Reply #21: I do not doubt the existence of life on other planets.

[Basileus Basileon]

Intelligent life probably, though intelligence on Earth was something of an enormous aberration--it's extremely costly to develop, it consumes an enormous amount of energy to maintain, it requires an extremely long development and dangerous childbirthing, and provides little advantage in most cases. We are fortunate in that our ancestors were bipedal, had hands, forward-facing eyes, were social, and had rudiments of verbal communication in place. Were any of those not the case, we would not have developed as we did.

Dinosaurs were stupid. So were most of the dominant forms of life. Looking at life before extinction events, there were several paradigms that were seemingly indestructible. There was aquatic armor; that died off in an extinction event. There was reptilian gigantism; that died off in an extinction event. As you state, intelligence developed very rapidly among humans. The fact that it only developed once in Earth's history, took as long as it did to develop (even still, social, sedentary society only developed once) all ought to tell you something about its likelihood of developing. It still almost certainly exists in our galaxy.

Of course, the visible sky is only a very small fraction of our galaxy, and mechanical transport is bounded by the speed of light. The odds that intelligent life has found us? Decreasing. The odds that intelligent life is paying us random little zip-and-and-out visits in mechanical craft? Extremely unlikely.