Biology

How Living Systems Violate the Second Law of Thermodynamics

When James Clerk Maxwell proposed the second law of thermodynamics, he envisioned a thought experiment in which two chambers of gas were joined by a small door under the control of a ‘demon’ who would selectively open the door depending on which direction the gas molecules were moving. If we think of the two chambers as containing mixtures of blue and red molecules, and they were randomly flitting about, the demon would open the door just as a red molecule was about to move into the right chamber or a blue molecule was about to move into the left. The door would remain closed otherwise. If such a demon were possible, Maxwell claimed, then it would be possible to convert disorder (i.e. the mixture of blue and red molecules) to order (the separation of blue and red molecules). Subsequently, however, it was felt that such a demon would itself create more disorder in the process of creating order, so, even if it existed, the second law of thermodynamics would not be violated. This post explores the assumptions underlying the second law of thermodynamics and challenges them.

A Living Cell

You could replace the two chambers in Maxwell’s thought experiment with a cell and its environment. The cell boundary is known to ingest useful material—e.g. food—and excrete the waste. The cell wall is porous, but its pores have the shape and form to allow useful stuff to enter and useless stuff to go out. Somehow the cell wall recognizes what is useful and what is useless. There is no demon who opens the gates to the cell, because the cell wall itself can recognize whether a molecule is useful or harmful, and selectively opens or closes the doors. The cell’s ability for pattern recognition is interesting, but to then recognize whether the alien is useful or harmful is a whole other level of complexity.

The mechanism for this ingress and egress of molecules involves proteins in the cell wall which undergo conformational change—i.e. they change form to bind to the food or waste—and transport it inside or outside the cell whereupon they are released. Conformational change is reversible; it is the molecule rearranging its structure to bind to the food or waste, and then rearranging itself to its original state. Since the process is reversible, it doesn’t violate the second law of thermodynamics. And yet it produces order from disorder (e.g. by excreting the harmful waste and ingesting the useful food).

The cell wall replaces Maxwell’s demon which needed a brain-mind to recognize, a hand to open or close the door between the chambers and have the evil intention to break nature’s law. One could suppose that this demon consumed energy and in the process of creating the order would produce a greater amount of disorder. But what if there is no demon? What if the boundary itself intelligent enough to open and close the doors selectively? And the process remains reversible?

The Distribution of Energy

To understand this problem a little better, we need to delve a little bit into physics. The laws of physics prescribe that the total energy is conserved, but they don’t fix the distribution of energy. The same total matter and energy could therefore be distributed differently, without violating physical laws.

In classical mechanics, the initial state from which the system evolved was an assumption. Nobody could say why the world is in this state when the conservation laws of physics allowed many other states. You could solve the equations of motion if you were given this initial state, but not otherwise.

In statistical mechanics, it was impossible to determine this initial state, so it was assumed that the system was potentially in all possible states. Indeed, the measure of disorder in the system was the total number of possible states, subject to the following conditions—(a) the total energy is constant, (b) the total number of particles is constant, and (c) the total volume of the system is constant. In short, underlying statistical mechanics—which rationalized thermodynamics on a mechanical thesis—was the recognition that the system could be in one of the many possible states. If the total number of possible states wasn’t increasing or decreasing, the entropy was supposed to be constant.

In quantum theory too, the state of a system is described by a wavefunction, but this wavefunction can be expressed through many bases each of which represents a different distribution of matter.

So, in every physical theory we recognize that there are many possible distributions of matter. The question is: Can we smoothly transform a distribution of matter into another? In short, if a system in distribution A transformed into distribution B, can we reverse this process by retracing the steps? Thermodynamics distinguishes between two processes—reversible and irreversible. The irreversible process is taken to indicate the thermodynamic arrow of time toward increasing entropy.

Linear and Cyclic Time

Imagine you were walking along a circular path, and you could only walk forward. If you took steps from A to B, and you could not go back, you could assert that the process is irreversible. But is it truly irreversible? You could keep walking around the same path and you will arrive at the original place because the path is circular. You haven’t retraced the steps, and you have still produced the same effect of retracing. Yes, while walking on a circular path, you cannot retrace your steps. So, the thermodynamic arrow of time holds. But you can still get back to the place where you started, in violation of the second law. Therefore, the second law of thermodynamics is identical to the claim that time is linear.

