> But the universe is unimaginably enormous, and the chances of any two such life forms being within reach of each other is miniscule. In order for it not to be

> But the universe is unimaginably enormous, and the chances of any two such life forms being within reach of each other is miniscule. In order for it not to be, the universe would have to be absolutely packed with such life, and if it were, we'd very likely have some sort of evidence of it. Yes, this is where we differ. Even at sub-light speeds, an advanced civilization would take only a few million years to colonize the entire galaxy. Thus, distances within a galaxy are trivial for intelligent life. Observable-universe-tier distances, however, are not - if we stay within sub-light speeds. If we assume that intelligent life could have emerged only within the last billion years, the observable universe would need to have quite many intelligent lifeforms indeed for some to have reached us. But then again, that's only a question of numbers. We have no idea of the probability of intelligence emerging and reaching space age. It could be very low or very high. We cannot make inferences about distances due to this. We can only consider evidence. If the universe and our galaxy was packed with life, and we assume they would not want to interfere with our development, what evidence would we have? Personally I can come up with no other possible evidence than radio signals. We can't image other solar systems yet with our equipment. Detecting Dyson spheres under construction is a reach for a number of reasons. And radio signals may easily be phased out very quickly as means of communication - we have only been using them for 100 years or so. This is why I don't find it convincing to use lack of evidence as evidence - what evidence would there be which we could detect short of direct contact? > Of all of the very unlikely things that might be true, why fixate so hard on this one? My suspicion is because people want it to be true, and starting with that stance makes error and misunderstanding very likely. You may be right on this point. However, I also believe that the historical stigma on discussing the extraterrestial scenario as a realistic possibility clouds the judgement of many towards overt caution, using strawmen where steelmen should be used. Evidence we have on the general subject points to no direction. Thus it's a question of probability for a very simple event - an intelligence reaching space age in any given planet, which we (almost) know to be non-zero. Therefore things like pooling extraterrestials together with wizards further strenghtens the stigma which greatly inhibits assessment of probabilities for explaining unexplained phenomena.