[RonHolzwarth]

re: "it has to be admitted that conscious thought and intelligence is a remarkable development that does not easily occur."

Rather bold statement. What do we REALLY KNOW???

There has been so much learned in the last century, the last decade, and within the last year, that we just can't know such things yet, is my opinion.

[thoughtomator]

We know that there is an absence of signs that are perceptible to us of intelligent life elsewhere. Our "eyes" are decent, and have a substantial range, but no matter how hard we search we can find no sign of intelligent life.

It could be that we have already found signs of intelligent life but failed to comprehend them or realize their significance.

But if intelligent life were reasonably common, given the size of the universe, doesn't the probability indicate that at least one would be persistently sending out signals to contact other civilizations as we do?

Granted, it's all speculation. We "know" very little. But Occam's Razor indicates that the simplest explanation - that we are the only ones - is the best working theory, until there is evidence otherwise. If you're going to discard Occam's Razor, then we can ask, are there fairies in the 5th-7th dimensions that prance about and cause people to fall in love?... and other similarly ridiculous questions, that would be equally plausible under the assumption that what we do not know might be true.