There's another factor to consider in my opinion. Namely:<br><br>The odds of two civilizations existing in the same galaxy/neighboring galaxies, for a long enough period, and during the same/overlapping epoch, to communicate with each other. <br><br>In my view, this is extremely low, and would be in yours as well assuming a 10,000 year civilization lifespan. From this perspective, especially given our current understanding of physics, it is extremely likely we are, at least functionally, alone.,(reply>), Eh