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Are We Just Machines Made of Meat?

Below is the script from my talk for UCL Christian Union Events Week in February 2024, titled "Am I Just a Machine Made of Meat?

Today we are looking at this very interesting question of “are we as human beings simply machines made of meat?”

And I’d like to begin with this book: “Homo Deus- A Brief History of Tomorrow” by Yuval Noah Harari. It’s the sequel to his bestseller Sapiens.

Harari begins Homo Deus by describing a hot drinks vending machine. I’m sure you’ve all seen these before- it’s an automated machine, you put your money in, you push the buttons, and then the pre-programme computer algorithm makes you a coffee.

Harari then goes on to write this:

“biologists have reached the firm conclusion that the man pressing the buttons and drinking the tea is also an algorithm… The algorithms controlling vending machines work through mechanical gears and electrical circuits. The algorithms controlling humans work through sensations, emotions and thoughts.” (Harari, 2015, pp. 98–99)

From the Enlightenment onwards, this idea that human beings are machines made of meat has become increasingly popular. I quite like the term “mechanical reductionism” to describe this view that everything that makes us human, including our thoughts, personality, decisions and beliefs are ultimately reducible to electrical brain activity and biological processes. We are ultimately just machines.

But is it true? Is this really the best explanation of our human experience?

Well this is where are going                   

  1. 4 Foundations of Mechanical Reductionism

  2. 3 Problems with Mechanical Reductionism

  3. 2 Possible Conclusions

Part 1: 4 Foundations of Mechanical Reductionism

So lets begin with the foundations of mechanical reductionism- this belief that humans are merely machines made of meat. Where does this belief come from? And I Have four foundations for you- and the first is this: the Enlightenment.

1. Enlightenment Philosophy

Now during the Enlightenment, philosophers such as Baruch Spinoza and Julien Offray de La Mettrie sought to push back against Rene Descartes’ idea the humans have both a soul and a body. Instead these Enlightenment philosophers argued that there is no human soul or spirit, and instead all human behaviour can be explained by physical bodily processes.


For example, La Mettrie described the human body as “a machine that winds itself up, a living likeness of perpetual motion”. La Mettrie proposed that various mental states were the results of the circulation of certain bodily fluids. Now many of his specific medical theories have been since proven wrong. However his principle, that human behaviour can be explained entirely by physical, biological process is still highly influential today, especially in light of modern advances in neuroscience, which is our second foundation.

2. Neuroscience & Neuroimaging

Now over the last few decades, there have been some major advances in neuroscience and neuroimaging that have given renewed credibility to the Enlightenment ideas of La Mettrie and Spinoza.

For example, the invention of fMRI and EEG machines, which are commonly used in hospitals today, have allowed scientists and medics to visualise brain activity that is linked with certain mental processes. There have been many studies that have linked electrical activity in specific parts of the brain to things like pain-sensation, love, ethical decision making, and even religious and spiritual experiences.

But the most famous of these experiments was the so-called “Libet Experiment”, named after the lead researcher Benjamin Libet. The experiment was done in the 1980s, and involved participants being connected to an EEG machine, whilst they carried out tasks involving making seemingly free decisions. The researchers found evidence that electrical brain activity associated with decision-making was detectable before the participant was consciously aware that they were making a decision.

Libet concluded that these findings called into question the reality of “free” choices, which actually appeared to be determined by prior electrical brain activity.

Now, we will be coming back to the Libet experiment later on.

But for now the point is that evidence from neuroscience and neuroimaging gives credibility to the belief that all human experiences, including seemingly free decisions, are determined by the electrical activities of the brain, perhaps in a similar way to a vending machine’s coffee production being determine by the buttons that are pressed.


3. Molecular Biology

Thirdly, we have the foundation of molecular biology.

Since the Enlightenment, there have also been several landmark findings in the field of molecular biology that have given further credibility to the idea that humans are merely machines made of meat. These key findings are namely Darwinian evolution and the structure of DNA.

In his famous book On the Origin of Species, Charles Darwin proposed that all life on Earth has evolved from a single common ancestor, through the principle of “natural selection”.

Nearly one hundred years later, James Watson and Francis Crick proposed their double-helical model for the structure of DNA, with its nucleotide bases which carry the information for producing proteins, organs and ultimately organisms.

These two landmark discoveries, of Darwinian evolution and the structure of DNA, have both transformed biology. And in addition, they have combined to produce the now popular view that humans are not just mere machines, but mere machines programmed for the sole purpose of propagating their genes. This is what biologist Richard Dawkins writes in his book The Selfish Gene:

“Replicators began… to construct for themselves containers… [Through evolution, these] survival machines got bigger and more elaborate, and the process was cumulative and progressive… They [replicators] are in you and in me; they create us, body and mind; and their preservation is the ultimate rationale for our existence… Now they go by the name of genes, and we are their survival machines.” (Dawkins, 1976, pp. 19–20)

Dawkins proposes that humans are merely machines built to propagate genes, and therefore all human behaviours and decisions are genetically programmed to fulfil this evolutionary purpose.

