What Do Physics Theories Describe?

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Theories in physics describe the natural world at the smallest and most fundamental level. Perhaps that description isn’t yet complete, maybe there are inconsistencies to be resolved, but physics is steadily moving towards a comprehensive account of the foundational building blocks of reality; whether those ‘blocks’ turn out to be particles, strings, or some other exotic and as yet unimagined unit. This is, at least, what you might have been led to believe. Hopefully, by the time you reach the end of this article, whatever else you might think of physics theories, you will no longer believe they describe, or even aspire to describe, reality at the most fundamental level.

The Illusion of ‘Properties’ (I)

If you were asked to give a description of an electron, you might come up with something like, “An electron is a fundamental particle of nature with an electric charge of -1 and a mass of… well, a very small mass.” Good enough. What if I pressed you on this ‘electric charge’? Specifically, what if I asked how it could have a value of minus 1. “That’s easy,” you might reply. “All it does is describe the way the electron interacts with other particles and how it behaves in an electromagnetic field. If an atom has the same number of positively charged protons as it does negatively charged electrons, it will be electrically neutral; i.e. have an electric charge of zero. If it loses an electron, it will become a positively charged ion and interact with other ionised atoms in specific ways we can predict based, in part, on a calculation of these net charges.” Now that’s all well and good, but hasn’t actually answered my question, which was specifically about the meaning of a negative property.

By the time we complete our primary school education, we are all intimately familiar with the concept of negative numbers (although I remember being vexed by the rules surrounding their addition and subtraction at first), but it’s precisely this familiarity that has obscured just how absurd it is to claim that things in the real world, like electrons, could ever have them for properties, like a negative electrical charge.

 

Jean-Paul Sartre and Being-in-Itself

The immensely influential French thinker Jean-Paul Sartre (1905-1980) was famous for, among other things, distinguishing between two modes of being; being-for-itself and being-in-itself. The former was basically consciousness, while the latter was everything else. (At this point, you might be tempted to conclude this is just Cartesian dualism under a different name – hold off on that judgement for a moment though) Although there are two types of being, the only one that could be considered substantial (as in a substance proper) was the in-itself. The for-itself was literally nothingness, a perspective, a ‘hole’ in being. It makes no sense to call a literal emptiness, something, so for emphasis and clarity, Sartre called the for-itself, in contrast to being (-in-itself), non-being. We can now see that Descartes’ mistake, and the reason we ought not to accuse Sartre of Cartesian dualism, is that he treated consciousness as a substance. Sartre, on the other hand, while being an ontological dualist, is a substance monist. There are two types of being, but only one substance.

For now, I’d like to focus on being-in-itself; i.e. the natural, non-conscious world. Sartre describes the in-itself as a “plenitude of being,” meaning that it is purely positive in nature. Being “full” of existence in this way, it is impossible for the in-itself to contain any trace of negation. In seeking to capture this, Sartre says the in-itself is what it is, ‘being’ through and through. Think of an apple. It is complete in what it is, pure being. What if I eat half of it? Is the half apple now missing something? Has it gone from pure being to ‘half being’? Of course not. The half apple is still what it is; namely, half an apple. Of course, I, as for-itself, can compare it to the whole apple it used to be, and note a lack, but the substance before me isn’t lacking anything in itself. How could it? It just is what it is; a half-eaten apple.

 

The Illusion of ‘Properties’ (II)

My question then, how the electron can have a minus charge, was a reference to Sartre’s assertion that the in-itself is what it is, a “plenitude of being.” In this realm where things are, how can it possibly make sense to say a thing can have a negative property? Clearly, it can’t. If you lose a finger in an accident, we don’t say you have -1 fingers. If a balloon filled with helium rises, we don’t say it weighs -500 grams. Of course, we can say these things, but we don’t mistakenly think we are actually describing the person’s hand or the balloon as they really are. The hand doesn’t have a ‘property’ of -1, and the balloon doesn’t have a weight of -500 grams.

The initial response to the question tacitly admits all of this. In ‘explaining’ the negative value of the electric charge by referring to how the electron behaves and interacts with other particles, my imaginary interlocutor is acknowledging that the negative charge is a mathematical contrivance. It is a label that allows us to fit the electron into a mathematical theory that in turn, allows us to predict what will happen under certain conditions. ‘Charge,’ in other words, is a placeholder covering our ignorance.

 

A Thought Experiment

Imagine a special room containing a special pool table that has a variety of, you guessed it, special, coloured billiard balls on it. You aren’t allowed into the room, so you can’t actually touch any of the balls, but you are able to watch everything that happens through a window. In addition to the pool table, there is also a special being who lives in the room and will helpfully roll the balls about in any fashion you like. His name is Little Harry Copperfield.

