Showing posts with label embryology. Show all posts
Showing posts with label embryology. Show all posts

7 Oct 2016

On the Question of Ensoulment

Soul entering human embryo at point of conception 
Holygraphic quantum-semantic electron microscopy imaging by pixwit.com


D. H. Lawrence wasn't a biologist, but that didn't deter him from sharing his metaphysical speculations on human fertilization and the development of the embryo. And, being primarily a religious thinker, the vital question for him concerned ensoulment; i.e., the moment at which a newly formed human being is animated by the Holy Spirit.
 
For Lawrence, as for the Pope, just as coition is the essential clue to sex, conception is the crucial act here: the instant that the father-quick fuses with the mother-germ is when a new unit of individuality is born, nine months prior to the birth of the actual baby.

However, we might note that - unlike the Pope - Lawrence also believes in a form of reincarnation via which the souls of the dead re-enter and pervade the souls of the living, breeding thoughts and feelings and ensuring that each person is composed of a multiplicity of forces and so isn't absolutely unique or entirely self-contained.

As interesting as the latter belief is, it's the former notion of ensoulment that I wish to discuss here, examining the view that it occurs at conception and not, for example, at the formation of the nervous system, or when there is measurable brain activity; nor when a tiny heartbeat can be heard, or fetal viability is attained; nor when the newborn is rudely slapped on the bottom and draws its first breath.

It's a view, however, that isn't shared universally. Aristotle, for example, subscribed to a model of epigenesis and believed that ensoulment - in a human sense - only occurred forty days after conception in the case of the male embryo and ninety days after conception in the case of the female fetus, when movement is experienced within the womb. Before this time he held that an embryo had the soul of a vegetable, followed by that of an animal and so couldn't be regarded as a fully human individual.     

Aristotle's views on this question influenced many of the great Christian thinkers, including Thomas Aquinas, who, even whilst conceding that the early embryo did not contain a human soul (one capable of rationality and distinguishing between good and evil), still maintained that aborting it constituted a grave sin (a position which, rightly or wrongly, the Catholic Church has been remarkably consistent on over the years).

It's worth recalling, however, that the ancient Greeks and early Christians knew nothing of fertilization; it wasn't until 1876 that Oscar Hertwig conclusively demonstrated that it involved fusion of two parental gametes and resulted in a genetically distinct zygote. Aristotle believed that the embryo arose exclusively from semen and that the female body merely provided a safe space for the embryo to develop.

Compared to this view, the notion of ensoulment at conception doesn't seem so outlandish; provided of course that one is willing to accept the idea of a non-corporeal and immortal essence animating the human being like some kind of divine breath or spark. Personally, I'm not.

I tend, rather, to share Foucault's more negative, more material view of the soul; as a virtual and historical reality that is produced as an effect of power continually shaping and disciplining the body and which ultimately serves to imprison the flesh. And, like Wilde, I hope that if ever I am to live again it can be as a little flower - no soul, but perfectly beautiful

5 Oct 2016

D. H. Lawrence and the Question of Spermism



Although D. H. Lawrence wasn't a biologist in any conventional or objective sense of the term, that didn't stop him from sharing his often peculiar ideas on human reproduction and the development of the embryo. In Fantasia of the Unconscious, for example, whilst confessing his ignorance of the sex cells in terms of chemical composition and function, he's perfectly happy to describe how the parental gametes sparkle with potency and send forth dark currents of vital energy attracting one another.

But if he acknowledges the importance of the large and mysterious mother-germ, one gets the impression that it's the father-spark that really excites his interest and he is at heart something of a spermist. For it's the much smaller sperm cell, writes Lawrence, that is most vivid and even more intrinsic to procreation. So whilst we should readily admit our indebtedness to our mother and her ovum, we should not deny the father-quick of ourselves, which is maybe the most essential element.   
   
Of course, this is not to suggest that Lawrence fully subscribed to the now obsolete and ludicrous-seeming notion that the head of each sperm cell contains a tiny human being - a theory of preformationism, widely accepted in the late seventeenth century after sperm (or seminal animalcules) were first identified under the microscope c.1677.

Although never as dominant an idea as the opposing (and earlier) model of ovist preformationism, spermism nevertheless had some influential supporters, including the German philosopher Leibniz, whose writings on the subject helped shape the development of embryology long into the eighteenth century.

There were major concerns with the spermist theory, however, not the least of which was the fact that it implied a colossal waste of human life on the part of a supposedly loving God: there are around 100 million sperm in each millilitre of semen and a healthy male adult will normally ejaculate between two and five ml. Conception, of course, only requires a single sperm cell. Attempts to get around this problem - arguing, for example, that sperm cells which failed to penetrate the ovum evaporated into the air and floated around until such time they could be recycled - failed to convince most critics.             