To continue the quote from Yuval Noah Harari mentioned earlier, in the eyes of the mechanical reductionist, a human is “like a vending machine which, if you press the right combination of buttons, produces another vending machine” (Harari, 2015, p. 98).

4. Artificial Intelligence

Our fourth and final foundation is the development of artificial intelligence.

So the argument goes: if humans are merely machines made of meat, and everything that makes us human can be reduced to our electrical brain activity, then it is only a matter of time before this electrical activity can be replicated in a machine made of silicon and steel. And hey-presto, we have a robot that is indistinguishable from a human.

In the 1950s Alan Turing proposed that a computer should be classed as “intelligent” if it can convince a human that they are interacting not with a computer, but with another human. This became known as the “Turing Test”, and it has been greatly surpassed in recent years.

Large language models such as ChatGPT, and AI chatbots like the one on Snapchat, can easily fool readers into thinking a text is from a human author. And AI systems are now being used in medical diagnostics, teaching softwares, weapons systems, and of course, social media algorithms.

These advances in AI, that have been able to replicate a whole range of human attributes, have strengthened the argument that humans are merely machines made of meat, because machines made of silicon and steel seem to be becoming increasingly human.

Part 2: The Problems with Mechanical Reductionism

So those are our four foundations of mechanical reductionism: Enlightenment philosophy, neuroscience, molecular biology and AI. And together, they build a pretty strong case that humans are just machines made of meat.

However, I think there are some big problems with mechanical reductionism, that make it basically untenable. And that’s what the next part of this talk is about- three problems with mechanical reductionism.


1. The Problem of “Nothing Buttery”

My first problem is what physicist Donald MacKay called “nothing buttery”.

In his book The Clockwork Image, Donald MacKay argued that a reductionist philosophy that aims to explain all of reality in terms of physical processes is guilty of the logical fallacy of “nothing buttery”.

MacKay explained that when someone offers a physical explanation for a phenomenon, it is an illogical leap to then say that the phenomenon can be entirely explained by nothing but this physical explanation.

One of the examples MacKay gives is of the LED advertising sign-boards in Piccadilly Circus. If you were to ask an electrician “what is on the board?”, the electrician may give a detailed description of the individual lights and the mechanisms which make them flash in a pre-determined order. Although this is true, it is of course an incomplete explanation of what is on the board. If the electrician adamantly asserts that the board is “nothing but” the mechanistic processes of the lights, and does not reference the words “Coca-Cola”, he has failed to fully explain the advertising board, and has committed the fallacy of “nothing buttery”.

And this applies to the scientific evidence we looked at in Part 1.

Even though neuroscience and evolutionary biology have discovered mechanistic explanations for many aspects of human behaviour, we cannot automatically conclude that human experience is nothing but the results of these biological processes.

If a part of the brain exhibits electrical activity when a person experiences love, or pain, or makes a decision, we can only conclude that the brain is involved in some way in these experiences. However, we cannot say that these experiences are entirely reducible to brain activity, in the same way that we cannot reduce the meaning of the advertising board in Piccadilly Circus to nothing but the mechanisms of the flashing lights.

In addition, it is worth elaborating a little further on the conclusions often drawn from the Libet Experiment we discussed earlier. The Libet Experiment showed that during seemingly free decision-making, parts of the brain associated with decision-making exhibited electrical activity before participants were aware that they are making the decision. Some, including Libet himself, concluded from this study that free will is simply an illusion, and what people think are free decisions are actually pre-determined by brain activity.

However, since the Libet experiment was published, lots of people have criticised various aspects of the experiment. Some people have pointed out that Libet relied on participants recalling the precise time they made the decision, to a precision of milliseconds, which is pretty impossible to do accurately.

Other people have pointed out that the Libet experiment only looked at a very specific and narrow type of decision- namely the decision to spontaneously move a limb.

However, even if the Libet experiment reliably and convincingly showed that brain activity precedes the conscious awareness of making a decision, it would not show that decision-making is caused by nothing but brain activity. Libet’s findings cannot rule out the existence of an immaterial mind or soul that freely makes decisions and then triggers electrical brain activity. Libet is guilty of committing nothing-buttery.

As mathematician John Lennox concludes: “It is one thing to say that the brain functions in certain ways like a computer. It is an entirely different thing to say that it is nothing but a computer.” (Lennox, 2020, p. 98)

2. The Problem of Consciousness

So firstly we have the problem of nothing buttery. But secondly we have the problem of consciousness.

