What does it mean to be a person? Is it possible to be a human being but not a person? What duties do we owe to persons as opposed to non-persons? These sound like the abstruse musings of philosophers light years away from the practical issues of modern medicine. But in fact disagreements about personhood lie at the heart of many current bioethical debates, including those involving stem cell manipulation, prenatal screening, medical infanticide, the persistent vegetative state, dementia and psychiatric illness.

Modern approaches

For centuries it was generally accepted that the terms 'person' and 'living human being' were virtually equivalent. But over the last two decades, a number of influential modern philosophers, including Peter Singer, Jonathan Glover and John Harris, have challenged traditional understandings of personhood. As we will see, this has led them to some startling conclusions.

For Peter Singer a person is a being who has a capacity for enjoyable experiences, for interacting with others and for having preferences about continued life. For John Harris a person is any being who is capable of valuing their own life.

Once this kind of definition is accepted, there are a number of logical implications. Firstly it is immediately obvious that in order to be regarded as a person, you must have an advanced level of brain function. In fact you must have a completely developed and normally functioning cerebral cortex. Secondly, there must be a significant group of human beings who are non-persons. These include fetuses, newborn babies and infants who lack self awareness, and a large group of children and adults with congenital brain abnormalities, severe brain injury, dementia and major psychiatric illnesses.

Thirdly, there are many non-human beings on the planet who meet the criteria of persons. These include at least chimpanzees, gorillas, monkeys and dolphins, but may also include dogs, pigs and many other mammals. In fact it has even been argued that within the foreseeable future some supercomputers may meet the criteria to be regarded as persons.

Speciesism and fragility

Those who meet the criteria of persons have moral rights and privileges. They deserve to be protected from those who would injure or kill them. They should be allowed to exercise their own choices or autonomy as much as possible. But the same rights and privileges do not extend to non-persons. Peter Singer puts it like this, 'only a person can want to go on living, or have plans for the future, because only a person can understand the possibility of a future existence for herself or himself. This means that to end the lives of people against their will is different from ending the lives of beings who are not people…killing a person against his or her will is a much more serious wrong than killing a being who is not a person.'(1) In other words killing a chimpanzee is a much greater moral evil than killing a newborn baby or an adult with Alzheimer's disease.

When people respond with incredulity, Singer argues that to make moral distinctions on the basis of species is to be guilty of a new crime, 'speciesism'. Instead we should make moral distinctions on the basis of 'ethically relevant characteristics', such as the ability to choose and value your own life.

Of course there are major logical problems with this kind of definition of personhood. In effect Singer has replaced one form of discrimination with another. Instead of discriminating on the basis of species, he is now arguing that we should discriminate on the grounds of cortical function. In fact if we are into name-calling we could call him a 'corticalist'. But why should corticalism be preferable to speciesism? Of course Singer may wish to argue that cortical functioning is 'ethically relevant' whereas species membership is not. But this is an arbitrary distinction that is hard to defend on entirely logical grounds. Why should the functioning of a 5mm layer of neurones be the central and only moral discriminating feature between beings? On purely logical grounds species membership is a more coherent and fundamental basis for making ethical distinctions between beings.

Personhood as defined above is a remarkably fragile and contingent property. At the moment as you read this article you can be regarded as a person. But if, when you walk out of your door, a brick falls on your head leading to cortical damage, you are no longer a person. Of course if, following rehabilitation, your cortical function recovers, then you will become a person again. Can something so fundamental as personhood be so fragile? On Singer's definition it is not at all clear if a human being who is anaesthetised, comatose, intoxicated, delirious, psychotically confused or merely asleep remains a person. If a burglar came into your room at night and killed you painlessly in your sleep, would they have committed a crime? Singer and colleagues answer this challenge by arguing that personhood is only lost if consciousness is permanently lost, but why on logical grounds should this be so? Suppose I suffer severe brain injury but have the prospect of gradual recovery to normal consciousness over the next ten years. Am I a person in the intervening period? If someone kills me in my unconscious state are they guilty of the serious crime of killing a person or the less serious crime of killing a non-person?

