[Ehkzu]

This being a discussion of evolution in a science fiction forum, I'd like to propose something germane to that intersection:

While creationists don't understand evolution at all, the average sci fi reader and writer does...but doesn't understand how powerful convergence is in evolution.

Thus it's likely that intelligent aliens on other worlds look and act a lot like us. But sci fi writers/readers reject this proposition out of hand. We don't WANT this to be true. We want the Star Wars cantina.

Now the problem is that this point will never be proven. Up through the 1950s sci fi was full of stories about the swamps of Venus and the deserts of Mars and even intelligent aliens on worlds like Jupiter. Now we know better, and that's all gone away. Ditto all the spaceships that weren't computerized, that lacked solid state displays and whatnot.

But we'll never get out of this solar system (hope I'm wrong, but I'm not), and they'll never get here (again, hope I'm wrong, but I'm not). So John Q Sci Fi reader/writer may well continue to hold ideas about intelligent life elsewhere that go against what current biology tells us.

Let me add that it's not like I haven't seen some wild alternate life forms. I'm a scuba diver currently planning my 5th dive trip to Indonesia, and the stuff I've seen there makes my head spin just thinking about it.

But none of them are advanced technology using critters.

And I put it to you that that requires a terrestrial bipedal hominid. We have an evolutionary model for that. We don't have one for any other path, and I've never read a sci fi novel or seen a sci fi movie that provided a compelling one.

I'm also invoking what scientists call the Principle of Mediocrity--that, in general, whatever is, is average.

No Star Wars cantina. Deal with it.