Rolling up your sleeves, you ask Little Harry to roll a red ball into a yellow one. It hits it and rebounds, almost back to where it started. You take out your notebook and record this. Further experiments yield more results, such that you are able to begin to detect patterns in how the differently coloured balls interact with each other. Red balls always rebound off yellow ones, yellows always rebound off greens, and so on. To explain this, you invent a property called ‘rebound’ (‘r’) which describes a ball’s tendency to rebound off another ball. By assigning numbers to the different ‘r’ properties of balls, you can not only predict what will happen when two balls interact, you can do this even if you have never seen interactions of balls with those particular colours before.

The next day you come in to find Little Harry rolling balls from one side of the table to the other. Nothing particularly surprising happens until he flicks a red switch on the side of the table. Now, when he rolls the balls, some of them react in strange ways. Some veer sharply to the left, others to the right, while yet others seem completely unaffected. Time for that notebook again. As with the day before, after watching Little Harry through many trials, you are able to draw some conclusions. First, there doesn’t seem to be any connection between ‘r’ and the way these balls are affected by the red switch. A high or low ‘r’ doesn’t seem to correspond to anything happening in the room today. This necessitates a new property, ‘swerve,’ which determines how much a ball is affected by whatever change the red switch made to the table.

At the end of the second day, Little Harry asks you to give a description of a yellow ball (in much the same way I asked for a description of an electron). Pulling out your notebook, you confidently assert that it is a ball with an ‘r’ of 3.5 and ‘swerve’ of -7. When asked about what those ‘properties’ mean, you state that the first is a measure of how a ball interacts with other balls, and the second is a measure of how balls behave when the red switch on the table is pressed. Problem solved.

But is it “problem solved”? Do billiard balls really have these ‘r’ and ‘swerve’ properties? You talk as if they do, but when I push for an explanation, your answer carries us around in a circle. ‘r’ is only meaningful relative to other billiard balls, ‘swerve’ is only relative to the red switch and whatever it does. What do ‘r’ and ‘swerve’ actually mean about the billiard balls they supposedly describe? Do they describe topography? Texture? Weight? Mass? Internal structure? The amount of field curvature at the point where the billiard ball is located? You don’t know. In fact, you have no idea. While your arbitrary system allows you to make predictions and infer a lot about the behaviour of the billiard balls, it does all of this without telling you anything about the balls themselves.

 

The Illusion of ‘Properties’ (III)

Applying the lessons from the previous section, we can now see that the ‘charge’ of an electron, just like the ‘r’ and ‘swerve’ of the billiard balls, is only meaningful relative to other ‘charged’ particles and electromagnetic fields. What are electromagnetic fields? They are ‘areas’ around certain objects that influence the behaviour of electrically charged objects. Are we not going around in a circle here?

An explanation of a thing that turns away from the thing itself in order to make relative comparisons to other things is precisely the absence of an explanation. If you ask me to explain why Usain Bolt is so fast, and I launch into an exposition about the speeds of other top athletes in relation to Bolt, clearly you will be left dissatisfied. Why? Your question requires that I talk about Usain Bolt; his muscles, his training regime, his genes, etc. If I don’t do this, I haven’t answered you; I’ve merely covered over my ignorance.

 

So, what do physics theories describe? Far from describing reality as it actually is at the most fundamental level, they describe how elements of physical reality behave in relation to other elements of physical reality. In other words, they provide an abstract framework in which the ‘properties’ assigned to individual elements are supported, not by reference to anything pertaining to the element itself, but by reference to other elements. It’s turtles all the way down; only when you get to the last turtle, somehow you’ve arrived back at the first one.

One consequence of this complex, self-referential structure is that it is remarkably robust. Another is that it allows for truly impressive (and accurate) predictions and provides a correspondingly powerful method for intervention and manipulation of physical matter and forces. And it does all of this in spite of a third consequence; namely, that physics theories tell us absolutely nothing about what physical matter and the forces that govern their behaviour actually are. The properties that we think of as actually describing particles in some meaningful way: ‘charge,’ ‘spin,’ ‘flavour,’[1] even ‘mass,’ are nothing but arbitrary labels that depend for their validity on other particles/forces.

 

The ‘Work in Progress’ Argument (I)

Let’s say you agree that none of the ‘properties’ we meticulously ascribe to particles, or the theories we devise to organise these ‘properties,’ actually tell us what particles are. Can’t we at least say that we are working towards a complete and accurate description of what physical reality is? Aristotle took a first stab with his teleological account, then we got Newton who invoked forces acting at a distance, followed by Einstein and the curved geometry of space-time, until now we have the probabilistic weirdness of quantum mechanics. Each step brings us closer to total understanding, closer to a theory of everything.

