How do you separate the real from the unreal?

Mike Brownnutt
Re-Assembling Reality
18 min readMar 10, 2021


We can try naturalism, materialism, and physicalism, but they leave us disappointed.

Re-Assembling Reality #16, by Mike Brownnutt and David A. Palmer

The Ultimate Reality is a term with strong religious overtones. Whether it is thought to be God, or Nirvana, or Brahman, or Death, there is something religious going on. Science also seems to concern itself with reality. It confronts the nature of reality in the lab, or wrestles with the nature of reality in its equations.

Reality, then, might provide a point of contact between religious practice and scientific practice. A first step in considering such contact is to pin down what might be meant by “real”.

There are three ideas related to science which are often thrown around as being synonymous with (or, at very least, in some way connected with) what is real. You know, what is properly real. Concretely, physically, really real. They are often held up by skeptics to demonstrate that the so-called realities of which religion speaks are not really real at all.

These ideas are naturalism, materialism, and physicalism. We will freely admit that there are (at least) as many interpretations of these ideas as there are philosophers working on them. But in this Essay we will take each in turn and attempt to sketch the shape of each, looking to see what each says, and to see what each can say.


In understanding this term, we might start with a simple dictionary definition:

Naturalism n.
A theory denying than an event or object has supernatural significance.

It’s just a rock. It has no supernatural significance. It’s natural. (Source: Jim Champion.)

This moves us a step forward, but it is only a very small step: “natural” means “not supernatural”. This might be progress, provided we can pin down what is supernatural. We might take two ways forward from here.

— To proceed inductively, we can list specific examples of natural and supernatural things, and then propose a general rule based on those examples.

— To proceed deductively, we can come up with a general rule regarding what is (super)natural, and then categorise specific objects according to that rule.

Both routes are standard in scientific reasoning, and there is often a certain amount of passing back and forth between the two: you start with a list, and make a rule, then you add to your list, then you modify your rule, and so on. Before we start with something difficult like “What is supernatural?” we can illustrate how the method works with an easier question like “What is me?”

What is ‘me’?

The entire universe can be divided into two types of things: ‘me’ and ‘not me’. It should be possible to categorise everything in the entire universe according to this scheme: My hand — part of me. Alpha Centauri — not part of me. Simple. From those examples, let us suggest a general rule:

Something is part of me if (and only if) it is part of my body.

We have admittedly changed the question from “What is me?” to “What things are part of me?” This should not trouble us. It is accepted practice in science, if the question looks tricky, to substitute it with a different question that looks similar but which is probably easier to answer. So we shall go with this new question.

What about my dental fillings? They are kind of part of my body. They are pretty firmly attached. But I am not sure they should be considered part of me. So I shall propose a new rule:

Something is part of me if (and only if) it has my DNA.

My hand contains my DNA and is part of me. Alpha Centauri and my fillings do not contain my DNA and they are no part of me. Good. Our new rule is working.

What about my nail clippings? They have my DNA. Now I have to choose: Do I grant that my nail clippings are part of me, and also grant that I am happy to throw parts of me away? Or do I insist that they are not part of me, and modify my rule? Neither path is inherently unreasonable. But let us take the latter path and propose a new rule:

Something is part of me if (and only if) it is part of my body and has my DNA.

My nail clippings were part of me, and stopped being part of me when I cut them off. Good. The rule is working.

The bacterial cells in or on my body outnumber ‘my’ cells by a significant margin. Are they part of me? Or I am part of them? (Source: Nicola Fawcett.)

What about my gut bacteria? It doesn’t have my DNA. But I would die without it. I simply would not function. Based on sheer numbers, bacteria living in and on me outnumber ‘my’ cells by about three to one. If they are not ‘part of me’, then it is sheer semantics to insist that they are bacteria living on me, rather than that I am a human living on them. Not wanting to put it to a vote that I would lose, let me accept that my gut bacteria are part of me. Accordingly, I will formulate a new rule:

Things are part of me if and only if they are part of my body and either have my DNA or are otherwise so integrated that without them I would die.


