What Does it Mean to be Human?

“What a piece of work is man, How noble in reason, how infinite in faculty, In form and moving how express and admirable, In action how like an Angel, In apprehension how like a god, The beauty of the world, The paragon of animals. And yet to me, what is this quintessence of dust? Man delights not me; no, nor Woman neither; though by your smiling you seem to say so.”

…so ponders King Hamlet, in Act II of Shakespeare’s Hamlet. Shakespeare artistically captures some of the awe and curiosity many feel when considering the human form. But what does it truly been to be “human”?

“Human” is a harder concept to define than one would perhaps initially think, and different thinkers from different fields have a starkly diverse range of firmly-held ideas. And yet almost every realm and structure of our global society presupposes some sort of established definition of “human”.

Our healthcare systems elevate human healthcare needs and ultimately human life to above those of animals and plants. Our international and national judiciary systems endow humans with immutable rights from the moment of birth. Our socio-political institutions maintain humans as the exclusive building blocks of society, with unique responsibilities towards each other.

But what does is meant to be “human”? The geneticists, psychologists, sociologists, and physicists all have differing criteria for what is “human”. But interesting, in my opinion, many of the contemporary and historical views appear significantly incomplete.


The Foremost Scientific View: Genetic Reductionism

When asked to define humanness, many scientists would instinctively look to genetics. In the past decade, technical advances have allowed us to break down and analyse the genetic make-up of humans and animals with extraordinary precision. The analysis of the human genetic profile undoubtedly hit a profound historical landmark in the early 2000s with the sequencing of the entire human genome- with every gene in the human cell being mapped physically and functionally. From the genetic reductionist perspective, to be human is to simply be genetically homo sapien– that is to bear a specific set of genes common to all other humans, and unique compared with all other life forms.

This is the view held by Evolutionary Biology Professor Richard Dawkins, who write in his book “The Selfish Gene”: “We are survival machines- robot vehicles blindly programmed to preserve the selfish molecules known as genes. This is a truth which fills me with astonishment”1

On the face of it, this notion that humanness can simply be reduced to an expression of a specific genome is satisfyingly simple and empirically robust.

However, although conclusive in the biology lab, the genetic reductionist view on humanness starts to unravel when we ascend to the holistic and societal levels. Afterall, why should one genome have higher rights or greater responsibilities than all others, if the ultimate difference is that of chemical nucleotide bases? Why should human life have more value than that of a fish, fly or flower? And if humans are nothing more than a genome and its protein products, why would our human forms merit any worth or value at all?

Furthermore, if you take genetic reductionism to its logical extreme, it would view as dismembered limb, or a foetus with anencephaly (without a brain), or a skin cell in a Petri dish all as technically “human” as they bear the homo sapien genome. These trivial examples surely demonstrate that genetic reductionism is incomplete in its assessment of what is means to be human.

Neuroscience Professor Donald MacKay, in his book “The Clockwork Image” coined the term “nothing-buttery2, to describe the view that because humans are composed of chemicals, we are nothing but chemicals. He argued that in observing that humans are composed of chemicals such as genes, too many make the unwarranted philosophical leap to  say that any system, including the human being, can be wholly be explained by the properties of its component parts. This presupposition is unhelpful in nearly every field, and especially so in the defining of humanness.

Thus although helpful, genetic reduction can only give a partial answer to the question: what does it mean to be human?


The Popular Psychological View: Higher Cognitive Functioning

If one surveys the psychological literature on the defining of humanness, one finds a wide range of views and propositions. However there also seems to be a common thread that runs through the majority of popular psychological views on humanness. Most psychologists appear to define humanness in terms of our ability or capacity to perform certain higher cognitive functions. Some link humanness to the capacity to express complex emotions such as love, jealously or amusement. Others see humanness as contained in our ability to build societal structures or manipulate our environment. Others still link humanness to self-awareness and sense of identity.

However, all of these models of humanness, that tie our humanness to our high cognitive abilities and capacities, lead to some unsettling issues. This is because linking humanness with higher cognitive function immediately leads to a hierarchical spectrum of humanness, with the most cognitively able in humankind somehow becoming “more human” than the less able. And where would that leave individuals such as the new born baby, or the patient in the persistent vegetative state, or the acutely psychotic patient who has lost touch with reality? Would these individuals be somehow deficient in their humanness as they have lower-than-average higher cognitive functioning?

