Are we able to adequetly theorize the significance of the opposable thumb among intelligent life elsewhere in the cosmos? Is it possible for "aliens" (and I will use the term for convenience sake) to not have an opposable thumb seeing as how they are able to trek the universe? In other wrods, how significant is the opposable thumb simply as a universal concept? And if not the opposable thumb, have we been able to suppose what else could possibly be more advantageous?
The opposable thumb stands in contrast to the animal paw which is not as capable of working with the prototype tools of the "termite extractor" (stick) or the "prototype hammer" or the "prototype boomerang" (both are "rocks" to you and I). From prototype tools to primitive tools, requires the intelligence to plan a particular use and craft the tool to do the job. Modern tools require a background in logic and applied physics and meaningful abstract communication for design and in most cases use.
One can imagine octopi with human intelligence. They have the ability to do some of the tasks that humans require their thumbs to do.
http://news.bbc.co.uk/2/hi/europe/2796607.stm
But the fact that water is 800 times denser than air limits their ability to generalize the concept of a projectile weapon (rock). And the denser water is what renders the tentacle with its lack of internal skeleton as competitive.
But I can envision workable alternatives to the opposable thumb for technological development. Thus, I don't think it is required.
As for intelligent life itself, if you are willing to lower the bar, Earth has many examples of intelligent (goal seeking, problem solving) life.
One can imagine octopi with human intelligence. They have the ability to do some of the tasks that humans require their thumbs to do.
http://news.bbc.co.uk/2/hi/europe/2796607.stm
But the fact that water is 800 times denser than air limits their ability to generalize the concept of a projectile weapon (rock). And the denser water is what renders the tentacle with its lack of internal skeleton as competitive.
But I can envision workable alternatives to the opposable thumb for technological development. Thus, I don't think it is required.
As for intelligent life itself, if you are willing to lower the bar, Earth has many examples of intelligent (goal seeking, problem solving) life.
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Are we able to adequately theorize the significance of the opposable thumb among intelligent life elsewhere in the cosmos?
No, we only know of Earth life, so we have no real objective way of rating the opposable thumb's significance in the overall universe. At this point, all theories will remain biased toward life on Earth and human intelligence/technology.
My own opinion is that it is only one of many options and that a humanoid bipedal body plan is also just one of many options for intelligent life.
The person who best hypothesized possible evolutionary developments was Gene Bylinsky who used the award winning illustrator Wayne McLoughlin in his book, "Life in Darwin's Universe: Evolution and the Cosmos." He wrote, "Given the many possibilities of evolution, it's not inconceivable that under certain circumstances, a marsupial could evolve into a highly intelligent biped." The accompanying illustration shows an upright humanoid with a little "joey" peering at you from its pouch! 
Had placental mammals faced an extinction event, this could have been "The Planet of the Marsupials!" From, "Why not unicorns?"
by photojack, Posted on: May 26 2007, 03:09 AM.
The same bone structure that brought us porpoise flippers, bat wings, three-toed AND four-toes sloths, also brought prosimians and humans an opposable thumb. Visualize if you will, a large-brained, highly intelligent octopus-like chordate with eight arms all equipped with opposable thumbs! I seem to remember a cartoon from the past with a "multi-tasking" octopus reading with one arm, attending to food cooking on a stove with another, disciplining a wayward child with another, and some other task with a fourth one, while standing on the other four like a quadruped! Anyone remember that? Have a source? Is it on "You Tube" now?
Had placental mammals faced an extinction event, this could have been "The Planet of the Marsupials!" From, "Why not unicorns?" by photojack, Posted on: May 26 2007, 03:09 AM.
The same bone structure that brought us porpoise flippers, bat wings, three-toed AND four-toes sloths, also brought prosimians and humans an opposable thumb. Visualize if you will, a large-brained, highly intelligent octopus-like chordate with eight arms all equipped with opposable thumbs! I seem to remember a cartoon from the past with a "multi-tasking" octopus reading with one arm, attending to food cooking on a stove with another, disciplining a wayward child with another, and some other task with a fourth one, while standing on the other four like a quadruped! Anyone remember that? Have a source? Is it on "You Tube" now?