The moment of quickening

Patsy McGarry has an interesting article in the Irish Times today on the surprisingly fluid nature of the Catholic Church’s stance on abortion:

… some of the church’s greatest teachers and saints believed no homicide was involved if abortion took place before the foetus was infused with a soul, known as “ensoulment”. This was believed to occur at “quickening”, when the mother detected the child move for the first time in her womb. In 1591, Pope Gregory XIV determined it at 166 days of pregnancy, almost 24 weeks.
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St Thomas Aquinas (died 1274) held “the vegetative soul, which comes first, when the embryo lives the life of a plant, is corrupted, and is succeeded by a more perfect soul, which is both nutritive and sensitive, and then the embryo lives an animal life; and when this is corrupted, it is succeeded by the rational soul introduced from without (ie by God)”.

Centuries of enlightened thinking (yes, even in the Catholic Church) understood that there were nuances of life, that human development was a process of many stages rather than an instantaneous event. He did not have access to our scientific knowledge, but nothing we have learned since has refuted Aquinas’s basic hypothesis. We now know the exact stage of embryonic development when the central nervous system forms, and have a fair idea when awareness of stimuli such as pain develops. It is no accident that Pope Gregory’s moment of quickening is similar to commonly defined abortion limits, because they both derive from the same logical considerations. The transition from “vegetative” to “animal” states of being is grounded in hard evidence, even if the line between “animal” and human consciousness continues to evade us.

It does seem strange then, that some time in the 19th century – just as scientific advances were shedding light on the moment of conception – the irrational notion of an instantaneous beginning to human existence began to take hold. One moment, there are apparently just a few cells swimming around and in the next a perfectly formed human soul appears, even though nothing much physically has changed. Perhaps it is just our instinctive aversion to ambiguity – we humans do like our tidy mental pigeonholes. Whatever the source of this gut feeling, it is difficult to muster a logical argument to back it up. If mere clusters of human cells were a human person, then HeLa would be a person, or the precipitate from your last blood test. If personhood were defined by a unique combination of DNA, then my twin nieces would not be two separate people. If it were the particular expression of that DNA, then how can you say that different organs constitute a single person? The only consistent way to define a “person” is through the presence of a mind. I think, therefore I am.

Without a mind, and by extension a brain to contain it, a person cannot exist. We already accept that braindead adults are no longer people and so can be unplugged and grieved for in peace without the law getting involved. If a living thing that no longer has a working brain is not a person, then surely a living thing that never had a working brain is not a person either?