A Christian perspective

At the heart of this secular philosophical perspective is the idea that you earn the right to be called a person by what you can do, by demonstrating that your brain is functioning adequately, by thinking and choosing. So how do we respond as Christians? What does it mean to be a person in the light of the Christian revelation? As we shall see, in the history of philosophy, the very idea of a person comes directly out of a Christian understanding of what it means to be a human being. It is necessary to look briefly at some rather abstract theological history, but I hope it will become plain how it is relevant to the modern debate.

God is personal

The original Greek word for person (prosopon) means literally 'the face', but in ancient Greek it also referred to the mask that actors used to represent the character they were playing in the theatre. In Greek and Roman thinking what mattered about an individual was the face they showed to the world, the role they played in society. We have retained this meaning when we refer to someone's 'persona'. It is the public face they show to the world. It is interesting that this is how the word is used in the Greek New Testament. At several points God is described as one who shows no favouritism. The literal Greek says that he is not a respecter of persons, meaning that he is not influenced by our external and social role.(2)

However in Hebrews 1:3 the Son is described as the exact representation of God's person and a different word is used, hypostasis, which literally means 'what lies under'. The early church fathers, as they reflected on the nature of the Godhead and the meaning of the Trinity, fastened on this word hypostasis to describe the three persons of the Trinity. God's ultimate being (what 'lay under' his activity), was in the form of persons - persons giving themselves to one another in love. And as human beings are made in God's image, we too are created as persons. We reflect God's nature in our personhood; we are created to give ourselves to God and to others in love.

Relationship is vital

Just as the three persons of the Trinity are individually unique, yet give themselves continually in love, so each human person is unique, yet made for relationship with others. Personhood is not something we can have in isolation - in Christian thinking it is a relational concept. Descartes came up with the famous statement, 'I think, therefore I am'. It's a definition that led ultimately to the modern concepts of Singer and Harris. By contrast we might suggest an alternative Christian version, 'You love me, therefore I am'. My being comes not from my rational abilities but from the fact that I am known and loved - first of all by God himself, and secondly by other human beings. This is why the experience of rejection and isolation can be so psychologically devastating, and why children who have never experienced love and acceptance fail to develop into normal healthy adults. But even if I am rejected by other humans, I am still a person. Ultimately my personhood rests on the fact that God called me into existence and that he continues to know and love me.(3)

The idea of a person as hypostasis, derived from the Christian theology of the Trinity, gradually entered Western philosophy and remained of central importance up to the present century. Humanism took on essentially the same understanding of the human person, although its theological basis was conveniently forgotten. It is only recently that the basic concept has been derided and challenged by a number of philosophers, including Singer and colleagues.

Doing or being?

For Peter Singer my personhood depends on what I can do, on the functioning of my cerebral cortex. But in Christian thinking my personhood rests on who I am, on the fact that God has called me into existence, and continues to know and love me. Human beings do not need to earn the right to be treated as godlike beings. Our dignity is intrinsic, in the stuff of our being, in the way God has made us and the way he knows and loves us.

This Christian understanding of personhood is much more permanent, more resilient, than the secular one. As we saw, to Peter Singer your personhood might disappear at any moment if your cortex starts to malfunction. But in Christian thinking, whatever happens to you in the future, whatever disease or accident may befall your central nervous system, even if you are struck down by dementia or enter a persistent vegetative state, you will still be you: a unique and wonderful person known and loved by God. It is God's love that preserves our identity throughout the whole of our lifetime - whatever tragic and unexpected events may befall us - and on into eternity. And even when we were in our mother's womb, God was loving us and calling us into existence. As the theologian Gilbert Meilander put it, 'He was with us in the womb, as he will be with us in the tomb'.(4)

