Stuart Kauffman (2008)
INTRODUCTION: From the point of view of consciousness studies, Kauffman’s ‘poised realm’ is the most interesting aspect of his work. He identifies the poised realm with conditions in photosynthetic organisms where quantum coherence begins to decohere, but is forced back into partial coherence. His hypothesis is that consciousness is found in this border area of decoherence and recoherence, which is suggested to have the potential to supplement the deterministic algorithms of classical physics.
Kauffman is critical of the reductionist trend of science as practised during the last three centuries. He argues that reduction of the world to particles in motion does not by itself supply sufficient explanation in all instances. He holds that the organisation of complex areas such as evolution and biology cannot be deduced just from the existence of particles and their governing laws.
Kauffman further argues that given the basis of the physical laws, there is an infinite number of ways in which the quanta could be arranged, of which, the organisation of proteins and organisms is only a very limited subset. So the evolution of the present life forms is not a deterministic certainty, and the existing life forms and other aspects of the material world are only a small subset of the possible outcomes.
Origin of life:
Kauffman hypothesises that life originated from a simpler replicator than either DNA or the now popular idea of RNA. A helix of 32 amino acids, has been shown to be capable of binding together two smaller chains of 17 and 15 amino acids, and thus forming a copy of the initial sequence of 32 amino acids. If substantiated, this would demonstrate an emergent system of replication. Furthermore it is implied that many molecular systems could achieve this, so there are many paths to the origin of life that are allowed by the laws of physics, rather than a single deterministic path.
Life, even it is argued primitive life, involves agency which does not exist in physics. Agents are seen as emerging from the evolutionary process. Life is seen as introducing agency into the universe, and agency in its turn introduces meaning and value. The act of choosing between different types of behaviour is seen as requiring an agent. But in physics there are no such agents.
It should be stressed that Kauffman’s position appears to be different from what might be termed the ‘naïve emergent property theory’, which has been a prominent theme in mainstream consciousness theory. This merely asserts that consciousness is an emergent property without showing how it emerges from a more fundamental level, as can be clearly demonstrated for other emergent properties such as the liquidity of water.
Far from thermal equilibrium:
Kauffman argues that to understand agency it is necessary to understand the Carnot work cycle in thermodynamics. The work-cycle system consists of a hot and a cold reservoir, plus a cylinder and piston with a compressible gas. Heat from the hot reservoir expands the gas and pushes the piston down the cylinder. The piston is pushed down the cylinder until the gas cools, and contracts again as a result of the cold reservoir at the other end of the cylinder. This power stroke is described as spontaneous because it does not require the injection of any energy into the system. A ball rolling down a hill is another example of spontaneous action. What does require an injection of energy is pushing the piston back up the cylinder, and this process is described as non-spontaneous. In other words, the system has to be reset. The usefulness of this type of steam engine is that it takes less energy to recompress the cooled gas than the amount of energy obtained from the hot gas.
The image of the Carnot steam engine is important in relation to the functioning of biological tissues, because these are both systems far from thermal equilibrium. The Carnot engine cannot work within a state of thermal equilibrium because it requires the heat on the cylinder to expand the cooler gas. It is stressed that in both the steam engine and organic processes, there is a need to reset the mechanism so that it can continue its work cycle.
Agency is seen as the biological feature that allows resetting of the work cycle. Kauffman examines the primitive example of a bacterium swimming up the glucose gradient. Receptors for glucose signal the glucose gradient. For the bacterium the meaning of the gradient signal is more glucose in a particular direction, and the bacterium interprets this meaning by swimming up the gradient.
Kauffman is critical of the concept of ‘information’ as applied to organisms, claiming that the concept is both restrictive and unclear. He points out that Shannon conceived of information as involving a source, a channel and a receiver. Information sent down the channel reduces the uncertainty of the receiver. It is pointed out that Shannon never defines information, but leaves the ‘receiver’ to decide this. A bacterium is seen as a receiver of information about the glucose gradient, and it responds to the information. Kauffman argues that the information approach ignores the physics of work and energy, and focuses narrowly on information transmission from DNA to RNA to protein. He regards this as being inadequate to explain the functioning of the cell.
Kauffman views the role of the cell as being to constrain activity so there are only limited degrees of freedom, and this constraint requires work to achieve it. In the steam engine, it requires work to assemble the piston and cylinder that provide constraints. Cells are thus seen as building their own constraints or boundary conditions. Organisms are viewed as an interwoven web of work and constraints.
It is further argued that information involves an agent, and that this agent is a constraint, so that the information is given meaning or interpretation. The advantage here is that there is not just one response to one stimulus as in an automation, but a choice of different responses according to context. The ability to discriminate between stimuli is argued to be a state poised between order and chaos, where order always gives the same answer for stimuli, despite varying outcomes from these stimuli in the past, and chaos gives a random outcome that is of no value. Kauffman’s approach resonates with other recent research on brain areas such as the orbitofrontal, anterior cingulate, the basal ganglia and also the function of dopamine. These are important in providing the brain with a flexibility in its response to stimuli which could not be prestated because of the enormous number of possible outcomes.