Now consciousness is a notoriously difficult thing to define, but like neuroscientist Sharon Dirckx’s definition when she says consciousness is: “a property of the mind through which our subjective thoughts, feelings, experiences and desires have their existence”. So it’s first-person, subjective, mental experience of being ourselves. And clearly this is something we all experience.

However, it is very difficult to find a reductionistic explanation for consciousness that relies only on electrical brain activity. How can electrical brain activity produce the subjective first-person awareness of self that humans experience?

To put it another way, getting consciousness from electrical brain activity is the equivalent of suggesting that if we increased the complexity of the circuits in a drinks vending machine, we’d eventually produce a vending machine that is aware that it is making coffee.

Even Yuval Noah Harari acknowledges:

“Scientists don’t know how a collection of electric brain signals creates subjective experiences. Even more crucially, they don’t know what could be the evolutionary benefit of such a phenomenon. It is the greatest lacuna in our understanding of life.” (Harari, 2015, p. 128)


This problem of consciousness has led some mechanical reductionists to suggest that consciousness is simply an illusion. For example, philosopher Daniel Dennett describes consciousness as “like stage magic, a set of phenomena that exploit our gullibility, and even our desire to be fooled, bamboozled, awe-struck” (Dennett, 2003).

However, I would argue that appealing to illusion to explain consciousness is actually a self-defeating view.

If you think about it, if all consciousness is an illusion, it would logically follow that all beliefs produced by the human consciousness are illusions and untrustworthy. Why should I believe anything that this illusion is coming up with? And this would call into question the entirety of science, philosophy and the belief that consciousness is an illusion.

As biologist J. B. S. Haldane puts it:

“…if my mental processes are determined wholly by the motions of atoms in my brain I have no reason to suppose that my beliefs are true. They may be sound chemically, but that does not make them sound logically. And hence I have no reason for supposing my brain to be composed of atoms.” (Haldane, 1927, p. 209).


3. The Problem of Free Will

Thirdly and finally, mechanical reductionism raises a range of problems around the topic of free will.

If humans are merely computers made of meat, then no decision or action that a human makes can be classed as “free”, for all actions are predetermined by electrical brain processes that are ultimately programmed by evolution.

No matter how complicated a vending machine is, it can only do what it is programmed to do, and therefore it is not free to make decisions about what drink it is going to produce. Similarly, a worldview that reduces humans to merely machines made of meat has to jettison all beliefs in free will.

Here’s Richard Dawkins again: “DNA neither cares nor knows. DNA just is. And we dance to its music” (Dawkins, 1995, p. 133).

However, all of us have an experience of free will that seems undeniable. Most people have a powerful awareness that they are free agents who can make decisions at will, and are not pre-programmed robots.

In fact, I would argue that our entire society is built on the assumption that free will exists.

Science and philosophy rely on the idea that humans can choose to change their beliefs based on new evidence or insights.

Politics is built on the idea that humans can choose both who to elect and how to govern.

Commerce and economics assume that humans can decide how they spend their money.

The arts are built on the idea that people can choose how they express themselves.

The modern social justice movements such as feminism or Black Lives Matter are built not only on the assumption that personal autonomy is real, but also that it is of paramount importance in civilised society.

But perhaps the most important area that is underpinned by the assumption that free will is real, is: morality.

If humans are merely machines made of meat, who simply enact what they are programmed to do, the concept of holding someone morally accountable for their decisions, or enforcing justice on moral wrong-doing, is logical absurd. Enforcing moral justice on a machine made of meat would be the equivalent of sending a vending machine to prison for dispensing the wrong drink.

And so in order to believe in mechanical reductionism, you would have to abandon any belief in moral good and evil, and any idea of justice or accountability for wrong-doing. And personally I don’t think this is sustainable. I certainly haven’t come across anyone able to live that way. Even advocates of mechanical reductionism such as Yuval Noah Harari or Richard Dawkins are often on the airways or in their publications expressing their moral opinions.


3. 2 Possible Conclusions

And so in summary, I think there are some huge problems with mechanical reductionism, and we’ve looked at three of them: the problems of nothing buttery, consciousness and free will.

So what now? Where do we go from here?

Well I want to end with two conclusions- two possible steps from here.

The first conclusion is one we’ve already looked at- the conclusion that humans are indeed machines made of meat, but therefore we have to abandon our beliefs in consciousness, free will, justice and moral accountability. And it means we have to ignore the logical problems with this view that we have already gone through. And as I mentioned, I do not think this position is practically sustainable.

So is there an alternative? Is there another way we can reconcile the findings from neuroscience and molecular biology with things such as free will, consciousness and justice?