What about ‘my’ mitochondria? If you want to trace my ancestry, find out where I came from and who I am, you can look at my mitochondrial DNA. Mitochondrial DNA is good for tracing my ancestry because, unlike the rest of my DNA, it didn’t get mixed between my father and my mother; it got imported wholesale from my mother. As will as having strange rules for inheritance, it is a strange shapes in a strange place. Rather than having long strands in the cell nucleus (like the rest of my DNA) it comprises rings of DNA in the cell mitochondria. Why is it so strange? Because it’s not ‘my’ DNA.

About one and a half billion years ago, a cell absorbed a bacterium that turned out to be highly beneficial. The offspring of that bacterium have lived on symbiotically in almost every creature since. The very thing in me which can be used to track my genetic history is, in a significant sense, it is not carrying my DNA.

Were we just unlucky in our choice of problem, that we have such difficulty in settling on “What is me”? No. The problems we encountered here are ubiquitous. We face them in questions from “What is alive?” to “What is the moon?” If we start with general rules for categories, then we find specific examples later which do not fit well into the categories we have made. And if we start with specific examples, then these are of limited use in working out general rules that work in anything other than an after-the-fact kind of way. And if we alternate back and forth between new examples and new rules, then we keep going forever finding examples that don’t fit, and rules that we cannot accept.

We started here because it was supposed to provide an easy case study. We may not now be very hopeful that we will have more success with pinning down a delineation between what is natural and supernatural. But let us try.

What is ‘supernatural’?

Starting inductively, we can list some examples of supernatural things. We can see this at work when supernatural is defined as

Supernatural adj.
of or relating to God or a god, demigod, spirit, or devil.

Angels and demons. Buddha’s resisting the demons of Mara had supernatural significance. (Source: Wellcome Collection.)

Is this list exhaustive? Is everything not on the list natural? “Relating to spirits,” if broadly interpreted, might include angels and demons. And ghosts. And the soul. And maybe there is something supernatural going on in our minds. This fits with Webster’s more deductive approach of

Supernatural adj.
of or relating to an order of existence beyond the visible observable universe.

I can see a brain, but I cannot see a mind, just as I cannot see a spirit. Maybe we can be comfortable classifying minds as supernatural. Except the latest research in neuroscience insists that everything happening in the mind correlates to something going on in the brain. And the brain is natural. So the mind, as operations of the brain, is natural. Let us become uncomfortable with thinking of the mind as supernatural, and quietly move it over into the natural column.

Still, the direction of re-shuffling things doesn’t only go one way, from supernatural to natural. We used to think that purpose was entirely natural. Telos, final causes, were thought to be all part of the natural world. But now we have looked more closely. We find no atoms of purpose, indeed, we find no purpose at all. And we find that natural causes always precede effects. Any telos — any reaching out to the future, any purpose — must be provided from outside nature by some supernature. So just as we moved mind from supernatural to natural, let us move purpose the other way, from natural to supernatural.

Before this descends into a pick and mix of “put it wherever feels right for the moment”, let us see if we can find a surer footing by working deductively: from general rule to specific examples.

Richard Dawkins starts his book on The Magic of Reality by posing the question “What is Reality, What is Magic?” [1]. After all the trouble we have had with categorising things, Dawkins provides a clear and simple view of where the supernatural fits:

Supernatural magic is… fictional magic. … The supernatural… can never offer us a true explanation of the things we see in the world and universe around us.

Not only is this statement clear, it is strong. A supernatural explanation, says Dawkins, is not simply incomplete. It isn’t that supernatural explanations are restricted to metaphysical insights. Supernatural explanations are just wrong.

How can Dawkins be so sure that the supernatural cannot offer a true explanation of the world? He is pleasantly clear in his argument: The supernatural can never offer us a true explanation of things because the supernatural is a fiction. Anything which is not a fiction is not supernatural.

We once knew nothing of X-rays, but then new detection technologies allowed us to understand that they really existed. X-rays may be quite a different thing from atoms, but they exist. They are not fictional, so they are not supernatural, so they are natural. Simple.

