Chapter II

 

 A  probabilistic model of universe

 

French version

 

 

1) The suggested model is a model of rigorously scientific and non-speculative or metaphysical nature.  It is thus subjected to the criterion of falsifiability of Popper and the einsteinian requirement of observable facts ( the bases of the theory of General Relativity 1916 ).  

 

2) Determinism :  The most completed expression of determinism is the conception of Laplace (1814).  According to this conception, it would be enough to know completely the state of the universe at a given time so that the totality of the last states is known and that the totality of the future states becomes prédictible.  This theoretical conception is practically unobservable and unrealizable.  In addition, it constitutes an exponential and arbitrary extrapolation, perfectly   anthropocentric of  causality.  It is to affirm, for example, that the great biological mass extinctions  on the earth were predictable  before even as our galaxy, the Milky Way, was born, there is several billion years ago.  This assertion, of laplacian meaning, does not have any scientific base and is in formal contradiction with the observations and realities of nature. 

 

Determinism rests on a wrongly extensive conception of causality.  The phenomena of nature occur when certain physical conditions are joined together.  The nuclear reactions, inside the stars, start only when, for example,  hydrogen is available and a minimal threshold of temperature is reached, by the gravitational contraction.  The star must also have a certain mass.  The life is conceived, currently, as being able to exist only starting from cells, prokaryotes or eukaryotes.  What is said to be the causes of a phenomenon are, ultimately,only certain dominating conditions (mass of star, presence of hydrogen, temperature, cellular organization, etc...), " all equal things in addition ". 

 

The laws of science establish bonds between the phenomena.  They indicate that, when certain conditions are met, certain phenomena necessarily occur or occur with a great probability (examples above, presence of masses causing a newtonian gravitational attraction or an Einsteinian curve of the space-time, " cause " starting of the nuclear reactions inside a star, presence of oxygen at the  Precambrian " cause " of appearance of aerobic organims, etc...).

 

Thus one can say that the concept of causality, in the phenomena, actually only  represent the dominating influence of certain conditions, called causes (temperature, cells, masses, oxygen, etc...) among a multitude of other conditions (minimal mass of a star, cellular genes, density of matter, presence or not of a cellular core, etc...).  The laws indicate the way in which the dominating influence, i.e. probabilistic, of these conditions appears.

 

3) The probabilistic model proposes to reject the concept of determinism or causality, an abusive and inadequate concept, as we have just shown it, to the profit of the concept of chance, defined as  a concept of probability.  The concept of determinism or causality is an antiscientific concept which, moreover, is made of, historically,  a true anthropocentric or religious background ( first cause, final cause, first engine, origin, creation, etc...). 

 

Thus is the universe the only fruit of the chance?   

 

The probabilistic model of the universe proposes this conception. 

 

4) What is chance ? 

 

Chance is generally conceived like the absence of any law, chaos, the absolute contingency, the meeting of two independent causal series (Cournot 1843) and, finally, the unpredictability. 

 

Actually, the true nature of chance is the negation of  determinism or causality, an absolute concept, to  the profit of the relative concept of probability.  In a certain state of the universe, characterized by many conditions, phenomena occur when certain conditions are present (minimal temperature for the release of the nuclear reactions within a star, need for present oxygen for the operation of the eucaryotes cells of the metazoans ).  These conditions constitute dominating but non-single factors of probability, interpreted, within the deterministic framework, as factors of causality.  

 

The concept of probability is defined sometimes like subjective sometimes like objective.  We will retain here only the theory of probabilities as a mathematical model of the chances of production of an " event " and its application, the law of the large numbers or law of Jacques Bernoulli (1680).  Summarily translated, this law expresses that the events, of which the probabilities or the chances are very weak, occur rarely or never and , vice versa, those of which the probabilities or the chances are high (example of the typist monkeys of Emile Borel, Boursin 1986) occur.  The concept of probabilities, introduced by Blaise Pascal (1654), establishes the ratio of the number of favourable outcomes  to the number of possible cases.  If one takes the example of a coin thrown in the air, the chances of seeing  the side pile appear are 1/2.  In the case of a dice, the probabilities of seeing   each face appear  are 1/6.  The physical or chemical constitution of the coin or the dice, the height, the speed, the duration of the jet, etc..., are factors or conditions which play a negligible role in the result of the jet.  The probabilities thus arises, among a whole of conditions, like a dominating but non-single factor.  The probabilities orders and simplifies the " events ":  the result of the throwings, according to their mathematical chances, in fact 1/2 or 1/6.

 

Ultimately, the probability selects, among the many parameters which condition the production of an " event " ( in the above mentioned example, the structure, the chemical composition, the kinetic energy of the object, etc...), only one parameter, the number of faces of the object (2 or 6), which simplifies the phenomenon and determines the mathematical chances to which the law of Bernoulli applies.  The mathematical developments of the theory of probabilities are complex but it is not the place here to expose the details of them. 