And on the flip-side, it is very clear that a lot of non-human agents can possess and exhibit many of the higher cognitive functions psychologists tie to human identity. Many studies show primates exhibiting remarkably human-like cognition, and artificial intelligence is becoming increasing able to emulate human decisions and interactions.

Therefore, for me higher cognitive ability alone is too fragile and changeable to bear the weight of the definition of humanness.


The Radical Bioethical View: Hierarchical Relativism

Some thinkers have taken the higher cognitive functioning model of humanness one step further, spear-headed philosophy professor Peter Singer. In his book Rethinking Life and Death Singer puts forward the radical notion that humanness is a spectrum, not an absolute, and proposed that value as a human being varies according to physical characteristics and abilities. He summarises his argument in the simple imperative: “recognise that worth of human life varies”. He goes on “[we must] take the brave step of recognising that, at a minimum, consciousness is essential if life is to be worth having” and hence “we should treat human beings in accordance with their ethically relevant characteristics”.3 He proposes that these characteristics include physical and social abilities, conscious preference for continued life, and quality of relationships with others (e.g. relatives who will grief over an individual’s death).

Singer’s relativistic view on humanness leads him to publically argue, among other things, that infanticide is morally equivalent to abortion (and should be legal), and some intelligent animals should have greater legal rights than some unintelligent humans.

For most of his listeners, including me, Singer’s views border on the outrageous and inflammatory, and have echoes of eugenics. As a doctor, the idea of me treating patients’ lives with differing values based on the size of their cerebral cortex is absurd and contrary to the ethical foundations of medicine. And besides, who is going to have the authority to decide which characteristics are superior enough to contribute to someone’s human status?

However, in fairness to Singer, he is simply taking the libertarian view of humanness to its logical conclusion, independent of social outrage!


The Emerging Sociological View: Libertarianism

Liberty and the right to autonomous living has been one of the strongest underlying currents of Western society in the past few decades. A vast number of social movements have come from people’s passionate upholding of self-determination and self-identification as important or even ultimate rights of human beings. These values have become increasingly engrained in many people’s view on what it means to be human. This view was summarised by legal philosophy Professor Ronald Dworkin who wrote in his book “Life’s Dominion”:

“The most important feature of [Western political culture] is a belief in individual human dignity: that people have the moral right and the moral responsibility to confront the most fundamental questions about the meaning and value of their own lives for themselves”.

“At the heart of liberty is the right to defends one’s own concept of existence, of meaning, of the universe, and of the mystery of life…Freedom is the cardinal, absolute requirement of self-respect: no-one treats his life as having intrinsic objective importance unless he insists on leading that life himself, not being ushered along it by others.”4

Dworkin and others do not simply view the right to self-determination as a human right- they tie it to the very essence of what it means to be human. Radical as this may sound to some, it is actually presupposition behind many libertarian movements. For example, assisted suicide and euthanasia have been illegal for many years on the ethical grounds that human life has intrinsic and immense worth that no-one, including the individual themselves, has the right to destroy. However, in recent years, the increasingly popular societal view appears to be that autonomy trumps intrinsic value of life. Thus an autonomous person has the right to dissolve the intrinsic value of their life if they express a clear and informed wish to die.

However, this libertarian view of humanness, as dependent on self-determination, leads to problematic issues. Firstly, this model leads to a view of human identity that fluctuates with consciousness. As my view of self changes over time, would it affect by objective humanness? Would situations where I am totally unaware of self, such as when asleep, affect the value I possess as a human being? And similarly to the higher cognitive functioning model, where would that leave the new-born baby, or comatosed ITU patient, or the hallucinating schizophrenic? Would people who have impaired or no self-awareness be less human as a result of their cognitive inferiority?

And on the converse, what of the people who do not self-identify as human at all, such as some of my psychotic patients who have the fixed belief of existing as a divine being. And if a robot was programmed to self-identify as human, would that endow that robot with the value of a human life?

Therefore for me, the libertarian view is too problematic to base our definition of humanness on it.


The Christian View: Divine Image-Bearing

So where does that leave us? I believe all of the major contemporary models of humanness bear some truth, but are all in some way dissatisfying and deficient. However, for me, there is a final model that I think gives the most complete and sufficient picture of what it means to be human.

