This is another archival repost from the old blog — this one from january 2008.
This post is part six in a series. The series so far can be found here.
Cogito, ergo sum.
René Descartes, 1637.
I’ve given five posts and several thousand words over to introductions to principles in development, evolution and molecular biology. I won’t be dropping those topics altogether, but it’s time to explore new territories in the Sunday syndrome, including the philosophical and political. Things should be a little more digestible from here on. Chromosomal aberrations — that is, large scale mutations in which so much genetic material is deleted or duplicated that a difference is visible under the light microscope — have serious effects on development. We have discussed a few examples of syndromes which arise in individuals which carry these aberrations, but the individuals we see are the exceptions. In each case, I have given the frequency of the disease in terms of live births, but the frequencies are much higher in conceptions. The deletions that we see in live births are a relatively small proportion of the genome, and we rarely see live births in which both of the two copies of the genome are affected. More extreme deletions do occur, but the individuals carrying them never make it to birth. The rule is miscarriage.
Perhaps the most extreme syndrome that we see surviving to term is anencephaly. And yet, paradoxically, anencephaly has the smallest number of symptoms and directly affected organs of any of the syndromes that I have so far discussed. In most cases, physical development is largely normal, with the exception of one particular system: the nervous system. Anencephaly is classified as a neural tube defect, alongside spina bifida, and is caused by an error during the developmental process of neurulation.
Neurulation starts on day 18 of development, and is complete by day 30. The cells along the centre of the back fold in to form a grove, which then closes over to form the neural tube, the precursor of the central nervous system. With a frequency above one in every 500 births, closure of the neutral tube fails to complete. If this occurs towards the posterior,spina bifida arises, and the individual is physically disabled. When this occurs at the head, the skull does not form properly, and the amniotic fluid destroys the developing brain. Those individuals which survive to term are born without a brain. All will die within hours of birth. The reason anencephaly is the most extreme of our syndromes is because it affects those parts of us that are most uniquely human, and raises important questions about medical ethics, and the fuzzy boundaries of humanity.
This is one of the great social functions of science: to free people from superstition.
Last year, a court case was brought in Ireland to determine whether a woman whose foetus had been diagnosed with anencephaly could travel to the UK for abortion. A French website exists solely to oppose the abortion of anencephalics . It is murder. Despite the fact that these individuals will never have a life. Never have a thought or feeling, either of pain or joy. Never know that they exist or will cease to exist. Never, no matter what the anti-abortionists may tell you, “know God”. There is no they.
I am not willing to believe that the anti-abortion movement is solely about the control of women — though that is undoubtedly a motivation for cynically manipulative church elders. Rather, it is about simple rules. When faced with difficult moral decisions some people are just too cowardly to give important decisions the time and thought that they deserve, and would rather follow an easy formula. Why take the time to make an informed and reasoned decision on an important issue, when you can have somebody else make an uninformed one for you? Why waste paper on a law library when there’s a handy single volume that never needs revising? Why test competing ideas when yours comes straight from the Lord? Why examine his world when his world is so stubbornly rebellious? Sweep aside the complicating details that five hundred years of discovery have burdened us with, and go for the simple answer.
Physiology, psychology and neuroscience, with a little help from physics and philosophy, have destroyed simple dualism. Developmental biology has destroyed the simple boundaries of life and consciousness. Evolutionary biology has destroyed the simple boundary between species. Biochemistry has destroyed the simple boundary between life and non-life. Astronomy has put us in our place and physics has overturned our understanding of that place. It’s time to stop pretending that there are simple rules.