In physics and cosmology, the anthropic principle is the philosophical argument that observations of the physical Universe must be compatible with the conscious life that observes it. ~wikipedia
There are a few threads on this board as well as some JW publications which ask; why is the earth just the perfect distance from the sun for life? Why do we have the right balance of gases and chemicals for the existance of life? Is it just coincidence?
What they fail to see is that we are only ABLE to ask these questions at all BECAUSE we are in that situation which allows life to flourish. A million other alien species may have died out because their planet wasn't just right or it got hit by an asteroid. A million other alien species will never get to ask the questions at all, because they never had the right combination of factors to allow life to exist in the first place.
Another way of putting it is, we ask why is the sun 'just so' and not a mile this way or a mile that, and the answer is; because if it was, you wouldn't be here in order to ask the question.