Or what if a drop of water were trickling down the trunk of the tree?
The water in motion would be alive, but the motionless tree trunk would be.
Exosemanticists have their work cut out understanding them, and exopsychologists in figuring out what they're all about.
Relations between humans and Really Aliens are necessarily limited, since we have so little in common with them.
Only rarely will anybody get to know one on a personal level.
TRADE with them is sporadic, and even WARFARE seems less frequent than it used to be in the GOLDEN AGE.
Convergent evolution might well produce a generally humanoid body plan, just as sharks and dolphins have a similar overall configuration.
But Aliens with Forehead Ridges have much more than a general similarity to Earth Humans.
Not only do Aliens with Forehead Ridges mostly look like Earth Humans, they tend to act like Earth Humans as well, or at least one particular (real or speculative) Earth Human culture.
It would be expecting much of anyone to guess that an oyster were alive if he came across one (for the first time) with a closed shell.
Could a glance at a clump of trees in midwinter, when all are standing leafless, easily distinguish those which are alive and will bear leaves in the spring from those which are dead and will not?
Nor is it used for Earth Humans who must register with the immigration service.
In general, Aliens fall into two distinct groups, REALLY ALIENS and ALIENS WITH FOREHEAD RIDGES.1) Really Aliens are truly unearthly. The occasional intelligent bear or radish may also appear, or practically anything else.