ABSTRACT
This chapter is concerned with three notions that are frequently advanced by search for extraterrestrial intelligence (SETI) proponents. The first notion is that once life appears on a planet, intelligent life is also very likely. The second is that once intelligence appears on a planet, science itself is likely. The third is that all scientific civilizations have something in common and thus the basis for the beginning of communication between them. Defenders of the SETI program often assume that advanced sciences and technologies must exhibit a high degree of convergence. The grounds for this assumption are presumably, that as science grows in scope, the brains that produce that science must reckon with all-pervasive features of the universe. A highly complex brain can deal with the environment in a very flexible and indirect manner. Moreover, it is not one brain but an ensemble of brains in very complex social relations that deal with the universe through science and technology.
