We Cannot Argue Statistically

In discussing life in the Universe, we often hear one of two extreme views: "life is so unique that it is unlikely to have happened anywhere else", or "there are so many stars out there, how could life not have formed in many other places?". But in the absence of further information, neither of these is a very scientific statement. We cannot argue statistically from a single case, and we must define what we mean if "life is unique".

Our only hope is either to find at least one other example of life, or to understand as deeply as possible the conditions defining our own existence so that we can evaluate whether at least the conditions exist for life elsewhere.