What would happen if we one day developed a new detector which showed that ghosts really exist? What if ectoplasm turned out to be distinct from atoms and X-rays, but quite real? Not a problem: this would demonstrate that ghosts — which we would then know to be the true explanation of hauntings — are not fictional, so they are not supernatural, so they are natural.

What if we turn our new detectors beyond haunted houses and discover that demons, too are real? Not a problem. It would simply mean that demons — which turned out to be the true explanation of possession accounts — are natural.

How about God? Dawkins’ definition does not rule that God does not exist. It rules only that if God does exist, if He is not a fiction, if He really is the true explanation for the creation of heaven and earth, then Dawkins would call God natural.

A rose by any other name would smell as sweet.

Naturalism, it turns out, is so close to being tautological that it tells us nothing of significant help. Let us see what other options we have for pinning down what is real.


Let us return to our dictionary:

Materialism n.
A theory that matter is the only reality.

This seems easy enough. As soon as we have pinned down what we mean by matter, we are good to go. Fortunately, Webster is kind enough to cross reference this to its definition of matter. There are two that seem relevant.

Atoms are made of matter. Protons and neutrons in the middle, and electrons around the outside. But is that all there is? (Source: Billy and Lynn via flickr.)

Matter n.
material substance that occupies space, has mass, and is composed predominantly of atoms consisting of protons, neutrons, and electrons, that constitutes the observable universe, and that is interconvertible with energy.

A little reflection tells us that, while dictionaries are helpful for general conversation, they are rather blunt instruments for the philosophical conversations in which we must engage at present. One question that springs to mind is, if matter occupies space, what is space?

If space is matter, then matter is occupying matter. This seems to do something strange to our usual notion of what is meant by ‘space’ and ‘matter’.

Alternatively, if space is not matter, and only matter is real, then space is not real. This means that either matter is not occupying anything, or that it is occupying something unreal. In addition to doing something strange to our usual notion of ‘space’ and ‘matter’, this does something strange to our usual notion of ‘real’.

Alternatively, materialism wrong, and trivially so. And we didn’t even get to ask whether energy is also matter. It makes no sense to say that matter interconverts with matter. But it would be strange to say that matter interconverts with something that is not real. So maybe there really are non-material things that are real.

Alternatively, the lexicographers at Webster did not intend for us to think too hard about what they said, and we should take their definition with a pinch of salt. Maybe we should skip over this definition and see if the next one is more helpful.

Matter n.
the substance of which a physical object is composed.

If we accept that things like space and energy can be called ‘substances’, this definition can avoid some of the problems of the previous definition. But it has problems of its own.

A physical object — like a table or a chair — can be considered an object because all the pieces hold together. There are forces at work between the atoms. We may be happy to call energy a substance, given it interconverts with matter. But are we willing to call force a substance?

Still, we want force to be real. Consider a hammer. A hammer on its own does not cause you pain. A hammer hitting your thumb causes you pain. The hitting is a critical piece of the puzzle. If being hit by a hammer causes pain, then we must either accept that force is real, or we must accept that pain — indeed a broken thumb — can be caused by something that is not real.

If we are not comfortable saying that force is a kind of matter, and we are not comfortable saying that force is not real, then we must admit that there is more to reality than matter. We thus leave materialism and turn to physicalism.


Scientists are a pragmatic bunch, and have little time for philosophers. There is some idea they are trying to get to. If philosophers say that ‘naturalism’ is distressingly tautological and ‘materialism’ excludes more than we want to exclude, we pick a new word and hope we can do better with this one. Force may not be material, but it is definitely physical. Problem solved.

Rocks are physical. Ghosts are non-physical. Surely we can base some picture of reality on this distinction. (Source: Chris Warren via flickr.)

We shall say that all the things we think exist, or could exist, are ‘physical,’ and we shall call all the things that we think do not or could not exist ‘non-physical’. Rocks and atoms and force and information are all physical. Ghosts and consciousness and ESP and faster‑than‑light communication are all non-physical. If ever we change our minds, and decide that something that we previously thought impossible turns out to be entirely possible, we shall just stop calling it non-physical, and call it physical instead. We can make this work, surely.

