If you are going to roll the dice six times and the first two times do not come up with a six, does your probability increase that one of the next 4 times you will get a six (it s a little simplified, but that's the gist of it)?
As to the probability of life elsewhere in the universe, I have another analogy.
Let's say that I have a huge warehouse stacked to the ceiling with tiny little tiles. All of them are face down. I ask you to randomly pick one of these tiles, and you do so. You flip it over and see that it has the number 42 on it (homage to Mr. Adams).
With just that information, what are the odds that you would have picked a tile with the number 42 on it?