The problem with computers:
In the foundational stage of computing, Alan Turing understood that he could write down symbols, modify then according to a set of rules, and eventually after perhaps a series of such modifications, come to an answer. Turing reconstituted this process as an idea for a machine that read symbols on a tape and made a rule-governed move, according to what the symbol was. It transpired that this machine could carry out all possible computations.
The computing/algorithmic systems, to which this approach gave rise, have had some successes at the level of robotic machinery. With defined objects in a defined setting, algorithmic systems can solve specific problems, such as a robot finding a source of electricity in a room. In this case, the solutions for the robot have been prestated, or predefined by the programmers, who know how it should respond to objects in the room. However, it is not possible to prestate all the conditions that may be faced by humans and other complex organisms. This would lead to an explosion in the number of possibilities that needed to be precalculated. The robot is provided with a frame limitation, but the explosion of options suggests that this is not feasible for humans which in turn suggests the brain is at least in part non-algorithmic.
Kauffman also looks at the problem of categorisation. Humans place things in categories all the time, and two very dissimilar things can be consigned to the same category. Thus robins and penguins are both in the bird category. Plato was possibly first to discuss the problem of categories, suggesting that members of categories shared at least one essential feature. Wittgenstein, however, argued that categories might have no common features. This leaves us to look for similarities but it is not clear which similarities allow membership of which category. A bird may be the same size, weight and colour as a ball, but that does not put the ball into the bird category. Kauffman suggests that these difficulties may be overcome if categorisation is non-algorithmic.
Consciousness & the poised state:
In the final stage of his book, Kauffman argues that consciousness derives from a ‘poised state’ between quantum coherence and decoherence into classical states. He looks to the transition from a quantum world of persisting possibilities to a classical world of actual possibilities. The acausal nature of quantum mechanics is central to his thinking. The Schrödinger equation is solved for the amplitude of the electron at each point in space. These eigenfunctions square the amplitude at each point in space, and define the probability of finding an electron at each point in space. Nothing known causes the electron’s choice of position, there are only probabilities at every point in space. For Kauffman, quantum mechanics breaks out of the causal closure of the reductionistic tradition. Amongst other things he suggests that this might resolve the problem of freewill, which cannot exist within deterministic physics.
Kauffman discusses the concept of phase information. The interference pattern seen in the two-slit experiment requires all the phase information on the final screen to add together to give the peaks and troughs of the interference pattern. Decoherence involves the loss of phase information as a result of interaction with the environment, often described as a heat bath of quantum oscillators. The interaction with the environment in seen as comparable to the interaction with the measuring device in the Copenhagen interpretation. However decoherence may not be as clear cut as the Copenhagen type measurement. In certain circumstances, only part of a system decoheres and some coherence remains.
Kauffman places consciousness at this ‘poised state’ where part of the system decoheres and part is coherent. The coherent state is suggested to influence the classical decoherent state. In looking for such a system, Kauffman examines the recent research on photosynthetic systems. In photosynthesis photons are captured by the chlorophyl molecule that is held by antenna protein. The chlorophyl molecule maintains quantum coherence for up to 750 femtoseconds. This is longer than the classical prediction, and is viewed as responsible for the higher than classically predicted efficiency of energy transfer. The antenna protein plays a role in preventing more rapid decoherence, or in inducing recoherence in decohering parts of the chlorophyll molecule. Part of the quantum system may start to decohere, but be forced back into coherence, sometimes described as quantum error correction.
Within the chlorophyll molecule the superposition of the Schrodinger solutions allows the simultaneous exploration of all the possible pathways. This is more efficient than the serial or one-path-at-a-time exploration, and is taken as an explanation for the mid 90 percentage efficiency of the system, in contrast with the 60-70% predicted for a classical system.
Kauffman thinks that the system seen in the chlorophyll molecule raises the possibility that webs of quantum coherence or partial coherence can extend across a large part of a neuron, and can remain poised between coherence and decoherence. Kauffman’s discussion refers to coherent electron transport, but he recognises that other forms of coherence such as phonons and electron spin could be relevant.
The ‘poised state’ is supposed to span states that are between being mainly coherent and partly decoherent. Information injected into the system can induce recoherence. The flow of information into cells is seen as a means by which recoherence could be induced and coherence maintained. In other writing, Kauffman suggests a two-way flow of influence, with quantum possibilities effecting classical systems, while classical systems could influence recohering quantum systems.
In relating quantum coherence to consciousness, Kauffman assumes like Hameroff that coherence would have to be sustained for the milliseconds timescales associated with neural processing, rather than the femto and picosecond timecales associated with quantum coherence in photosynthetic organisms. It might be debatable if a direct one-to-one correlation between processing activity and conscious episodes is necessary.Tags: Kauffman Posted by