You and I are evidence. We are part of an advanced (or at least, spacefaring) technological civilization, and we are alien to everything else in the universe. Therefore, we know other alien civilizations are possible. One is much greater than zero in this case.
It’s a simple probabilistic argument: P(other alien civilizations exist | we exist) > P(other alien civilizations exist | we do not exist). Our existence is statistical evidence in favor of other civilizations existing elsewhere.
Similarly, the fact that we observed planets in our solar system should have increased our belief that other planets exist elsewhere. Then again, Giordano Bruno (https://en.m.wikipedia.org/wiki/Giordano_Bruno) was burned at the stake for pointing this out.
To be honest, the dominant source of nonsense around here is sneering comments that contribute absolutely nothing to thoughtful conversation.
The question is not about whether alien civilizations exist (very likely yes) but whether they can meet. Other civilizations existing is necessary but not remotely sufficient to prove that meetings are possible, let alone probable. That's where you equivocated, and I believe that calling out and naming fallacies is a worthwhile contribution.
Ed: but I guess you weren't doing it on purpose. I retract the "cute".