Let us return to our dictionary:

Physicalism n.
a thesis that the descriptive terms of scientific language are reducible to terms which refer to spatio-temporal things or events or to their properties.

These definitions are getting longer, and this one might take some chewing. Let us take it a bit at a time:

Spatio-temporal things basically refers to everything that can be broken down into space (spatio), time (temporal), and mass (things). When physicists talk about different measurement systems, we don’t need to specify what we are measuring, because we know that: space, time, mass. What we need to specify is how we are measuring those three things. The United States uses the FPS system: foot (a unit for space), pound (a unit for mass), second (a unit for time). Most other places uses the MKS system: metre (space), kilogram (mass), second (time).

Space, which we struggled with under materialism, is clearly a spatio-temporal object. It is space. That is one problem solved. Now let us ask whether force is physical.

Isaac Newton told us that the force applied to an object is equal to the product of that object’s mass and its acceleration: F = m a. This can be reduced to space, time, and mass. (If you want the steps in between, here is a picture. If you don’t care, move on.)

Force can be reduced to terms of mass and acceleration. Acceleration can be reduced to velocity and time. Velocity can be reduced to space and time. So force can be reduced to mass and space and time. So force is physical. QED. (Source: David Pacey and the Authors.)

Force, being reducible to terms of space, time, and mass is physical! It exists! This fits with our intuition regarding hitting ourselves with hammers. Good.

Unfortunately, life is never quite that simple. Charles-Augustin de Coulomb told us that there is a force between two objects which is proportional to the product of the two objects’ charges, and inversely proportional to the square of the distance between them. The distance is spatial, so that is easy. But what is charge? This is where it gets tricky.

A lot of very smart people tried to reduce charge to a mechanical concept involving space, time, and mass. And they failed. Some people thereby concluded that charge was not real. An encounter with a Van de Graaff generator does for this argument what an encounter with a hammer does for force. We desperately want to say that charge is real. And yet we cannot reduce it to spatio-temporal things.

In the early days of research into electricity, some insisted that electricity was not real. It could certainly feel real though. (Source: Dickenson V. Alley via Wikimedia.)

But don’t panic! Our definition of physicalism is not yet done. Physical things must be reducible to reducible to “spatio-temporal things… or to their properties.” An electron is a a spatio-temporal thing. Charge is a property of the electron.

The day is saved! But wait! What other properties might spatio-temporal things have?

Is temperature a property of spatio-temporal things? Kind of. It is a statistical property of a macroscopic system in equilibrium. To say that with shorter words: a balloon full of air has a property, a temperature, which is not possessed by any individual atom in that system. Are we OK with that? Apparently. We are certainly OK enough to crown temperature as one of the seven base quantities in the International System of units (SI). That is about as physical an accolade as one could want.

Is luminous intensity a property of spatio-temporal things? Kind of. It is a measure of how bright something looks to a typical (whatever that means) human eyeball. This means that a source of ultraviolet light has a luminous intensity of zero (because a typical — i.e.white, adult, male — person cannot see it), and yet it might be quite visible to children (who are not as blind as forty-year-old men). Are we OK with that? Apparently. We are certainly OK enough to crown luminous intensity as one of the seven base quantities of the SI. I wish I was making this up.

Is happiness a property of spatio-temporal things? We have not defined a base unit of happiness. But on what grounds would we reject it? If Bob is a spatio-temporal thing, and Bob is happy, then happiness seems to be a property of a spatio-temporal thing. So either happiness is real, or we need to be more specific about what kinds of properties count as physical properties.

How about soulishness? Clearly, a naturalist, materialist scientist balks at the thought. But on what grounds can we a priori exclude the soul as not physical? Let us count the ways:

— It is not reducible to space, time and mass. So? Neither is charge. Charge is a property of electrons. Soulishness is a property of people. Where is the problem?

— Not everything has a soul. So? Not everything has a charge. This electron is charged. That neutrino is not. This baby has a soul. That rock does not. Where is the problem?

— The soul emerges from an interaction of the parts. So? Temperature emerges from an interaction of the parts. An atom does not have a temperature, and a fingernail does not have a soul. But a balloon has a temperature. And a person has a soul. Where is the problem?