Later spermists abandoned this idea of panspermism, and argued instead that the homunculus present in sperm, although perfectly formed physically, had no soul; this would enter either at, or soon after, conception. If this rather neatly solved the moral issue, it unfortunately invoked the competing theory of epigenesis by making both sperm and egg necessary for the development of full human life.  

Ultimately, spermism was abandoned by the scientific community, not least of all because no one ever managed to find a little person existing ready-made in a sperm cell. But it nevertheless forms an interesting and amusing episode in the history of embryology - one that writers such as Lawrence still seem to be drawn to many years after its debunking.      


See: 

Cera R. Lawrence, 'Spermism', entry in the Embryo Project Encyclopedia (Arizona State University, 2008): click here

D. H. Lawrence, Fantasia of the Unconscious, ed. Bruce Steele, (Cambridge University Press, 2004). 


4 Oct 2016

On Embryology, Ensoulment and Stem Cell Research



By his own admission, D. H. Lawrence wasn't an objective scientist or a scholar of any kind; neither an archaeologist, nor an anthropologist. Nor was he an embryologist, but that didn't deter him from sharing his thoughts on human fertilization and the development of the embryo and fetus. 

In Fantasia of the Unconscious, for example, whilst not knowing anything about sex cells, he's happy to assert that the parental gametes continue to exist - sparkling and potent - within the zygote, forever sending forth vibrations and dark currents of vital energy. In other words, although Lawrence accepts that the sperm and ovum fuse at the moment of conception, he believes that the original parent nuclei somehow survive within the new diploid cell and function as well-heads of vivid life.

I'm not sure that's the case and, indeed, even for Lawrence this is only a preliminary rather than an intrinsic truth: this, the intrinsic truth - the truth that really matters to him, as to many religiously-minded people - is that emanating from the fusion of the father-quick and mother-germ is a new unit of unique individuality. Lawrence thus shares the papal belief that conception is the crucial  moment at which the Holy Spirit enters and a new human soul is born, nine months prior to the birth of the actual baby.

Such a mystical line of thinking wouldn't really matter or particularly concern me, if it didn't have an effect on public policy and often inhibit scientific and medical research - such as embryonic stem cell research, for example. The problem with this research, from a religious perspective, is clearly a moral one: it entails the destruction of human embryos and the souls they embody and is therefore a form of murder.

In order to demonstrate how unreasonable such a view is, we need to remind ourselves just what stem cell research actually involves and what potential benefits it offers ...

First of all, it's important to remember that the embryos used will have been cultured in vitro and are not harvested directly from a woman's body. Secondly, we should recall that they are at an incredibly early stage of development, just a few days old, and consisting of no more than around 150 cells; we're talking blastocysts not babies here.

A small group of the cells inside the microscopic blastocyst are embryonic stem cells and these have two properties that make them of such great interest to scientists: (i) they can remain in an unspecialized state for long periods of time and (ii) they are pluripotent - which means they have the potential to become any specialized cell in the human body.

Clearly such cells have much to teach us about cell division and cell differentiation, which, as Sam Harris points out, would "almost certainly shed new light on those medical conditions, like cancer and birth defects, that seem to be merely a matter of these processes gone awry". Harris also powerfully addresses the issue of embryonic termination. There is not the slightest reason to think that embryos at the 150-cell stage "have the capacity to sense pain, to suffer, or to experience the loss of life in any way at all".

On the other hand:

"What is indisputable is that there are millions of human beings who do have these capacities and who currently suffer from traumatic injuries to the brain and spinal cord. Millions more suffer from Parkinson's and Alzheimer's diseases. Millions more suffer from stroke and heart disease, from burns, from diabetes, from rheumatoid arthritis, from Purkinje cell degeneration, from Duchenne muscular dystrophy, and from vision and hearing loss. We know that embryonic stem cells promise to be a renewable source of tissues and organs that might alleviate such suffering in the not too distant future."

But, thanks to the faithful - and to writers like Lawrence who share their superstitions and seemingly endorse their pro-life views - biologists and doctors are dragged before ethics committees and forced to justify their work and explain why a fertilized egg shouldn't in fact be accorded all the rights and protections of a fully developed child.

Again, to quote from Sam Harris if I may and to conclude in full agreement with him:

"Of course, the point at which we fully acquire our humanity, and our capacity to suffer, remains an open question. But anyone who would dogmatically insist that these traits must arise coincident with the moment of conception, has nothing to contribute, apart from his ignorance, to this debate. Those opposed to therapeutic stem cell research on religious grounds constitute the biological and ethical equivalent of a flat-earth society." 

 
See: 

Sam Harris, The End of Faith, (The Free Press, 2006), pp. 166-67. 

D. H. Lawrence, Fantasia of the Unconscious, ed. Bruce Steele, (Cambridge University Press, 2004).