The possibility of extraterrestrial life has caused some 
ideological embarrassment in the Soviet Union. There used to be, in Alma 
Ata (Almaty), Kazakhstan, an Institute of Astrobotany, some of whose 
members argued that the existence of extraterrestrial life was required 
by dialectical materialism, and implied strongly that the absence of life 
on Mars, and even on Jupiter, would be a clear disproof of the 
philosophical basis of Communism. This dangerous situation prompted an 
article in the Sept-Oct 1958 issue of the Soviet astronomical journal 
_Astronomicheskii Zhurnal_, called "Concerning the 'Philosophical 
Foundation' of One Question", by I.G. Perel', in which Perel' points out 
that both the materialist and the idealist philosophical schools seem to 
strongly support the likelihood of extraterrestrial life. He argues that 
dialectical materialism is a method, not a body of knowledge, as 
Shklovsky did elsewhere in _ILitU_; and in particular, that even if Mars 
or Jupiter is lifeless, dialectical materialism is not disproved. This 
debate has been echoed by other discussions in the United States, which, 
while on a different ideological basis, turn out to have very similar 
content.

Carl Sagan, preface of _Intelligent Life in the Universe_, coauthored 
with Iosif S. Shklovsky