What are the characteristics of a living organism? Biologists for generations have been asking this question but none have ever settled on a reasonable definition. Nevertheless two biologists in a book called "The Tree of Knowledge," by Humberto Maturana and Francisco Varela, suggest that the uniqueness of a living organism lies in its ability to organise itself into a self contained unit. The example given is of a chair. For something to be regarded as a chair it must have a flat portion to sit on, legs and a back and this is its organisation. It does not matter whether the chair is made of wood, plastic or that is put together with screws or glue: this is its structure but not its organisation.

They therefore define a living being as a unity in which its components are organized in such a way that they take part in the continual process of recreating that unit. That is to say, a living being is self-organising and self-producing. To convey this idea, Maturana and Varela use the term "autopoesis," derived from the Greek 'auto', meaning self, and 'poesis' meaning producing. The prime example of an autopoetic unity is the single cell. Thus, through organisation of its various components such as mitochondria, enzymes, a living cell is organised as an 'autopoetic' or self-organising unity. The maintenance of autopoesis defines the scope of activity of the cell and as soon as autopoesis breaks down the cell ceases to be living. Multi-cellular organisms are in the same way self-organising and autonomous that is they define their own principles of organisation. And since they are built from autopoetic cells it is this mechanism that defines what life is.

Such an autonomous unity will in the course of its life continually interact with the environment producing a series of mutual series of changes that maintain the integrity of the organism. What is important is that changes that the internal state of the organism goes through are determined only by its need to maintain self organisation. Since life according to the above definition is inherently "autopoetic" the mechanism by which this process is maintained, arguably must be through the agency of a vital force or field that maintains such unity in so complex an environment. Some might argue that it is impossible to remain "autopoetic" without an additional ingredient -a life force or vital-force which owes its ultimate origin to God. This being the ancient doctrine of Vitalism and an important tenet of Homoeopathic Philosophy. (But hard-headed Science has nothing to gain from such romantic revivalism, which A. Whitehead once called " misplaced concreteness".)

DOES VITALISM EXPLAIN ALL?

An argument frequently used in support of vitalism concerns behaviour. It is always been a characteristic of living organisms to behave in a purposeful way, as though they had a goal in mind. This quality is demonstrated even in a unicellular organism such as an ameoba which behaves as though with a certain purpose in mind like gathering food, or moving away from a negative stimulus. An even more interesting case of apparent purpose and coherent activity is the construction of a termite nest. The first stage in this activity is the construction of the base. During this apparently disordered termite behaviour they transport and drop lumps of earth in a random fashion, but in so doing impregnate it with a hormone. This attracts other termites and as they become more numerous in a region the probability of their dropping lumps of earth increases, leading in turn to a still higher concentration of the hormone. In this way pillars are formed and so the termite nest is constructed. Though this behaviour demonstrates that what is seemingly purposeful may not always be the case the search for a life force continues, since the only way the life force manifests itself is through being alive and acting as though we had purpose so the whole teleological argument becomes a charade of words with no further insights into the question. Though Vitalism is an ancient doctrine, its very theme and language fall into the realm of Physics (as the latter is a science concerned with studying the laws of nature) and therefore we turn to it in order to clarify the arguments concerning the vital force.

In the nineteenth century as Sir Isaac Newton charted out the new science of mechanics and tried to bring order into the universe, the science of thermodynamics was also born and became a separate discipline with its own ideas.

In the same way that Newton proposed his laws of mechanics, they proposed a law known as the Second Law of Thermodynamics: The total entropy in a system never decreases. (entropy was an idea introduced to describe disorder). In other words all systems will tend to move towards a state of decay and will eventually run down into a state of disorder and thermodynamic equilibrium. If you heat a liquid it will alter its structure and then eventually settle down and nothing more will happen. To change it or reverse the situation one would have to expend more energy and this would produce even more entropy. We might suppose that the cosmos has a finite stock of order and is changing irreversibly towards disorder. We see the second law of thermodynamics at work everywhere in the universe. For example the sun cannot continue burning ad infinitum but must run down soon or later. This process of irreversible change will lead eventually the "heat death" of the entire universe.

Paradoxically living organisms contradict the Second Law of Thermodynamics. As the presence of life is a classic example of ever increasing and self-maintaining order evolving to ever more complex living systems. Is this a case for the divine agent to be at work through a vital force which would animates and maintains order out of disorder ?

