Quote Originally Posted by Dave Sell View Post
I'm not denying that a non-zero chance exists but there is zero evidence to support it - Ergo, how can you be confident about something for which zero evidence exists?
Zero evidence exists, yet we can be quite confident in saying that we couldn't detect it if it did exist. That's the same as not looking, which makes the universe a black box, in which case, if there is x probability that some situation will arise, then you can say that the situation will arise with x probability. In this case, x happens to be 100%, so EntityX is saying that he is completely confident that a 100% probability of 100% is certain. Nothing special about that.

On the other hand, if we were looking in a way that has a chance of success (SETI will only succeed if alien life forms are both deliberately, and effectively, trying to make contact, it is otherwise hopeless), then the fact that we have not found anything means that the box is not black, and the probability of the situation is skewed by our failure. In other words, if we search in an effective manner for some reasonable amount of time, and find nothing, then the probability that there is something to find keeps diminishing. Since we are not searching, then the probability is not influenced by our actions.