If time were cyclic, there would be no difference between reversible and irreversible processes. The reversible processes would just have a shorter cycle time, and the irreversible processes would have a longer cycle time; they would just seem to be irreversible on shorter measurable scales.

Does it mean that the milk that has been spilt on the floor will automatically get back into the bottle? Certainly not—you cannot retrace the steps. But it does mean that the milk will decay, form the food in the soil, from which grass will grow, which the cows will consume, and produce another bottle of milk. Matter will redistribute, from one state to another, until it restores itself in a previous state.

Biorhythms

If time is cyclic, then the second law of thermodynamics is only partially true—it says that time doesn’t go backward. What it doesn’t say is that change moves forward to restore its former state.

Living bodies and living ecosystems are examples of this cyclic pattern. Matter is transformed into useful products, then converted into waste, and then again converted back to useful stuff. There is a natural rhythm or pattern in which this happens. If we consume the natural products faster and transform them into waste faster than which nature can restore, then there will be abundance of waste. Under this wasteful consumption, there won’t be enough left to consume, and the consumers will die. Nature will then restore itself back to the previous state—over the due course of its natural cycle.

Our bodies operate in this cyclic manner. However, one important factor missing from current conceptions of biorhythms is that these are hierarchical, and they affect different people in different ways. Hierarchy means that there are faster cycles embedded in slower cycles. And time doesn’t act uniformly on each individual although time is cyclic. Without this understanding it is easy to misconstrue the existence of biorhythms as contrary to evidence, and therefore pseudoscientific.

Causality in Time

It is not enough to say that change is cyclic. We must also say that causality lies in time rather than in matter. In modern scientific theories, the causality—i.e. the force that pushes and pulls things—lies in matter. Similarly, this force acts uniformly on everything; you cannot have a selective interaction between two things. Quantum theory undermines these ideas. Two quantum objects interact through force particles—called bosons—which means that they don’t always interact; the interaction is the emission and absorption of a boson, which means that it doesn’t occur always. Similarly, because the boson exchange occurs when two systems are entangled—e.g. the energy lost must exactly match the energy absorbed because this energy is quantized—entanglement is a precondition to interaction. Due to these two factors, quantum theory cannot predict when and where the interaction occurs.

Then what causes the interaction? We need new forms of causality in science, and that causality can be time. Matter exists as a possibility, but time could convert this possibility into a reality, produce an entanglement, and cause the emission and absorption of interaction. The effect of time on possibility, entanglement, and emission are different, so their combination appears random, and this randomness makes us think that time is moving linearly, and its effects constitute random progress.

This new way of thinking, however, opens exploration into the causal nature of time. Matter in this view of reality is ‘inert’ or ‘passive’ because it exists as a possibility. The conversion of this possibility lies in time. Starting with John von Neumann, it has been hypothesized that quantum probabilities are ‘collapsed’ by consciousness which is problematic because if our choices were randomly interacting with matter then science could not make predictions about the future. A similarly hypothesis in which time collapses the wavefunction doesn’t suffer from this problem. But it requires overturning of centuries of thinking about time in which time is causally passive and matter is causally active.

Natural Creation of Order

It is widely supposed—under the linear notion of time—that the entropy (disorder) in nature will only increase. As things get more mixed up through their interaction, the total number of possible states of the universe will also increase. And that increase in possibility represents disorder.

There is however another way of thinking in which the increase in possibilities doesn’t change the order because the possibilities remain dormant unless converted into reality. We can in fact begin by assuming that the universe is the possibility of all that there can be, although only one of these possibilities is converted into reality at a given time—the causality of conversion remaining in time. Since the total number of possibilities includes everything, entropy is not growing or decreasing. On the other hand, the conversion of possibility into a definite reality makes the process a cyclical change.

In this cyclical change, time produces order and disorder, naturally. The universe is therefore not headed toward a ‘heat death’. It is rather undergoing a cyclic process of creation and destruction.