The Ricardian Machine, (Alien) Life, and the Rift Between – Part 1

Over Semester 2’s long Easter Break this year, I had the privilege to sit on a panel for the launch of Clair Quentin’s 2026 book Capital, Revenue and the Non-equilibrium Thermodynamics of Value. 

Since that probably sounds like a mouthful of sturdy concepts, I decided to break some of the book’s first part down in a two-part blogpost.

In my view, Quentin’s contribution in chapters 1-4 is two-fold. On the one hand they present a novel ontological characterisation of capital. In doing so, Quentin brings together neo-Ricardian/Sraffian economics and thermodynamics: a branch of physics that, simply put, studies the relationship between heat, mechanical work, temperature and energy. As we’ll see in Part 2 of this blogpost, this thermodynamic characterisation of capital results in an ontology that strongly resembles that of Life as we know it. With this similarity in mind, Quentin’s second contribution is an all-encapsulating and materially grounded account of what’s often called the metabolic (or ecological) rift. 

Broadly speaking, this is a concept used to describe the historical and ongoing shifts in how humans relate to the rest of the living world and how this is mediated by capital. In Part 1 of this blogpost, I’ll focus on Quentin’s physicalist approach to capital and introduce thermodynamic depth. Part 2 will apply thermodynamic depth to actual economic production and conclude with Quentin’s novel, perhaps even ‘alien’ conceptualization of the ecological rift.

Capital as the Ricardian Machine

To understand Quentin’s novel ontology of capital, it’s useful to rehash the prevailing ones. In neoclassical economics, capital represents the produced and necessary inputs (i.e. machines, tools, other materials) that are used in the production process of a given good or service. The accumulation of capital is typically seen as the primary driver of economic growth and is almost always measured in units of a given currency, say dollars or pounds. In Marxian economics, capital represents a unique and dynamic social relation. Instead of a fixed input, capital is treated as a continuous and self-expanding process of valorization that is enabled by the extraction of surplus labour as well as the generation and realization of surplus value. Both the identification of an appropriate measure and the actual measurement of this social relation is an enduring topic of debate among Marxists and, at least in my view, not exactly relevant for Quentin’s argument. 

This is because Quentin declares capital the ‘Ricardian Machine (RM)’ – a move that’s clearly anchored in neo-Ricardian/Sraffian economics and treats capital as an actual physical, rather than social or monetary, thing. According to this ontology, capital’s primary process is the production of commodities by means of commodities (PCMC). But Quentin’s ontology goes beyond PCMC where capital as a physical thing, now referred to as the RM, not only uses itself up, but in doing so, also makes itself grow in a physical way.

Quentin declares capital the ‘Ricardian Machine (RM)’ – a move that’s clearly anchored in neo-Ricardian/Sraffian economics and treats capital as an actual physical, rather than social or monetary, thing.

The Ricardian Machine as a dissipative structure

The claim that the RM uses itself up is rather straightforward and already addressed in both PCMC and biophysical economics. Material production processes that make up the RM depend on previously produced inputs i.e. raw materials, intermediate goods, physical machinery, infrastructure as well as worker’s consumption of goods and services. Quentin’s second claim on self-growth may sound obvious too but will strongly depend on the measure chosen to identify that output has grown from one period to the next.

Let’s do what economists love to do most and enter the realm of oversimplification. Consider coal and electricity as two commodities that make up the RM. Now let’s assume that in each production period, the RM uses 37.5 units of electricity and 80 units of coal in order generate 150 units of electricity. At the same time, 40 units of electricity and 16 units of coal are used to extract 80 units of coal. This means that each production period is subject to a surplus or net output equal to 150 units of electricity and 80 units of coal. Schematically, we’ll have:

If the technologies used for electricity production and the extraction of coal stay the same, we can claim that the RM grows with each subsequent production process because output exceeds the used up inputs. But we can only make this claim for each commodity individually and so the question then becomes: how can one compare and add up these physical quantities? Is a surplus of 1 unit of electricity, typically measured in kWh equal, to a surplus of 1 unit of coal, typically measured in tonnes? Physical accounting alone is unable to answer this question. And this is precisely where Quentin’s contribution becomes intriguing since they provide a thermodynamic, rather than monetary, answer. After all, if the RM was designated as a monetary object and we’d denote the surplus in terms of pounds, £150,000 worth of electricity and £80,000 worth of coal would simply amount to a £230,000 surplus each production cycle. In other words, the idea that money is used to make more money would hardly raise an eyebrow.

While the question of value in classical political economy may sound similar to Quentin’s search for an adequate measure to capture the RM’s growth, it’s not. Classical value theory is concerned with a measure that allows for the ratification of heterogeneous commodities as equivalents. This is done for the purpose of establishing a stable relationship between the surplus, in terms of that value measure, and profits denominated in exchange value or a currency measure. Quentin’s measure also aims to establish equivalence but not for the purpose of bridging the physical and monetary spheres. 

