Ilya Prigogine

The future is uncertain... but this uncertainty is at the very heart of human creativity.

Summary

Ilya Prigogine (1917 - 2003) was a Belgian physicist and Nobel Laureate chemist noted for his work on Dissipative Structures, Complex Systems, Chaos and Irreversibility.

His ideas influenced the concept of the Unity of Chaos/Order (see Vital Unconscious and Biocentric Principle).

Ideas

• Broken Second Law of Thermodynamics - Under certain circumstances, the Second Law of Thermodynamics (which predicts the relentless increase of disorder - Entropy - within a given system) might be broken. This implies that the universe is not necessarily doomed to a long, slow slide into "heat death" in which all useful energy would be lost in random motion.
• Dissipative Structures (Self Organisation) - open systems, in which an exchange of matter and energy occurs between a system and its environment.
• Renewal of Nature - Man can enhance his environment by means of careful interventions within dissipative structures in such fields as food supply, disease control or bio-engineering.
• Order out of Chaos - there are chemical reactions in which the molecules adjust their behaviour not only to local circumstances but also to the larger parent organisation, the classic example being crystal growth.
• Arrow of Time - time goes forward and is irreversible, which contradicts the belief that time is an illusion.

The Second Law of Thermodynamics

Thermodynamics is the branch of theoretical physics which deals with the laws of heat motion, and the conversion of heat into other types of energy. The word is derived from the Greek words therme ("heat") and dynamis ("power"). It is based upon two fundamental principles originally derived from experiments, but which are now regarded as axioms.

The first principle is the law of the conservation of energy - energy can be transformed in different ways, but can never be created or destroyed.

The second principle states that Entropy (the ratio of a body's energy to its temperature) always increases in any transformation of energy. This is generally understood to signify an inherent tendency towards disorganisation.

Prigogine was able to show that that nonlinear systems under certain conditions may evolve toward macroscopic order, thus apparently breaking the Second Law of Thermodynamics.

Dissipative Structures (Self Organisation)

Dissipative Structures are nonequilibrium thermodynamic systems that generate order spontaneously by exchanging energy with their external environments. They include:

• physical processes (eg whirlpools),
• chemical reactions (eg Benard cells - convection cells that appear spontaneously in a liquid layer when heat is applied from below), and
• biological systems (eg cells).

Prigogine's research showed that all complex biological systems contain subsystems that operate far from equilibrium (Homeostasis) and continuously fluctuate. At times a single fluctuation or a combination of them may become so magnified by possible feedback, that it shatters the preexisting organization. At such revolutionary moments or Bifurcation Points, it is impossible to determine in advance whether the system will disintegrate into Chaos or leap to a new, more differentiated, higher level of order.

The most intriguing application of his ideas is to the origin of life and biology generally.

Order out of Chaos

In order to solve the problem of stability far from equilibrium, Prigogine did not study living systems, but turned to the much simpler phenomenon of heat convection, known as the Benard Instability.

• When a liquid is uniformly heated from below, a constant flux heat is established, moving from the bottom to the top. The liquid itself remains at rest and the heat is transported by conduction alone.
• When the temperature difference between top and bottom surfaces reaches a certain critical value, the heat flux is replaced by heat convection, in which the heat is transferred by coherent motion of large numbers of molecules.
• At this point, a very striking ordered pattern of hexagonal cells appears, in which hot liquid rises through the center of the cell, while the cooler liquid descends to the bottom along the cell walls.
• The Benard instability is a spectacular example of spontaneous self organization.

Another amazing self-organizing organization phenomenon, studied extensively by Prigogine, are the so called Chemical Clocks.

• These are reactions far from chemical equilibrium, which produce very striking periodic oscillations.
• For example, if there are two kinds of molecules in the reaction, one 'red' and one 'blue', the system will be all blue at a certain point, then change in colour abruptly to red, then again to blue, and so on, at regular intervals.
• Different experimental conditions may also produce waves of chemical activity.
• To change colour all at once, the chemical system has to act as a whole, producing a high degree of order through the coherent activity of a large number of molecules.

Arrow of Time

We are all aware of an intuitive "flow" of time from past to future. Not only do we feel this flow of time, but we also see it in the behaviour of objects which change over time. Many objects seem to behave differently in the forward time direction when compared to the backward time direction. For example, we don't see a spilt glass of water jumping up and going back into the glass, we don't see a broken egg reforming itself. These effects all add to the impression that there is some sort of "forward direction" in the time dimension. This directionality is called the Arrow of Time.

However, this Arrow of Time is something of a mystery to physicists because, at the microscopic level, all fundamental physical processes appear to be time-reversible. Prigogine recognised that almost all natural and living systems in our world are far from equilibrium, and that the arrow of time is the tendency of such systems to approach equilibrium, thus reconciling microscopic reversibility and macroscopic irreversibility.