 

Closure

Contemporary British philosopher, Hilary Lawson, has a theory, a theory about everything. It’s called closure (coincidentally, also the title of the book he wrote about it), and it says that the world is literally no-thing. Not nothing, as in emptiness or void, but no-thing, as in not any particular thing. He describes this no-thingness as openness and likens it to a bunch of dots randomly drawn on a piece of paper. If we look at the dots for long enough, we might begin to see shapes emerge; a face here, a car there, etc. The identification of a particular thing out of the background ‘noise’ is the process of closure and yields material (the object) and texture (openness within the material that permits further closures to be made). For example, the closure we make whereby we see a face in the background openness constitutes the material, and within that material there is more openness, which allows us to make further closures that make sense within our original one, perhaps, nose, eyes, mouth, etc. The openness of texture differs from the originary openness we associated with the world as a whole because it is contained within the material of a prior closure.

To be honest, I’m not exactly sure what I think about closure just yet. Parts of it are certainly compelling, others less so. Putting aside the theory as a whole for now though, it makes an interesting prediction that dovetails nicely with my argument in this article; namely, that science will never uncover the ultimate truth about the universe, the so-called theory of everything, not because science is inadequate or human minds are too feeble to understand the universe, but because there is no ultimate truth to discover. Ultimate reality isn’t a thing, it’s openness. We can never describe openness because descriptions are always, by definition, of things, and as we’ve seen, openness is no-thing. Lawson sees attempts to talk about openness as attempts to name the unnameable and associates this with the higher, more esoteric aspirations that lie at the core of most religions and some philosophers, such as Heidegger, Wittgenstein, and Derrida.

On Lawson’s account, all of the descriptions of reality we discussed above (from Aristotle to quantum mechanics) are merely different closures we can apply to the world, different ways of describing openness. No one picture of reality is closer to an accurate description than any other because such a description is impossible.

 

The ‘Work in Progress’ Argument (II)

Whatever you may think of closure (as I said, I’m not sure I’m completely sold on all of the specifics), Lawson’s conclusion seems to align with my own. Physicists aren’t in the business of describing reality itself, they’re in the business of modelling it. The thing about models is that there are always multiple ways to model any situation, and no single model is ever closer to the truth than any other because models have nothing to do with ‘truth’ or ‘reality.’ A model of the spread of ideas through a population that proceeds by treating the ideas themselves as the key vectors (so-called ‘memes’) is no nearer the truth than a model that takes the human beings having the ideas as the central vectors. Both are simplified, abstract descriptions of complicated, concrete events/things, and neither bears any genuine correlation to the actual human beings or ideas they are modelling.

What about the fact that modern physics theories are accurate to ever-bewildering numbers of decimal places, or allow for ever-more accurate predictions? Aren’t these evidence that we are getting closer to reality? Unfortunately not. All this shows is that we are refining the precision of our models (a particular strength of mathematical models, in fact, is that they lend themselves to this very type of accuracy), using ever better theoretical rulers, as it were. A model that can perfectly predict exactly which type of ideas will spread to each person in a population still doesn’t get any closer to telling us anything about the ideas or people as they are in reality.

In a similar way, given that none of the ‘properties’ we ascribe to the fundamental elements of reality tell us anything about those elements themselves, but simply allow us to organise them into theories that function as relational webs connecting elements to each other, identifying ever more properties of ever smaller elements is never going to somehow culminate in a complete description of reality itself.

 

Conclusion

Hopefully in this article I’ve given you a couple of reasons to, if not completely reject the notion that physics theories describe reality itself, at least doubt that this is what they’re up to in those lecture halls, laboratories, and Large Hadron Colliders of theirs. Let me close on a more positive note though. None of this means that physics theories are useless or ‘bad’ in some way. On the contrary, they are the most successful means we have ever devised for making sense of the physical world, and easily the most powerful tool we have for manipulating it. Indeed, it is a testament to the extraordinary success of these theories at bringing order to the confusing jumble of particles and forces that make up our universe, that we have been able to overlook, or forget, the inconvenient fact that they don’t tell us what that physical world actually is. With that said, the single idea I would like you to take from this article is not anti-science, but pro-science, just with a clearer idea of what science is actually doing, and a recognition of its limits.

 


[1] This is a property of quarks. There are six ‘flavours’ with completely arbitrary names; up, down, top, bottom, strange, and charm.

2 thoughts on “What Do Physics Theories Describe?

  1. Pingback: On the Unreasonable Effectiveness of Mathematics | Absurd Being

  2. Pingback: Neurophilosophy | Absurd Being

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