Instead of a radio signal from a extraterestrial intelligence it would be a LOT damned scarier to find evidence of active stellar engineering going on.....
How do you fight against THAT?
They’d be so busy trying to fill up just one such structure (after taking who knows how much time to actually build it) with themselves, it’s not likely to become a problem. Also, if they had interstellar capability, they wouldn’t need to build such a structure. IOW, whether such structures exist or not seems like a good test for two mutually exclusive questions.
1) if there’s no evidence of any of these structures, either A) there’s might be no intelligent life to build it, or B) the intelligent life hasn’t had time to build it, or C) the intelligent life hasn’t had need to build it, or D) the intelligent life has interstellar capability.
Okay, that’s one question. I’m sure there are more possible options.
Here’s a defense:
http://www.monroeworld.com/forums/showthread.php?271-Star-Trek-The-Next-Generation-lost-script
“How do you fight against THAT?”
Easy. There is nothing here worth the bother of interstellar travel, ergo nothing to fight.
“How do you fight against THAT?”
Easy. There is nothing here worth the bother of interstellar travel, ergo nothing to fight.