It's nice that they made the Na'vi a certain amount bigger than humans
Yes, size is an important factor- usually every creature magically has the same size ranges as us- them as well as
their children! Varying that is a start
That aspect has never really bothered me too much. It is entirely possible that particular attributes are better suited to more intelligent life. It makes sense that an advanced organism would have many of the same features we do and would have at one point needed to overcome the same obstacles we did.
That's not actually plausible though if you're thinking about evolution- which is inherited "change" in response to numerous factors alone and in combination- sex, environment, climate, disease, geography, etc.
Evolution isn't a process leading "too" anything, there are no predetermined ends or likely paths, it's just change itself. Life on earth seems to follow related paths only because we are actually
related- Lizards, birds, fish, humans etc all share the same type of skeletons with the same sorts of bones. Even the feather patterns on a bird's wing are similar to the hair patterns on a human arm. And even more varied life like squids or slugs have deeper similarities.
And as far as "intelligence" goes, that isn't really dependent on body shape. We know that Ravens display advanced problem solving abilities and tool usage, even exceeding that of the great apes and the fabled dolphin. Even creatures like octopus have surprising abilities in that regard! :)
Going back to evolution- if certain environmental factors had been different in the earliest days, then all life on this planet would've had a vastly different appearance than it does now. Even bilateral symmetry is an evolutionary artefact that animal
life has just happened to retain from those early origins. It could have been very
Jeebus, this is an essay!!!!!!!!
Suffice to say that it's not impossible that life elsewhere could look like us only
because the universe is almost infinite, but it is extremely
That said- SciFi with totally
alien unhuman creatures probably wouldn't be nearly as interesting or fun.
The use of the word unobtainium seems far less likely to me. It defies all naming conventions for elements and compounds. It would be far more likely to see it called anephictium or something like that, rather than unobtainium. Even so, though, the name isn't an accurate descriptor for the material, so the name really doesn't make any sense.
What about Thorium? Named after the Norse god for the hell of it... Or Californium or Einsteinium? Element and compound naming doesn't actually follow any proper conventions- you discover it, you name it, for your own reasons. The scientific community is traditionally pretty open to that.