What is an intelligence or an intelligent life? What is the purpose of its appearance among other creatures of nature? We shall not discuss in detail these questions. We shall restrict ourselves with to following simple thesis: an intelligent life tries to understand and to explain phenomena which happen around. It is important that interest and curiosly arising in this process are highly unstable. An interest to the phenomenon which has been understood vanishes practically instantly.When we discover a new law of nature we begin at once to look for some new phenomena which are not subjected to this low. There are no such practical applications of old laws which would be more interesting than searching new ones. Various particular cases, new regimes, original approaches etc. being attractive as they could, all this is a pale shade of a real process of cognition. An intelligence is stunted without principally new, unexplained phenomena.
It is possible to perish from an atomic or biological bomb. But all this are childish toys compared with what could be invented by a civilization outstripping us, say, by some 200 years. Even nowadays in the limits of natural laws discovered by us, one can imagine so powerful a weapon which, once applied, could evoke consequences noticeable in the whole Galaxy. Such a ``brother-murdering'' war would be quite a space miracle. But miracles do not exist!
Forces which prevent the development of intelligence must be of quite other nature. And they, certainly, must be of universal character which doesn't depend on any specific conditions.
Before than we shall begining to describe a possible reason leading to the destruction of an intelligence (its natural destruction), let us consider the following problem: why a human being, during the shortest time intervals (on a cosmological time-scale), has become successful in understanding the laws of nature acting in a whole observable Universe? Some two or three thousand years was enough to reach quantum mechanics and General Theory of relativity. How has a man whose every-day experience is limited by commonplace scales measured by metres, by velocities of some tens of million times smaller then the velocity of light, and by insignificantly small gravitational field, -- how has this weak being penetrated, without leaving a house, into huge space of the Universe and into the deepness of infinitely small elementary particles?
The ancient philosophers described the cognition process in the following manner. Let us imagine an infinite plane. A circle on the plane symbolizes the knowledge we have already attained. In the cognition process the circle increases and absorbs the previous knowledge., but also a boundary with unknown increases. Cognition yields more and more questions. The process is infinite.
This point of view is old as the world. Is not this a too primitive generalization of our quickly passing experience? May an infinitely complicated object be indeed so simple? Rather no then yes. ``A complexity'' is, first of all, a qualitative characteristic, not quantitative one. An infinitely complicated object must consist of infinitely complicated, qualitatively different parts which are not under an obligation to be compatible. The world or, more correctly, a system of knowledge about the world is not a ``matrioshka''. If we have understood a part of this non-simple object we cannot be sure that our knowledge will enter into the next system of knowledge like a small ``matrioshka'' enters into a big one.
A process of cognition rather must be a strongly nonlinear one. An extreme, but not particular, case could be a so strong non linearity that a comprehension of any part would be impossible without realization of the full picture. In other words, an infinitely complicated object cannot be comprehended in principle. An intelligence could not arise in an infinitely complicated universe!
A negative thesis expressed above as to the incompatibility of subsequently comprehensible parts is in contradiction with all our experience. All our experience cries that our world is something like ``matrioshka''. For example, the Newton's mechanics became a part of the special theory of relativity by Einstein which, in turn, became a part of the General Theory of Relativity. This is Bohr's compatibility principle.
How can we take away the obvious contradiction? There are two possibilities: whether our imagination of infinitely complicated object is incorrect or the surrounding world is not infinitely complicated. One can choose a correct answer only if he is based on observational facts...
Let us recollect: an intelligence without food perishes. And everything comes into place. An experimentally proved absence of supercivilizations argues for the fact that our Universe is too simple for intelligence. Quickly (in some thousand years) an intelligent life comprehends all natural laws, exhausts all possibilities of its applications and perishes. This is a paradox but this is a fact: intelligence arises and perishes due to the same reason, that is, a simple structure of our world.