“Any sufficiently advanced civilization is … “

Clarke's Three Laws are three "laws" of prediction formulated by the British writer and scientist Arthur C. Clarke. They are:

  1. When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong. 
  2. The only way of discovering the limits of the possible is to venture a little way past them into the impossible. 
  3. Any sufficiently advanced technology is indistinguishable from magic.

— Wikipedia, Clarke's Three Laws

So are we alone? Well, there is one other possibility, at this point. I've lately been trumpeting my revision of Clarke's Law (which originally said 'any sufficiently advanced technology is indistinguishable from magic'). My revision says that any sufficiently advanced technology is indistinguishable from Nature. (Astute readers will recognize this as a refinement and further advancement of my argument in Permanence.) Basically, either advanced alien civilizations don't exist, or we can't see them because they are indistinguishable from natural systems. I vote for the latter.

— Karl Schroeder, The Deepening Paradox