The goal of this page is to serve as a dumping ground for the nubula of thoughts that have been dominating my thinking recently ( today is 7/19/2023).
I can readily trace the inception of this new tide of thinking to when I read Hoffman's pop science book "Life's Ratchet: How Molecular Machines Extract Order from Chaos." I was pointed towards this book by Thomas Varley, a graduate student in our Dept here at the time. The title attracted me. Though I knew that the book would focus on the dynamics of the nano-scale--how one protein interacts with the next--I was romanced by the idea that it might none the less provide a template for understanding something different. That something, if given a similar book title might be, "Cognition's Ratchet: How Neural Circuits Extract Order from Chaos." Emergent order, after all, what I imagine to be the primary function / purpose / characteristic of cognition. Could this book provide the key analogy needed to understand how the brain, as a cognitive system, makes sense of the chaotic world?
The book itself was a delight to read and I recommend it to anyone with even a fleeting interest in related topics. It began by introducing the puzzle of how life could possibly emerge from the wild and, presumably, chaotic storm that defines molecular dynamics. It highlighted the unlikeliness of this transition. Bolstered by a historical review of the numerous failed prior attempts to solve this puzzle, Hoffman provides a compelling introduction to quite how unlikely it is. Yet, the book swiftly shifts tone to a conciliatory tone - even a child's kitchen science project provides deep insight into the solution.
What makes life so unlikely is that it seems to break an immutable law of physics. This law states that disorder, like the 'house' in Vegas, always wins. From a distance life seems to break this law. Life creates order where there should be disorder. The highly organized states of matter that comprise living things fail to disintegrate. Yet, Hoffman explains that this, after all, is an illusion.
To offer a peak behind the illusion, it is useful to consider a simple (and tasty) children's science experiment: the physics of making rock candy. Making rock candy is simple: dissolve a generous supply of sugar into water, perhaps add a string or stick for the crystals to form along, and wait. The end result is that the dissolved sugar forms large sweet crystals resembling those found inside of a particularly fine quartz geode. The rock candy is not only fun to eat, it is also a useful tool for understanding how life can emerge from the chaos of molecular dynamics. The crystals themselves, like life, are highly ordered. To form the crystals, individual sugar molecules must settle into a precise lattice. Surely then this crystal structure, like life, illustrates that disorder does not always win. Yet, the same illusion is at play.
To understand why rock candy crystals actually reflect yet another win for the house, consider what happens at the boundary between the forming crystal and the sugary water. As we have said, the crystal is ordered. Remarkably, however, the sugar water is too. Each molecule of sugar organizes the surrounding water molecules. That is, the water molecules become organized by the sugar molecule floating among them. Without that sugar molecule, the water would be more disordered. The key is that sugar water is so much more organized than sugarless water that the increase of order in forming a crystal is less than the loss of disorder gained by removing sugar from the water. As such, there is more disorder in total, sugar crystal and water combined, after the crystal forms than was there in the sugary water at the start.
With this example in hand, it becomes reasonable to imagine where Hoffman is going in Life's Ratchet. One can start to appreciate that a bit of local order can actually increase disorder on a larger scale. In the case of life, this is the case. Organisms themselves may be very particularly organized but that this organization only survives by perpetually increasing the disorder of the organisms environment.
Consider, for example, how a cell survives. To live, the cells that make up plants and animals must contain mitochondria. These are the 'powerhouse' of the cell. Mitochondria provide that life giving energy by decomposing sugar. Looking at what goes into and out of this process demonstrates that life is sustained through the creation of disorder. Breaking down one sugar molecule requires six oxygen molecules. That is, seven molecules total go in to the process (one sugar and six oxygen). What comes out are 48 total molecules (six carbon dioxide, six water, and 36 adenosine triphosphate (ATP)). The specifics of what these molecules are does not matter as much as appreciating that there are fewer unique ways to arrange seven molecules than there are to arrange 48 molecules. More arrangements means more disorder. Thus, the mitochondria can be thought of as metabolizing order into disorder to enable cell life.
As his book continues, Hoffman follows this metabolism of order at the molecular scale to explain how life does not simply exist despite the law for increasing disorder but, rather, exists because of it. Life leverages the need for increasing disorder to make room for itself. His chapters are clear and delve steadily deeper into how this process enables the most fundamental of processes. He explains, for example, how it is that this process enables myosin, the most rachet-like element of cellular physiology, to transport goods from one part of a cell to another as though they themselves are living beings. By the end of the book, his thesis is clear and amply supported by colorful analogies and concrete examples explaining the functioning of the very cells that enable you to read the text.
What relevance does all of this have to cognition? I still don't have a clear answer. However, what is clear is that these ideas provide a template for understanding how systems can leverage gradients in order to do work. This, I imagine, is a gateway to understanding the neural basis of cognition. These ideas compel me to think of the brain as an oversized mitochondria, 'consuming' the statistics of an animal's environment as sensed through its means of perception and then 'metabolizing' the order out of those statistics to enable cognitive function. This, in turn, makes me wonder, What disorder was created to make room for that order? What order was lost in the generation of that disorder? What was the mechanism by which that disorder was created?
The related works of Karl Friston on free-energy and by Alec Boyd on information ratchets have clear relevance. It is possible that the theoretical foundations to understand how cognition emerges from neural systems rest in these works. I am looking forward to reading and considering these points further.