posted on Apr, 6 2009 @ 01:00 PM
I read a book released by SETI when I was a kid. It had articles by Shostak and various scientists and philosophers. In amongst these chapters were
short stories by Bova, Asimov and Clarke. A chapter described how dolphins have a similar language cortex (sylian?) to us. It fairly caught my
imagination.
One chapter reasoned that the most likely form ETs would take would be upright, two legs, two arms, opposable thumbs and binocular stereo vision.
Opposable thumbs would be required for the manipulation of tools. Stereo vision to focus on intricate manipulation of material objects. It reasoned
that nature is efficient. If we had three arms they would be useful, but two arms serves our needs adequately. One arm would fail through natural
selection. The same sort of logic applies to two legs. The ability to remain upright whilst in motion would offer advantages towards survival when
predators are a factor. Rodents can hold and manipulate objects (squirrel eating a nut), but they can't hold an object when moving.
I don't know how well those ideas would stand up to modern scrutiny, but they seemed fairly reasonable.