Professor John Wyatt is professor of medical ethics at UCL, and a good friend and mentor of mine. He is also a Christian, and he proposes a model of humanness based upon his belief that humans are created by God in accordance to what it says in the bible:

“So God created man
in his own image,
In the image of God

he created him;
male and female
he created them”
(Genesis 1:26-27)

John Wyatt writes in his book “Matter of Life and Death”:

“Human beings are unique in all the vast array of creation because they alone of all creatures are made in God’s image…God has chosen no other image-bearer, animate or inanimate, on planet Earth…

In biblical thoughts, as each human life has a unique dignity because of the divine image, therefore each life has an incalculable and incommensurable value. In terms, and it is not possible to compare the ultimate value of one human life with another. Each human being is a unique masterpiece of God’s creation… In Christian thought, the dignity of a human being resides, not in what you can do, but in what you are, by creation” 5

The Christian doctrine of creation gives a remarkably complete and profound answer to what it means to be human. It states that being human is a spiritual profile that uniquely bears the divine image of our Creator God.

This means that we humans are not reducible simply to the product of our genome but our identity lies in our holistic created being. It means that that our worth is not tied to our cognitive abilities or capacities, but in our inherent, spiritual profile as an image-bearer of God. It means that that all humans are of equal value and standing, even when we differ in ability, social standing, and size of our cerebral cortex. And finally means that our lives have infinite intrinsic worth that exists independent of our own fluctuant views of self-worth.

Being an image-bearer of God gives us the rights to be valued and protected as precious and treasured creations of God, the responsibilities to uphold and respect others, the mandate to build an equal and cohesive society, and the authority to shape and care for the world.

The Story of Humanity

But furthermore, not only does the Christian worldview give a coherent and rich definition of humanness, it also goes one step further, and tells the story of humanness, from its ultimate origin to its ultimate destiny.

In the bible, we read that God made mankind in his image, and this original creation was flawless and perfect. Humanity was designed to live free from suffering, pain and death, and in perfect harmony and peace with each other, with the rest of creation, and with God. With mankind created, “God saw all that he had made, and it was very good” (Genesis 1:31).

However, humanity rebelled against God and chose to live life our own way, rather than submitting to the way God intended us to live- the bible calls this “sin”. And with our rebellion against God’s created order, humanity’s existence became imperfect and fallen, and we were cursed to live lives filled with suffering, pain and inexorable death.  We are still image-bearers of God, but that image is now broken and marred by our sin.

However, God, out of love for us, chose to redeem this frail and flawed humanity, through the remarkable act of God Himself entering our realm and becoming a human in the man of Jesus. In the incarnation of Jesus, God vindicated our human form as redeemable and intrinsically uniquely valuable.

Then in c.AD 33, Jesus died on a cross of crucifixion. The bible explains that in dying on the cross, Jesus took upon Himself all of humanity’s sin, and bore the punishment our sins deserve. And in doing so, He opened up a way for us to have our rebellion forgiven and for us to be reconciled to God, if we put our trust in Jesus as our Lord and Saviour.

And finally, three days after He died, the bible teaches that Jesus rose from the dead and made multiple public appearances, before ascending into Heaven. In His resurrection, Jesus showed us an example foreshadow of the final day of resurrection, when those who have trusted Jesus will also resurrect and live eternally in perfect joy and peace with God, with our fragile human states restored and brought to perfection.


What Does It Mean to Be Human?

Down the centuries and across the fields of thinking, many have tried to define humanness. Some based their definition on genomic profile, or high cognitive functioning, or self-determination. However, for me the most logically consistent and experientially relevant definition for humanness comes from the Christian worldview. The Christian model of humanness sees humans as divine and spiritual image bearers of God, who have intrinsic worth, inalienable rights, unique responsibilities, and an essential part in the ultimate story of the universe. I for one, rather like being human!



  1. Richard Dawkins, The Selfish Gene (1976), p.ix
  2. Donald MacKay, The Clockwork Image (1974), p40-44
  3. Peter Singer, Rethinking Life and Death (1995), p80
  4. Ronald Dworkin, Life’s Dominion (1995), p239, 155
  5. John Wyatt, Matter of Life and Death, (2009), p60-61