On closer inspection, living organisms do not contradict the Second law of Thermodynamics, since the latter applies only to total systems and a living organism is an interactive open system and can only survive by exchanging energy with the environment. If one looks at the organism and the environment as a total system then the order maintained through the life form is paid for by increasing entropy in the whole environment.

Nevertheless our original definition of life does require that its integrity as an "autopoetic" form is not breached and this constant state of orderliness (or negative entropy) is the crucial ingredient for maintaining life as it is.

Erwin Schrodinger in his book What is Life? expresses it thus

"An organism has an astonishing gift of concentrating a 'stream of order on itself and thus escaping decay into atomic chaos-of 'drinking orderliness' from a suitable environment."

So to sum up, the essential characteristics of life that we can establish from a study of the Second Law of Thermodynamics is that life is a state of Negative Entropy. But so far this does not bring us any closer to establishing whether a vital force is necessary in establishing life forms.

LEVELS OF CONFUSION

Another mistake made in invoking the life force model is in overlooking what happens when individual components of a system come together to create further levels of complexity that were not originally there. In the case of a jigsaw puzzle it can only be solved by putting it back together and creating a synthetic whole. In other words there are systems which can only be perceived at a higher level so the whole becomes greater than its individual parts. This particular idea is sometimes referred as Holism in contradistinction to Reductionism which has been the main thrust of western scientific thinking for the past three centuries.

What is important about the Holistic view is that qualities seem to emerge when viewing structures from a higher perspective as in the example of a novel, at one level it can be viewed as a collection of words but from a different perspective it can become the plot of a very exciting novel.

A far more interesting distinction is at the computer level. A modem computer consists of two levels of operations one is the hardware level consisting of electrical circuitry and the other level is the software which might consist of some complex program describing something. Both operate in a computer but at different conceptual levels. Further more the hardware operates when the electrical current is turned on but none would credit the current with vitality it is just a force and yet the computer might be accessing some incredibly difficult problems at the software level. This again opens up another can of worms since it brings in to focus the question of artificial intelligence and again asks the difficult question what is life since the computer does remain a self-organising unity and can therefore be regarded as possibly alive. What is important in this case is that electricity has not suddenly taken on the attributes of a vital force and yet it is a force, which animates a system.

This state of self-organisation remains one of the arguments for giving computers and their mobile prodigies-robots some sense of animation .It is a controversial and ongoing debate that is in no way silent as computers get more and more complex and are able to perform in ways close to humankind. This controversy started in the early eighteenth century when some remarkable creatures were produced by French clockmakers such as Vaucanson and Droz. For example J. Vaucanson built a duck that flapped its wings, pecked at a foot, drank water, and evacuated a fetid pellet after passing through a digestive system. This remarkable fowl directly posed the question of how, and to what degree, they differed from the human, a question that has haunted us ever since. Moreover much to his credit, Vaucanson resisted the conclusion drawn for him by La Mettrie , contemporary of Descartes, who in his famous book published in 1747 L'Homme- machine, proposed his theory that the body was a machine with self-winding properties. He invoked the duck's intricate digestive system as evidence that complexity was no argument against considering the human organism solely a machine. Even more controversial is a book recently published by Francis Crick, Nobel Laureate for unravelling the DNA coil, called " The Astonishing Hypothesis; The Scientific Search for the Soul". Crick believes that conscious awareness in higher animals and humans has something to do with the rate at which brain cells oscillate. When, for instance, a cat sees a mouse, its brain cells oscillate at the rate of 40 Hertz a second. With recent developments in neuroscience Crick claims that by experiments and imaginative thinking it should bi possible to understand the workings of the brain and therefore comprehend the nature of the soul. Though the book is certainly astonishing in the extreme, it highlights the central question of a vital force and the complexities of trying to define consciousness.

Nevertheless what is important to take into account however, is that life is a holistic phenomenon, from this books point of view and one can comfortably abandon the old idea of a life force since this is based on a confusion of levels. As the idea of a magical quality bringing alive inanimate matter is as misguided as the example above of giving the electrical current extra powers for bringing the computer alive or denying the brain its own ability to create consciousness??

Once one has come to accept that a holistic perspective removes the need for a life force that permeates each cell one would hope that physics might be able to offer some alternative view or description of life.

Yet again we return to the question is it possible to deduce life from a set of collective phenomena? It is still obvious that we have two sorts of matter; living and non-living. Yet they behave in totally different ways however one going towards more order, and the other behaving according the Second Law of Thermodynamics and going towards a more disordered state. And yet they both are made of the same components.