, the fate of unwanted children, viability of the fetus, and all of the other considerations that come up around this issue.
The data for the US from 2003 shows that only 1.4% of abortions occur at or after 21 weeks. So if abortion were made illegal after week 25, it would only affect a small amount of the population. If exceptions were made for rape, incest and the life of the mother, etc. I would strongly consider it.
Until the prefrontal cortex has achieved a significant amount of development, the fetus has no “soul” and is not yet human. I argue that it is only after this point in fetal development that one can meaningfully talk about killing a human and consider making it illegal. If you try to make the curettage of a zygote illegal, you have lost me. There is no point in talking.
Keep in mind 25 weeks was picked arbitrarily for this answer. A neuroscientist would have to weigh in on where to draw the line.
©2016 Stephen L. Martin
©2016 Stephen L. Martin