An adequate measure for Quentin’s objective must not only be a physical property of a given commodity produced in and by the RM but it should also be additive throughout changes to that commodity as it enters and exits other production processes. Although embodied labour and entropy are additive throughout changes in commodities, Quentin argues that neither is an actual physical property of commodities. Embodied labour exists as a measure of socially necessary labour time and is therefore a social construct rather than a tangible attribute that is physically embodied in commodities. 

To understand why entropy isn’t a suitable candidate either requires us to finally dive into Quentin’s thermodynamic approach. The RM is, after all, not just a physical thing but a dissipative structure: an open system which maintains its organisation through the continuous transformation of energy which then results in the emergence of complex patterns and absence of static equilibria.

One can think of a fluid heated from below: at low heat, the energy spreads evenly, and the system remains in a stable, predictable state (like a calm pond). But once the heat passes a certain point, convection cells – organised, swirling patterns that actively move the heat upward, cool down, and cycle back – suddenly appear. Dissipative structures are therefore subject to non-equilibrium thermodynamics where complex patterns emerge when the system is far from stability because it is continuously exchanging energy in order to maintain its structure. Quentin’s claim is that the RM is subject to these same features and therefore not just a physical thing but an object of physics, of thermodynamics. 

Entropy, thermodynamic depth and your room

Against this backdrop, Quentin argues that the appropriate measure for identifying RM’s characteristic process,  which is to use itself up to make itself grow, is a little thing called thermodynamic depth. Applied to a given dissipative system, thermodynamic depth refers to the gap between the system’s fine- and coarse-grained entropy. Entropy, in and of itself, is closely related to the second law of thermodynamics and its precise definition can vary throughout its application in different contexts. For our and Quentin’s purposes, however, what matters is the following: entropy refers to the amount of uncertainty vis-a-vis the exact location, speed and direction of travel of the various particles or objects a physical system is made of. The second law of thermodynamics posits that the entropy of a given system will either increase or remain constant throughout a given process; it will never decrease.

Applied to a simple and tangible system one can think of the natural tendency of your room to descend into clutter through the process of you living in it. As time passes, entropy increases since the many items in your room spread and scatter. This means that their exact location and direction of travel become subject to increased uncertainty or chaos unless energy is spent to re-organize them. Just like embodied labour, Quentin argues that entropy as is, is not an adequate measure for the exemplification of the RM’s characteristic process. While it always increases on the whole, it is not a stable property of commodities since entropy can  actually decrease in individual commodities for example when your clothing iron cools down.

Having clarified entropy, let’s get back to thermodynamic depth or the difference between constrained (fine-grained) and unconstrained (coarse-grained) levels of uncertainty and chaos. Let’s reconsider your messy room to hammer down this dense concept.

• Fine-grained entropy captures the uncertainty regarding all possible micro-level configurations i.e. all of the possible positions of every electronic device, sock, book, mug, etc. present in your room before you start tidying up. Crucially, fine-grained entropy is constrained and remains constant throughout the tidying process because cleaning does not destroy or create new micro-level information. In other words, all the arbitrary and disordered arrangements of your individual belongings that were possible before you started cleaning will still be there at the micro-level even as your room starts looking tidier. This constant and constrained amount of micro-level information doesn’t convey anything new about how the cleaning process is actually affecting the pile of clothes on your chair.
• Coarse-grained entropy, on the other hand, requires us to assess the uncertainty and level of chaos present in arbitrary snapshots of your room during the cleaning process. Consider a moment halfway through: you may have stashed away all of your belongings but the floor still needs hovering. Coarse-grained entropy considers all the possible ways each individual belongings could have been arranged to result in that particular state: a tidy room with a dirty floor. Unlike fine-grained entropy, coarse-grained entropy is unconstrained and therefore grows as the cleaning process unfolds. This is because each new macro-level state your room passes through in this process adds fresh useful information through the organisational rules that you have applied to get to this state: socks belong in the drawer, books go on the shelves, and eventually ‘floor needs hovering’.

To sum up: at the end of the cleaning process, coarse-grained entropy accounts for all the macro-level configurations consistent with each item in your tidy room, and its growth throughout the process reflects the fresh useful information added through each organisational decision you made along the way. Fine-grained entropy, meanwhile, remains what it always was which is a constant record of micro-level information about your individual belongings. Thermodynamic depth is the gap between the two: a measure of how much meaningful information has been added throughout the cleaning process.

Thermodynamic depth is the gap between the two: a measure of how much meaningful information has been added throughout the cleaning process.

In Part 2 of this blogpost I will proceed with an application of thermodynamic depth to the Ricardian Machine and present my interpretation of Quentin’s contribution as a novel and physically grounded account of the ecological rift.

Header image credit: Etienne Girardet via Unsplash.