Practical implications

So what are the practical implications for medical ethics of this rather abstract theology? It's a huge topic and I can only point out a few headlines. Firstly, in Christian thinking my moral value and significance does not depend on the vagaries of my CNS function, but on my creation in God's image. Human beings are godlike beings. We are lovingly designed by our Creator to reflect his character and nature. Only human beings, in all the vast array of life on planet Earth, have this privilege and responsibility. Hence we are to treat all human beings, however tragically incapacitated, with wonder, reverence and respect. We are called to protect all human beings from abuse, from manipulation and from any who would deliberately end their life. We cannot rate some lives as more worthwhile, more valuable than others. The malformed baby, the Alzheimer's sufferer, the unwanted fetus, and the person with terminal motor neurone disease; all have lives of unique significance and value, all are known and loved by God. This does not mean that we have an absolute duty to provide every possible treatment, or to continue life-supporting treatment in every case. Sometimes it is right to withhold or withdraw medical treatment that is burdensome and can bring no lasting benefit. But this is not because we estimate one life as less valuable or less morally significant than another. Each human being deserves our wonder, respect and compassionate care.

Secondly, whereas the law does not recognise personhood until the moment of birth, Christian thinking points to the moral significance of the unborn fetus. As illustrated so powerfully in Psalm 139, God is involved with us even in the intrauterine environment. And although we cannot ultimately know in what sense God has a relationship with an embryo (and thoughtful Christians continue to differ on this issue),(5) it seems to me that we must treat even a microscopic human embryo as a unique and precious being whom God is calling into existence. And if this is right then we cannot destroy one human life to provide embryonic stem cells for the benefit of another human life.

Thirdly, as far as we know, of all the species on the planet only Homo sapiens is made in God's image and hence only human beings can be called persons. Although we are called to treat not only chimpanzees and dolphins but all sentient beings with care, as befits beings made by God, we cannot value their lives as equal to those of humans. As Christians we must plead guilty to the charge of speciesism, because our God is speciesist!

Finally, as we saw, there is no such thing as an isolated human person, and therefore we cannot take ethical decisions as though human beings are isolated entities. In Christian thinking we are all bound together in bonds of duty and care. We are meant to be a burden to one another. In fact our lives are meant to be ones of 'mutual burdensomeness'! We come into the world totally dependent on the love and care of others, we go through a stage of life when we care for others, and most of us will end our lives totally dependent on the love and care of others. This is part of what it means to be a person. So even if a patient with a terminal illness feels that their own life is worthless and requests the right to be killed, we cannot agree. The intentional killing of one person damages all of us, because we are all locked together in community. And by contrast when we show compassion and love for the weakest and most pathetic members of our society, we are expressing an essential element of our humanity. This is the way we demonstrate God's image. This is the way he has made us to be.

Conclusion

What does it mean to be a person? As I've tried to demonstrate it's not just a question of academic philosophy. As Christian medics we are called to demonstrate the reality of what we believe. It is by our behaviour, by our compassionate caring, by our sensitivity and respect for the dignity of every patient, the helpless, the confused, the malformed, the unborn and the disabled, that we can really provide the answer.

References

• Singer P. Rethinking Life and Death. Oxford: OUP, 1995:198
• Rom 2:11; Eph 6:9; Col 3:25
• Ps 139; Jer 1:5
• Meilander G. Bioethics: A Primer for Christians. Carlisle: Paternoster Press, 1997:30
• See for example, Berry C. Beginnings: Christian Views of the Early Embryo. London: CMF, 1993; Saunders P. Deadly Questions on the Status of the Embryo. Nucleus 1998; July:28-34; Berry C,Saunders P. Head to Head - Prenatal Screening. Nucleus 1999; April:36,37

Further reading

• Wyatt J. Matters of Life and Death. Leicester: IVP, 1998
• McFarlane G, Moore P. What is a Person? CMF Files no 10. London: CMF, 2000
• Zizoulas J. Being as Communion. New York: St Vladimir's Seminary Press, 1991