Odin1,
There is of course the disease factor. What new and exotic plagues could result from first contact with space aliens, must give us pause. It's true that the Spaniards brought more than religion to the Americas. Religion was bad enough, for in its sake all manner of culture was destroyed. The Incas and Aztecs had written languages and traditions which the church suppressed and destroyed in the name of religion. How might we respond to an extraterrestrial who insisted on us converting to their religion? Conversely, what would we give up in order to know the secret of living longer, say to 200 years of age instead of the 100 we now accept as the general limit? Would ET care about our concerns in this regard? What if ET is a giant squid which communicates with others by changing color and pattern, and does not consider our written language to be of any use? I'm not so sure I want to meet ET, for I think he/she/it will be far more different than similar to us.
