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On persons, human life and embryos:

Part two

by Simon Longstaff

This is the second of two articles by Simon Longstaff relating to the parliamentary debate about whether or not human embryos should be destroyed to derive stem cells. The first, published in the spring edition of Living Ethics, asked: when does a person begin? Here Simon addresses three further questions about the origins of human life.

When does a human life begin?

The first thing to note about this question is that it seeks to identify the point at which an individual human life can be said to commence. From a scientific perspective, establishing the point of origin for ‘human life’ (the general category of life that is human) is a much trickier task to accomplish. This is because scientific accounts, especially that of evolution, describe human life as having emerged over an extended period of time. Although human life appears to be distinct and different to other forms of life, to the molecular biologist life appears to be remarkably similar – with human life being simply one point on a continuum. Of course, those who explain the origin of human life in mythical or religious terms often identify a particular moment when human life, distinct from all other types of life, was created. Much turns on the relative status of these different accounts of the origins of human life.

Although the debate about embryonic stem cells is influenced by speculation about when and how human life begins, the more immediate question to be considered here is to do with when a particular human life can be said to commence. Although some cultures still believe that human life is initiated by a spiritual intervention unrelated to biological processes, there is overwhelming scientific evidence that each individual human life begins with the first division of a human egg cell. From that point onwards, an embryo is formed. However, the formation of an embryo does not necessarily mean that such a life is inherently viable. Some embryos possess internal ‘weaknesses’ (eg. poorly functioning mitochondria) that restrict their capacity for life.

Whether the life of an embryo continues or not depends on a large number of factors. For example, in nature, at least a third (and some say as many as two thirds) of all embryos perish because they have not implanted in a womb – a fundamental precondition for healthy development. If all goes well, a healthy embryo may have the capacity to develop into a foetus. With further good luck and appropriate care a child may eventually be born and grow into an adult human being.

How does a human life begin?

Apart from cases of miraculous conception, whether fertilised in utero or in vitro the trigger for human life has been, until recently, the introduction of a male’s sperm into a female’s egg. The introduction of the sperm initiates a process by which the egg then begins the process of division – syngamy – normally incorporating and combining genetic material from both the egg and sperm. For the majority of human history fertilisation of an egg has occurred through the mechanism of sexual intercourse. More recently, advances in reproductive technology have allowed us to initiate human life by inserting sperm directly into an egg in vitro – that is, outside the human body. The fertilised egg is then allowed to develop for a period of time before being implanted in a womb – after which the normal process of growth and development continues in utero. It has also become possible to cause the egg cells of human beings to begin dividing without first being fertilised by a sperm cell. The process, parthenogenesis, occurs naturally in many plant and insect species. It can be induced in mammalian egg cells using either an electrical or chemical stimulus. Where parthenogenesis is employed and human life begins, the subsequent embryo possesses only the genetic material contained in the nucleus of the egg prior to stimulation.

What is a person?

In philosophy, the term ‘person’ refers to a being that is capable of bearing the full range of moral rights and responsibilities – including, for example, rights to life, liberty, privacy etc.. In the law, the concept of a ‘person’ has been extended to include the fictional ‘personhood’ of entities like the corporation – a device contrived to allow a ‘non-natural’ (imagined) entity to hold some (but not all) of the rights and responsibilities of natural persons. Thus, the law distinguishes between ‘natural’ and ‘non-natural’ persons. For the sake of this discussion, it is only necessary to consider ‘natural’ persons – persons that are real rather than fictional. Yet, in either case the salient point is that it is only ‘persons’ who can claim moral rights or be expected to discharge equivalent responsibilities.

Understood in these terms, the decision about who or what is a ‘person’ cannot be decided as a matter of simple fact. Rather, an essential exercise of judgement is required. Traditionally, it has been held that only human beings can be considered persons. This is because the concept of personhood has always been linked either to theological or psychological attributes said to be possessed, exclusively, by human beings. In the former case, theologians (at least Jewish, Christian and Muslim theologians) have accorded personhood to human beings because of their perceived status as having been made ‘in the image of God’. In the original Hebrew texts it was understood that man had been made in the ‘moral image’ of God – a distinction marked by humanity’s capacity to reflect, to understand the nature of ‘good’ and ‘evil’ and to make ethical choices.

Even without theological assumptions being held, similar capacities have been identified by philosophers as the underlying characteristics required for the ascription of personhood. For example, the capacity for self-awareness and conscious reflection are commonly cited as the distinguishing features of personhood. The British philosopher John Locke probably captures the dominant thought about ‘persons’ as well as any other when he wrote that a person is:

... a thinking intelligent Being, that has reason and reflection, and can consider itself as itself, the same thinking thing in different times and places; which it does only by that consciousness, which is inseparable from thinking, and as it seems to me essential to it.(1)

As will be seen, this kind of discussion of ‘persons’ implies the existence of a ‘ladder of being’ with persons on the top rung. This is not to say that other forms of being are unimportant or that they can be treated with careless disregard for their welfare. However, there is a real sense in which an ethical line is drawn in the sand and that the greatest ‘wrongs’ are those that violate the rights of persons. This is one reason why so much intellectual effort has been devoted to the task of establishing criteria for who/what is a person and who/what is not.

Some philosophers, like Peter Singer, have argued that not all persons are human beings and perhaps more controversially, that not all human beings are persons. He argues that some animals possess all of the characteristics required for the ascription of personhood (in particular the capacity to form and hold preferences). He also points out that some human beings (including newborn babies and those suffering profound forms of intellectual impairment) cannot satisfy the criteria of personhood – at least not on an individual basis.

Others argue that the dignity of personhood should not be conferred on an individual basis at all. Rather, the judgement should be made on a collective basis by assessing certain ‘classes of being’ as exemplified in their most excellent form. On this argument, one would distinguish, say, chimps from humans on the basis that Mozart is obviously a ‘person’ in the way that the most advanced chimp is not. To think in these terms is to invoke the older idea of a ‘species being’ – enjoying its own history and dignity – which all of its members share irrespective of their personal attributes. Of course, the objection to this approach is that the odds are always going to be stacked in favour of humanity as humans establish themselves as the measure against which all other forms of being must be assessed. This is not a debate that can be settled here. The important point is that the central ethical question is, “what is a person?” Human life only takes on peak, ethical significance if and when it gives rise to persons.

A prior discussion of this topic appeared in the previous issue of Living Ethics.

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