Quote Originally Posted by Colin Robinson View Post
Not quite sure what you mean by "semantic games"...

The topic I raised in the opening post of this thread was the difference between thinking in terms of "exo-life" or "life in the universe"... Are you saying that this whole topic is just a semantic game?
Frankly, the OP struck me as announcing a seemingly deliberate attempt to skirt around the major elephant in the room, which is that other instances of emerged life, are not simply 'a given'. The word-play even announces to the reader that the whole issue of exo-life existence can be avoided by selective use of language labels. I call that semantics .. pure and simple.

Your OP reference to the Copernican Principle, also sounds the warning bells and a 'call-to-arms' to all casually interested amateur astronomers that a key principle of Cosmology is threatened if Earth-life is inferred to not be ubiquitously distributed. I call this game-play.

Quote Originally Posted by Colin Robinson
It's true that no other life-forms have been observed by us terrestrials. Does that mean we are in a "one-life model observable universe"?
Who knows ?? Who can I consult with, who knows the 'truth' of this matter ? Paul Wally's 'Neutral' Demon, who is so far incapable of distinguishing life from non-life, and life from moons ?
Quote Originally Posted by Colin Robinson
Are "observed" and "observable" the same thing?
Once again ... same answer .. when it comes to life ... who knows ?

Quote Originally Posted by Colin Robinson
Has everything observable on the surface of Mars (for instance) already been observed? If so, why do we bother to send new devices there, such as the Curiosity rover?
Has everything observable on the surface of Earth already been observed ?
No way ! The latest predicted estimate of the number of eukaryote species on Earth is ~8.74 million, and only 1.94 million, (22%), have been described/catalogued to date ... all that after 3.2 to 4.4 million years of human evolutionary existence !
With that information, I'd say the above questions are indicative of yet more moot thinking, carrying no meaning.

In fact, an even bigger number of Earth-life species, all share the same life model ... with none displaying evidence of even one single, separate instance of independent emergence. I'd say that's some pretty good evidence that the emergence and subsequent evolution process, is pretty selective ... in spite of the attempted philosophically motivated co-option of the Copernican Principle into the life topic !