Feh! To little gray (or green) "men".
Frankly I just can't buy into the idea that extraterrestrial intelligence has much of a chance at ALL of looking even vaguely "human".
When you consider the stunning variety of shape and form life takes on our world, a world likely to wind up being one of millions to evolve intelligent life, then imo, applying the principle of mediocrity would argue strongly AGAINST the idea that E.T.'s are going to be found to resemble us at all.
The fact that "bipedal critters work here", imo, is meaningless sophistry. "Bipedal critters" are by absolutely NO means the only critters to have "worked" on our world. In fact if you take into account all of the varying forms life has taken on our world that have lasted, we and our bipedal distant cousins, form a very distinct minority of that particular group, terapods are an even smaller sub-set of that group, and primates account for SUCH a small part of the overall picture of "life on Earth" as to render the idea of intelligent life from another world looking like us to border on the ridiculous imo.
TOO many coincidences have to add up just right for that to happen.
The gravity of the planet has to be high enough to offer vertebrates a survival advantage.
It has to be high enough to allow for a bipedal gate to be an efficient mode of locomotion.
But low enough to allow whatever passes for "bones" on that world to support the weight of the life-forms that evolve them.
Suppose an intelligent life-form were to evolve on a world with one sixth Earth's gravity?
In that case a multi-armed uniped might wind up being a more efficient choice of form. Two legs didn't appear to me to be much of an advantage to our species the very first time we "walked", or more accurately hopped around in an ungainly and uniquely silly looking fashion, on our own moon.
Suppose a world like that were dominated by low hanging trees (which for all we know may not even qualify as anything that could be considered vegetation I should add), what possible survival advantage would two legs, two arms, and a head offer?
It seems to me that something vaguely similar to an air breathing version of an octopus might be able to move through such an environment like a puff of wind blown smoke, while it would be the relatively ungainly, and all too easy to catch bipeds that quickly go the way of the Do Do long before evolving intelligence.
And that's just considering how relatively tiny differences in gravity might change things. Or not.
If you look at the evolution of life on THIS world, as being like a game of pool, with lots of games of pool being played on lots of different worlds, all following the same basic "rules", then the fact that "bipeds" wound up developing intelligence on our world may well have no more meaning at all than the fact that on OUR world, in our PARTICULAR game of pool, the 2 ball was sunk first, the 9 ball second, the 11 ball next, and the 5 ball after that, etc., leading to bipeds being the ones that developed intelligence. But what are the chances of exactly the same sequence of events being duplicated exactly in any of the other games being played?
Not all that good imo.
The way I see it, each game on each world, is MUCH more likely to lead to VERY different outcomes when it comes to the specifics of how many fingers, how many eyes, radial symmetry or axial, or even whether or not it's possible for them to be plagued by pimples during adolescence (assuming that something even vaguely similar to "adolescence" occurs in THEIR life cycle, in THEIR particular game).
To become tool makers all you need is a big enough, and complex enough brain, and the means of articulating the tools developed.
"Hands" are ONE very nice and elegant solution, but they're not the ONLY solution.
The classic "Bug eyed aliens with tentacles" we commonly associate with the "monsters" of pulp Sci-Fi running around accosting scantily clad female hominids, could develop practical tools every bit as well as those of us with a single pair of "hands" don't you think?
The tools would be different, cumbersome for US to use perhaps, but what would lead anyone to think that four fingers and an opposable thumb is the ONLY way for someone to develop the ability to "skin a cat"?
I DON'T BUY IT.
In fact, one of the things that's always made me VERY suspicious about UFO stories of people being kidnapped by "little gray men" is the idea that the nefarious villains of nearly all of those stories look so "human".
Fairies look like humans with wings added.
Titans and Olympians were almost always either humanoid in appearance, or half human, half animal.
So were many of the Egyptian gods.
Valkyries, lepricons, elves, Orcs, and vampires, Vulcans and even "E.T. the extraterrestrial", all look to me at least as suspiciously close genetic relatives of our own species.
WHY IS THAT?
I think that it's just an aspect of human nature to see a reflection of ourselves in our own dreams and imaginings of "what might be". It's comforting in it's familiarity, but imo has no basis in what could be regarded as scientific thought.
It's exceptionally tempting to manufacture reasons and reasoning that predicts that intelligent life on another world will be much like our own, with little more than "minor changes in skull structure depending on the kind of conditions they live in".
I think that if and when "first contact" occurs we're likely to be STUNNED by how different even the nearest of our neighbors turn out to be, and that it's likely to be one hell of an object lesson in just how limited our imaginations are in comparison to what nature is able to come up with.
Even “Bug eyed aliens with tentacles” are likely to wind up seeming comparatively familiar compared to what we run into if and when we meet “people” from another world.
