In 1985 Shklovskii 
formulated
the problem of Extraterrestrial Intelligence. He was engaged in this
problem almost all his life. But most surprising is the fact that
having passed the way from the early romanticism of 60's (the artificial
creation of Fobos and Deimos) through the more realistic concept
of the uniqueness of life in the Universe (an absence of space miracles 
),
which engages the west scientists up to now 
, he came to the
conclusion which could be obtained still before the space age and the
programs of searches of extraterrestrial life!
As a matter of fact,
the problem is reduced to the so called Fermi's paradox 
which
in modern language looks as follows (Lipunov,1987):
there are two observational or, if you like, experimental facts:
1) the age of the Universe is 
year, 2) a specific time
t of exponential development for our civilization is of the order
of some tens of years. For the sake of simplicity it san be adopted
years which is obviously an overestimation. A gigantic
dimensionless
number characterizes the growth of a technological
civilization over the time of existence of the Universe:
It is enough to say that the theoretical physics never dealed with
so great dimensionless numbers. For example, the full number of
elementary particles in the Universe looks ridiculously small --
. Fermi 
himself exclaimed: ``If there were anywhere space civilizations, their
spaceships would have been in the solar system long since'' (I don't
guarantee the exactness of the quotation). Naturally, this number is
so gigantic that any unknown intermediate factors are unimportant.
Really, it can be confirmed that probability of absence of
``space miracles'' in our Universe is 
, i.e. is
equal to zero! Nevertheless, nobody has discovered them even after 20
years of searches. On the contrary, a Giant Silence of the Universe
has been revealed. The world without miracles is incredible but it
exists -- that is the paradox.