What is A Person?

by Graham McFarlane & Pete Moore

Understanding what it is to be an individual human being is vital if we are going to be able to make informed ethical decisions, particularly those that surround the start and end of life. Not surprisingly, it is an area strewn with controversy.
By presenting a range of currently expressed views and ideas, this paper intends to stimulate informed debate.

Who am I? It is one of life’s basic questions and it has troubled philosophers though the centuries. One aspect of the answer lies in working out what it is to be a person. This is not just academic interest. Your conclusion will affect the way you think about key issues surrounding life, death and disability.

To start with we need to consider the ways that human beings are different from other animals. After all, genetics now tells us that we share ninety-eight per cent of our genes with chimpanzees and seventy-five per cent with round-worms (nematodes). So on a genetic level we are remarkably similar, but on a moral and ethical level most people believe that we are superior.

Forming an opinion about when a person’s life starts and ends will also effect our views of technologies such as pre-implantation genetic diagnosis and antenatal screening. These look for imperfections in embryos and fetuses and give the option of terminating that organism’s life. If you do not consider that an embryo has the status of a person, then this may not worry you, however if you do believe that embryos are small persons then you will see this act as murder.

At the order end of life, our ability to maintain bodily functions in intensive care facilities also makes us ask questions of the moment of death. Is a person who has no function in the cortical areas of his or her brain alive or dead? The question needs to be answered urgently if you are going to allow major organs to be removed and transferred to a waiting patient.

In addition, an assessment of what it is to be human will help us work out whether it is ever right to take actions that have the primary intention of shortening or ending a person’s life.

Biological Development

The process of development that leads from an egg and a single sperm, to a newborn baby is remarkably complex and poorly understood.
But increased understanding of these biological processes has done little to reduce the animosity aroused in any debate that discusses the time when this developing unit of life becomes a person. The following is a review of some of the more commonly argued markers.


From the moment that a sperm and egg unite and start to act as a single entity many Christians and people of other, or no, faiths, say that we have a new human being – a new person.

Taken at its most basic, fertilisation brings about the emergence of a new combination of genes and the start of a new unit of biology. Everything that happens after this point is merely a process of development. The very fact that this being is a member of the human species gives him or her the status of a person.

Those arguing against this view say that while the detailed genetics may be unique, you don’t know whether it will spontaneously split into two and become identical twins. If the day – 1 embryo is a person, then how do we view these twins?

They also point to the number of embryos that fail to implant, estimated at between 25% and 75%, saying that it is difficult to believe that all these are lost people. In addition they point out that fertilisation is a process that occurs over at least 24 hours, so there is no defining ‘moment of fertilisation’ to look back on.


Implantation, where the embryo buries into the lining of the mother’s womb, is another suggested marker. This is the time when a maternal embryonic relationship begins to form. The embryo releases human chorionic gonadotrophin, which wards of a period and prevents itself being washed away. Thus without a successful implantation, which starts at about 5 to 6 days after fertilisation and is completed by about 14 days, its survival chances are nil.

Opponents of this time point out that implantation occurs before any nervous system is up and running. They argue that we accept that brain death is the time when a person’s life ends, so there can be no person until the brain, or at very least some nerves, hae started to function.

Up to 14 days the embryo has been a simple ball of cells. However, from this point a group of cells distinguishes itself within the ball and forms the primitive streak, the cell mass that will eventually become the full-grown baby. It was for this reason that the Warnock commission set 14 days as the point beyond which no-one is allowed to perform experiments on human embryos.

Neutral Plate

At around 17 days after egg and sperm meet the neural tube begins to form. If you see the nervous system as the key to being human,
then this is your moment. However, the first nerves are long way from forming the complex network that we accept as being a functioning brain.

In Human Form

After seven weeks of development all organs are basically in place and the embryo looks distinctly human. It is now called a fetus. Early thinkers such as Aristotle (383-322 BC) and the Catholic theologian and philosopher Thomas Aquinas (1225-1274) decided that this physical maturity signalled the time when the embryo become ‘ensouled’; became a person. According to Islamic scriptures the embryo is sacred from day-one and deserving of protection, but after about 6 weeks from fertilisation God breathes in the person’s soul.

However, biologically this stage is just part of ongoing development and many of the organs, while present, will take weeks or months before they perform fully.

Ethical Declarations

Over the years the medical profession has made a series of declarations that contain comments about its view of the nature of human life and our need to treat it with respect.

Declaration of Sydney (1968)
This addressed issues about deciding when a person is dead. The difficulty is that modern techniques have produced some situation where it is difficult to know quite when a person has died. In these situations simple measures such as a non-beating heart, or lack of respiration are not sufficient. In these cases, this declaration states that the decision should be left with a qualified clinician.

Memorandum issued by the Honorary Secretary of the Conference of Medical Royal Colleges and the Faculties in the United Kingdom (1979)
This recognised that cessation of the heart was no longer accepted as equivalent to the moment of death. It says that ‘Whatever the mode of its production, brain death represents the state at which a patient becomes truly dead, because by then all functions of the brain have permanently and irreversibly ceased. It is not difficult or illogical in any way to equate this with the concept in many religions of the departure of the spirit from the body.’

Declaration of Helsinski (revised, 1975)
This declaration addressed the issue of experimentation. It acknowledges the need to have high regard for the environment and for the welfare of animals in experiments. In particular it reminds the medical profession that, if human subjects are involved, it has a duty to put the health of the patient first.

Declaration of Oslo (1970)
This declaration paved the way for abortions to be carried out, in recognition that there will be occasions when the vital interest of the mother and developing child conflict. However it places this within a framework that recognises the Declaration of Geneva, under which a doctor states, ‘ I will maintain the utmost respect for human life from the time of conception.’


Historically a lot of weigh has been given to the first moment when a woman feels her baby move inside her womb-quickening. This occurs at about 16-18 weeks from fertilisation.

The problem with this marker is that ultrasound scans now show that the fetus has been moving for weeks before this moment. The movement hasn’t been felt because previously the fetus was not heavy enough.


Neonatal intensive care units can now keep very premature babies alive. The youngest was born after only 22 weeks of development.
If a baby can survive outside the womb, there can be no doubt that he or she must be a person, and by implication, this personhood must apply to all unborn fetuses of this age.

Opponents of this view point to the massed banks of equipment needed to maintain a very premature baby’s life, saying that this is hardly independent survival.

But others say that the equipment makes no difference because if a person needed to be fully independent, then this would only occur once they had reached their teens, or beyond.


The moment when a baby leaves the confined of the womb and starts to breathe air is the legal point at which the status of a person is conferred. Many people point out that, while this is legally convenient, the timing of the birth itself is one of the least significant developmental stages in the child’s life.

After all, a premature delivery could bring it earlier, or a delayed labour could hold it back it by days or weeks. This has little to do with the baby’s personal development.

Self Awareness

This is the point at which a human being becomes aware of itself and other persons as distinct entities.

A problem with using this marker is that clearly self awareness only occurs a few weeks or months after birth, and sometimes ends prior to death. It also leads to the situation where some higher non-human animals are placed in the same category as people.

A Conclusion?

Sincere people of all faiths differ in their understanding of the time when a person’s life starts. For a Christian it is important to understand the biology and then see how it fits in with biblical teaching and debate. It is also important to remember that, whatever the process, we are all created and loved by God.

Read more: (Part 2) ….Discussion of Personhood…

Christian Medical Fellowship (CMF) Files No. 08, 1999