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Galileo and the human embryo

There is good reason for some disquiet about the Church’s attitude towards the scientific underpinnings of certain moral issues. As the Galileo affair should have taught us, scientific matters have to be settled in a scientific way and not by reference to theological or dogmatic positions.    Part 2.

by Max Charlesworth

The traditional Catholic view on the moral status of the human embryo distinguished between the embryo up to about 40 days into its development, and the later stages, after 40 days, when it was deemed to be ‘formed’ or ‘animated’ by an intellectual soul i.e. when it had the beginnings of a nervous system and brain. Before 40 days it was held to be a sin, but not the sin of homicide or murder, to abort the embryo. St Augustine (384-430) argued that if the embryo was ‘not yet formed, and therefore not yet endowed with its senses’, there cannot be ‘a living soul in that body’. (see the study by the Anglican theologian G.R. Dunstan, ‘The Human Embryo in the Western Moral Tradition’, in The Status of the Embryo: Perspectives from Moral Tradition, Oxford University Press, 1988.). Medieval philosopher-theologians, such as Albertus Magnus and Thomas Aquinas, also maintained the same view, as did Islamic Aristotelians such as Ibn Sina (Avicenna) (980-1037).

This tradition of thought attempted to adjust the degree of respect and protection given to the embryo to its stage of development, but it was abruptly changed by Pope Pius 1X in 1869 who decreed that a human embryo was a human person right from the moment of conception and must be given ‘absolute protection’. Pio Nono’s teaching was completely contrary to the Catholic tradition that had prevailed for more than 1500 years. As the Anglican theologian, Gordon Dunstan, has put it : ‘The claim to absolute protection “from the beginning” is a novelty in the Christian, and specifically Roman Catholic, moral tradition. It is virtually a creation of the later nineteenth century, a little over a century ago, and that is a novelty as traditions go.’(‘The Human Embryo…’ p.40.)

In the Aristotelian tradition the human soul, or hominising principle, can come into existence only if there is there is a suitable bodily or material substratum of some complexity for the ‘soul’ to inform and this happens, so it was held, at about 40 days into the development of the embryo. As Ibn Sina put it: ‘A soul comes into existence whenever a body suitable for it comes into existence’. (cited by Dunstan, p.55.)

It is sometimes said that God ‘infuses’ a soul into the embryo, but this is a very crude way of putting things, since the emergence of distinctively human life cannot be a miraculous event brought about by God suspending the operation of the laws of nature, given that hominisation occurs in a law-like way after 40 days. Again, talk about the ‘infusion’ of the soul implies that the human soul can exist independently of the body and can be inserted into the human body at any stage of its development.  But that dualistic view of the human body and soul is philosophically incoherent. As the French theologian, Joseph Donceel, said 30 years ago: ‘ We cannot admit that the fertilised ovum, the morula, the blastocyst, the early embryo, is animated by an intellectual soul… Even God cannot put a human soul into a rock, a plant, or a lower animal, any more than he can make the contours of a circle square’. ( J. Donceel, ‘Immediate Animation; Delayed Hominisation’, Theological Studies, 37,1976, pp.127-128.)

From this perspective, it is clear that scientific facts about the development of the human embryo are very relevant to determining when the embryo becomes a human person. First, the idea that the human person begins at the moment of conception means that an intellectual soul could be infused into two or four celled organism even before the nervous system and the human brain had begun. Again, there are other embryological facts that have to be taken into account. Thus, an eminent English embryologist, Anne McLaren, has criticised those who use the term ‘embryo’ to describe all the phases or stages of embryonic development and has shown how different those stages are: ‘The first two weeks after fertilisation are essentially a period of preparation for the later development of the embryo. The fertilised egg divides once or twice for the first few days to form a clump of cells which then spends about the next week burrowing into the wall of the woman’s uterus. During this period of implantation, most of the cells become progressively committed to various tasks concerned with the protection and nourishment of the future embryo. Eventually, they or their descendants form the placenta and the various other tissues that surround the embryo. At the end of implantation, there remain some cells not involved in any of these life-support systems. It is in this group of cells (the “embryonic plate”) that the so-called primitive streak appears, marking the place where the embryo finally begins to develop’. (7) (7. Anne McLaren, ‘Why study early human development?,  New Scientist, 24 April, 1986, p.4. See also Elisabeth Finkel, Stem Cells, Melbourne, ABC Books, 2005, pp. 26-27.)

It seems then that we cannot speak of the embryo proper until after something like the 14th day of development, and that the view that embryonic life begins at the moment of conception, when the male sperm joins with the female ovum, cannot be sustained. Many of those who oppose embryonic experimentation for research on stem cells speak of the early embryo as a ‘unborn child’, but this is clearly an abuse of words since there is no ‘child’ in existence until the 14th day. Others have argued that the early embryo is a ‘potential’ human being since it will eventually become a human, but this neglects the fact that the development of the embryo is contingent upon it being successfully implanted, a risky process since it has been estimated that a relatively high proportion of embryos are spontaneously aborted.  A 1998 survey, for instance, suggests that almost 50 per cent of naturally conceived embryos are lost by the time that pregnancy is recognisable. (8) (8. See Norman Ford, The Prenatal person: ethics from conception to birth, Oxford, Blackwell Publishing, 2002, p 77).

Embryonic development also depends upon on the embryo interacting with its mother’s body, since the mother is not simply an inert ‘container’. Again development depends on external factors such as the mother’s health, including risks from radiation and drugs and malnutrition and so on.  It would, in fact, be better to speak of the early human embryo not as a potential human being, but  as a ‘probable’ human being which may, if all goes well with a large number of contingent factors, develop into a real human being. It is certainly not the case that the early embryo will inevitably develop into a human being. The statement that is often made, ’the embryo would never become human if it were not human already’, simply glosses over all these facts about embryonic development.

Finally, some Catholic theologians have argued that, although we don’t know with certainty that a human person begins at the moment of conception, it is ‘safer’ to hold that it does begin at that time given that there is a possibility that the embryo may be a human being. But, for this argument to work, we need to know that there is a real possibility, or a reasonable degree of probability, of the early embryo being human and, as we have seen, there is in fact a overwhelmingly strong probability of it not being a human person.

There is, of course, a great deal more that we do not know about the process of embryonic development, and one hopes that scientists will continue their investigations so that the process will become safer and more subject to our control. It would help them, and us all, if they were not hindered by the simplistic religious views  of some, like Galileo’s judges, who refuse to look at the relevant scientific facts.

Part 1 of this article, published last week, can be accessed by clicking here

Max Charlesworth is a former Professor of Philosophy and has written a number of books on the philosophy of science, including 'Life Among the Scientists' (Oxford University Press, 1989), 'Life, Death, Genes and Ethics', ABC Boyer Lectures (ABC Books, 1989), and 'Science, Non-Science and Pseudo-Science', (Deakin University Press, 1980).




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