— We don’t have a good way of measuring soulishness… Ah. Now we bay have hit the rub.

If only there were a good way to measure it

We have a good way of measuring time: we use a clock.
We have a good way to measure space: we use a laser.
We have a good way to measure mass: we use a set of scales.

We have a way of measuring temperature. It may or may not be considered a good way. Different understandings of temperature disagree over even basic things, like whether negative temperatures are possible. But our measurement methods are good enough for many practical purposes.

We have a way of measuring luminous intensity. It may or may not be considered a good way. It involves giving people eye tests, and pretending that this is not a strange way of doing fundamental physics. But our measurement methods are good enough for many practical purposes.

It is only relatively recently that measures for happiness have been developed. A lot of these measures rely on a person’s self-reported level of happiness,which is far too subjective for physicists to take seriously. Or it would be, if we could ignore the fact that the luminous efficiency function (by which we calculate luminous intensity) is established using questions like “Which looks brighter to you? The yellow light or the orange light?” But most physicists are very good at ignoring that fact, so we can, with a clear conscience, say that our measure of happiness is too subjective to really call it a good measure. And so we can say that happiness is not a physical property.

We don’t have any way of measuring the soul. We cannot see it, or weigh it, or photograph it, or make a detector which goes “ping” when a soul is nearby. This sets the soul apart from properties which we consider to be ‘physical’. And this gives us a handle on being more specific about what kinds of properties count as physical properties: We can measure physical properties.

At first glance, this seems both reasonable and unsurprising. If physicalism is the “thesis that the descriptive terms of scientific language are reducible to terms which refer to spatio-temporal things or events or to their properties,” and if empirical science has measurement at its heart, what could be more normal that the condition that we only count a thing to be physical if we can can measure it?

But at second glance we realise that “a thing which we can measure” has two constraints: the thing which is being measured, and we who are doing the measuring. We do not count a thing to be physical “if it is measurable”, in some platonic sense, because we do not know what may ultimately be measurable. Rather we count a thing to be physical “if we can measure it.”

The electroscope managed to measure electrical charge under carefully controlled conditions, and convince people that charge was physical. (Source: Wikimedia.)

Careful development of the eletroscope transformed charge from a thing which we could not measure into a thing which we could. A serendipitous event with photographic film changed X-rays from things which we could not measure to things which we could. Theoretical developments transformed quantum entanglement (Einstein’s “spooky action at a distance”) from a thing which we could not measure to a thing which we could.

In each case, the world around us did not change. The world does not care about humanity’s technological or theoretical break throughs. And yet it was our newfound ability to measure each of these things which led us to count them as being physical.

From this chain of reasoning we find that physicalism is not so much the claim that science limits itself to consideration of the physical, as that the physical is limited to what science can consider. And science’s ability to consider something is not some platonic notion independent of human ingenuity. What science can consider is intricately bound to what detectors humans can make to go ping. Far from looking outward and grounding a thing’s physicality in the world beyond us, we found ourselves also looking inward and tethering a thing’s physicality to ourselves.

How did we do?

We started this essay looking for ways to pin down what we mean by reality. We had three different approaches, each of which is on occasion bandied around as being synonymous with realism and synonymous with science.

Naturalism turns out to be tautological.

Materialism excludes more than people might be comfortable with.

Physicalism includes more than people might be comfortable with, not least in how much it includes us.

These attempts did not give us the handle that we might have been hoping for. In the next Essay we will return to the question of reality and see if we can do any better next time around.

[1] Richard Dawkins, “What is Reality, What is Magic?” in The Magic of Reality (2011).

This essay and the Re-Assembling Reality Medium series are brought to you by the University of Hong Kong’s Common Core Curriculum Course CCHU9061 Science and Religion: Questioning Truth, Knowledge and Life, with the support of the Faith and Science Collaborative Research Forum and the Asian Religious Connections research cluster of the Hong Kong Institute for the Humanities and Social Sciences.



Mike Brownnutt
Re-Assembling Reality

I have a Master's in theology and a PhD in physics. I am employed in social work to do philosophy. Sometimes I pretend that's not a bit weird.