Most scientific discussions of alien life refer to the existence (or otherwise) of extraterrestrial intelligence; for example, the I in SETI refers to intelligence. This is necessary because radio contact with aliens is possible only if the aliens are intelligent enough to possess the necessary technology. Philosophically, however, it is the existence of alien consciousness (or cognition) that is significant. The discovery of extraterrestrial conscious beings that did not qualify for the human definition of "intelligent" would still be a momentous event. After all, psychologists are divided about how to define and measure human intelligence anyway.
Conversely, we can imagine discovering intelligence without consciousness. While the possibility of conscious computers remains an open question, the drive to produce so-called intelligent computers on Earth proceeds apace. It is entirely likely that in a few decades we may possess machines that can fairly be described as intelligent in their