 

The application of the law of the large numbers is largely justified, knowing that all the phenomena of nature utilize gigantic numbers :  approximately 100 billion galaxies in the observable universe, average mass of a galaxy approximately 10^42 kg, average number of stars in a galaxy 100-300 billion, number of Avogadro Na = 6,022.10^23 mol-1,  number of neurons in a human brain, approximately 100 billion, etc… 

 

The intervention of considerable numbers in phenomena, physical or biological, justifies the use of mathematics in the development of knowledge, just as the concept of space generated geometry.  Mathematics, resulting from the everyday life of the human beings, developed and got free of their empirical origin.  They can thus work out imaginary concepts  ( imaginary numbers, imaginary time, etc…).  The mathematical truth does not have any need for the physical validity.  Its only validity is its coherence with its premises.  Thus, the not-Euclidean geometries have the same validity as the Euclidean geometry.  Mathematics constitute a powerful tool of research and theorization of physics as it, for example, the evolution of the theory of the gravitation shows it.  It is at the same time their force and their weakness.  Their force, because they allow the development and the verification of sophisticated physical theories (physical statistics, thermodynamics, gravitation, etc…).  Their weakness, because their coherence, the only criterion of their validity, is unable to validate a physical theory without experimental or observational verification.  Thus, the concepts of imaginary or reversible time, parallel universes, holes of worm, singularities, instantons, etc…;  fashionable  in contemporary astrophysics and cosmology can be mathematically coherent but, physically, highly speculative and quasi-unverifiable in experiments. 

 

The force and the weakness of mathematics apply without restriction on the data-processing models. 

 

The role of the probability that we propose in our model is apparent in many fields, as we enumerate it in the following chapter.  Being given the complexity of the phenomena of the universe and the very different scales where they are held, the presence of the probability is not always obvious, although it is underlying.  The properties of an atom, those of an eukaryote cell or a star seem to concern apparently very different laws, regarding the distance of their respective dimensional scale (approximately 10^-15 m;  10^ - 5 m;  7 10^8 m).  Actually, these various phenomena are the result of the theory of probabilities applied to different conditions, as the  determinism allotted it to causality.  According to the probabilistic model, the phenomena of the universe, as well physical as biological, are the product of the chance, defined as  the field of the theory of probabilities and the law of the large numbers.  The theory of probabilities is the fundamental law of the phenomena of the universe.  This law applies to the ultimate elements of  matter-energy (particles or superstrings ) which exist and generate all the diversity of the phenomena, from the microscopic scale to the  macroscopic scale, by the play of the probabilities and the law of the large numbers. Chance is the single, visible or underlying manufacturer, of the multiple and varied phenomena of universe.  It replaces the concepts of causality and of determinism. The natural laws are the expression of the complex systems where the probability developed.  The indeterminism of nature, far from being a factor of chaos or disorder, as it is generally believed, is, in last analysis, a factor of order and organization of the phenomena, on every scale.  The theory of probabilities allows, by its application, a predictability of the phenomena. 

 

Applied to the problem of biology, the theory of probabilities singularly clarifies the correlations between the various factors of the environment and their organic correspondence (biochemistry, morphology, sensory tissues, etc...).  According to the theory of probabilities, the most probable " events " occur.  We thus proposed, in accordance with the preceding observations, that the current constitution of the living organisms is the result of the most probable interaction, statistically, between the stimuli of the environment and the specific properties (biochemical, genetic, anatomical, behavioural, etc...) of the living matter.  The environment having evolved, in its complexity, since the Precambrian one, the evolution of the living organisms would be also the result of the most probable interaction (see:  A probabilistic model of the biological evolution:  < http://site.voila.fr/dinosaurs >. 

 

The probabilistic model proposes that the concepts and the physical or biological theories of the universe (gravitation, Newtonian or Einsteinian, quantum mechanics, superstrings, cosmology, etc..., constitution and evolution of the organisms, etc...) are the phenomenological expression of the underlying probabilistic structure of the universe. 

 

5) To know or to understand the universe ?

 

In contemporary sciences, the scientists seek the knowledge of the phenomena which they study, i.e. their structures and their operations.  Wether they are stars, galaxies, genomes, quarks or strings.  The ultimate goal of science is to gather the whole of the phenomena in unified theories (example the Theory of All - Theory of Everything in  physics ).  Actually, it is a question of knowing, not of understanding the universe.  More prosaically, the scientists seek it how, not it why phenomena work.  The reason of the phenomena (microscopic or macroscopic, physical or biological) does not seem to belong to  their field.  Metaphysics and religious myths bring here their obscurantist and dogmatic phantasms.

 

 

Next : III Proposals of the probabilistic model of universe

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