




        
            Our relation with the universe could be summerized in these
       words:
            We get some perceptions from the universe, and they are not
       random, there are some regularities. Mathematically, this means
       that our perceptions could be described by an expression smaller
       than the one describing them in the form in which they appear to
       us (in the same way that, for example, the expression:
       "ABCABCABCABCABCABCABCABCABCABC" which contains 30 characters
       can be described by "ABC repeated 10 times" which contains only
       21). This constatation allows us to suppose that our perception is
       the unfolding of a smaller "germ", which we could call the
       reality, and to build some mathematical models of this reality.
       But these models are not the reality itself, they are only mental
       constructions in our minds.
            Several models can yeald to identical perceptions. In this
       case, it makes no sense to ask which is the real one, because they
       are all real since all are concordant with our perception. For
       example, it does not mean anything to ask if there really exist
       other worlds if these worlds are completely inaccessible to us.
       From this point of view we can also say, for example, that a
       theory saying that the universe has been created yesterday, or one
       second ago, with coherent memories put in our brains giving us the
       impression that we exist since several years, is perfectely real
       because if it was true, we would perceive exactly what we actually
       perceive.
            But, depending on the goal we want to reach by constructing a
       model of the reality, we might prefer one model between several
       which accord with our perceptions.
            I think that almost every physician agrees with the fact that
       the better model is the simplest one, but the divergence concerns
       the precise definition of the simplicity of a model. IMHO, the
       most important is not the complexity of the concepts used by the
       model, nor the fact that it is far from our immediate perception.
       I think that a good measurement of the complexity of a model is
       the number of characters of a text describing it in an adequate
       language (this point should be precized...).
            Has anyone another idea for defining the complexity of a
       model?
            With this definition, the many worlds theory seems to me to
       be simpler, because the fact that there are many worlds does not
       add complexity to the theory if the same physical laws apply to
       all of them, and we avoid the problem of the collapse of the wave
       function.
            I think that in fact the real reason that makes the many
       worlds theory difficult to admit is that we like to feel ourselves
       at the center of the world. It has been difficult to admit we live
       on one planet turning around one star lost among the myriads of
       other stars of the universes. Many scientists still does not admit
       easily the fact that our civilization could be only one among
       millions others, perhaps more advanced... and of course it is much
       more difficult to admit that our world could be only one among an
       infinity of possible worlds.
            However, when I take a decision, I often imagine the
       different worlds resulting from this decision, their future
       evolution, and I ask myself which of them I prefer to explore...
            One could go much further with this idea...
            How could we explain the fact that the physical laws are just
       the right to allow the development of complex life ? (the











       anthropic principle...) Simply because we are here to talk about
       that! There could exist many other universes whose physical laws
       does not permit the apparition of complex forms of life, but in
       these universesw there would be noone to talk about these
       questions...
            This yields to a very simple Theory of Everything:
            "Each mathematical model of a possible universe generates a
       universe."
            This theory, whose complexity is only 67, explains completely
       our universe and all possible universes. Who propose better ?
            It also answers to the most fundamental metaphysical
       interrogation:
            "Why is there something rather nothing ?"
            Even if there were nothing, mathematics would exist because
       it can be defined as the studying of the structure of nothing. So
       mathematical models would exist, then universes would exist.
            Is there any place for the spirit, consciousness and free
       will in all of this ?
            I think it could appear in universes generated not by a
       finite mathematical model, but by an infinite one, which could be
       defined as the limit of an infinite sequence of finite models,
       which approximate the reality more and more precisely but never
       reach it. The spirit might be the part of the reality which the
       model does not describe, a part getting smaller and smaller, but
       never empty, when the model gets more and more precize.
        
                      "What a small computer can do with a big program,
                       a big computer can do it with a small program.
                       Hence the logical conclusion that an infinitely
                       big program can run alone, i.e. without help of
                       any computer."
        
                                          Stanislas Lem,
                                          "Professor A. Donda".
        
        
            
        
        


























