wrt to aliens<br>he's forgetting cryptography. Human cryptography can already make our communication appear as white noise. Alien interstellar communication will be even more like white noise. Also, the idea of lots of different aliens species communicating works only for the early universe.  Later than that, one species and their super AI will conquer the galaxy and zap all new comers.<br>Either / or <br>a) we haven't advanced to be a threat enough to be zapped<br>b) we haven't advanced to read alien communication<br>c) we are alone<br><br><br>dyson spheres and rings aren't necessary; aliens get all the power they need from nuclear reactions in their power stations