Well I would want to suggest that I think a more compelling and coherent view of our humanity can be found in the Ancient text of the Bible, which presents humans as: more than machines made of meat.

In the first book of the Bible, Genesis chapter 2, we read this:

“Then the Lord God formed a man from the dust of the ground…”

Here we have the account of God creating humans out of matter, or “dust”. The original Hebrew literally means “Earth stuff”. In the Christian worldview, we are physical beings with DNA, muscles and electrical brain activity.

However, that verse doesn’t end there. It goes on:

“Then the Lord God formed a man from the dust of the ground and breathed into his nostrils the breath of life, and the man became a living being”.

In this quite mysterious image, we see God taking the human body and adding something more- breathing in a human spirit, that turns the human body into a human being. In Hebrew the word breath and spirit are the same word “neshamah”. And in Christian thinking is it this human spirit that is the seat of consciousness, and moral awareness, and free will.

Now there is plenty debate amongst Christian theologians around whether these events literally happened in time, or whether they are more poetic allegorical descriptions of the creation of humans. But whichever is correct, the main point of this verse is that humans are created by God as both physical and spiritual beings. We are more than just our electrical brain activity.

And then, as the Bible’s story unfolds it culminates in the audacious claim that the God who created humans became a human. In history, 2000 years ago, the Bible says that God was born as the baby Jesus on the first Christmas day. Here are some classic verses often read out at Christmas Carol Services-

“All this took place to fulfil what the Lord had said through the prophet: “The virgin will conceive and give birth to a son, and they will call him Immanuel” (which means “God with us”).” Matthew 1:22-23

And in becoming a human himself, God gave His ultimate vindication of the value and dignity of human beings.

Here is medical ethicist John Wyatt:

“Christians treat the human body with special respect. Why? Because this strange and idiosyncratic collection of 35,000 genes, 10 billion nerve cells, several miles of wiring, eight metres of intestinal plumbing, five litres of blood, and assorted biochemical engineering- this is the form in which God became flesh!... When Christ is born and raised as a physical human being, God proclaims his vote of confidence in the created order.”

You see, the value of a machine is determined either by what it can do, or what it is made of, or how much other people value it. So a car is valuable if it works. And if it doesn’t work, it can be sold for parts. And for some people, cars have sentimental value even if they don’t work.  

However in the Christian worldview humans are much more valuable than our productivity, or our component parts, or how much other people value us. We are more than just machines made of meat. We are valuable because we are both spiritual and physical beings created by God, and because God chose to become one of us.

And so let me end by asking, which conclusion do you think is better: the mechanical reductionist view that says we are machines made of meat, or the Christian view that says we are created by God as physical and spiritual beings?

For me, I think the Christian view is so much more compelling, for it gives coherent grounding for our beliefs in consciousness, free will and moral accountability, whilst also upholding the discoveries of neuroscience and molecular biology. And it gives human beings an inherent dignity and value that mechanical reduction fails to offer.

Or to put it in the words of the robot ‘Optimus Prime’ in the film Transformers:

“Humans… there is more to them than meets the eye” (Bay, 2007).


Bay, M. (2007) Transformers. United States: Paramount Pictures.

Darwin, C. (1859) On the Origin of Species by Means of Natural Selection, or the preservation of favoured races in the struggle for life. London: John Murray.

Dawkins, R. (1976) The Selfish Gene. Oxford: Oxford University Press.

Dawkins, R. (1995) River out of Eden. London: Basic Books.

Dennett, D. (2003) ‘Explaining the “Magic” of Consciousness’, Journal of Cultural and Evolutionary Psychology, 1(1), pp. 7–8.

Dirckx, S. (2019) Am I Just My Brain? Oxford: The Good Book Company.

Haldane, J. B. S. (1927) Possible Worlds and Other Essays. London: Chatto & Windus.

Harari, Y. N. (2015) Homo Deus- A Brief History of Tomorrow. London: Penguin Random House UK.

Lennox, J. (2017) Determined to Believe: The Sovereignty of God, Faith, and Human Responsiblity. Oxford: Lion Hudson Limited.

Lennox, J. (2020) 2084- Artificial Intelligence and the Future of Humanity. Grand Rapids, Michigan: Zondervan Reflective.

Libet, B. et al. (1983) ‘Time of conscious intention to act in relation to onset of cerebral activity (readiness-potential): The unconscious initiation of a freely voluntary act’, Brain, 106(3), pp. 623–642.

MacKay, D. (1974) The Clockwork Image- A Christian Perspective on Science. London: Inter-Varsity Press.

La Mettrie, J. O. de (1747) Machine Man. Translated by Jonathan Bennett, Early Modern Texts. Available at:

Turing, A. (1950) ‘Computing Machinery and Intelligence’, Mind, 59(236), pp. 433–460.


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