Friar Bellows

The fact is, somewhere out there in the universe life either has or hasn't arisen. This does not necessarily render "totally irrelevant" a calculation or estimation of the odds of it. Only total knowledge or zero knowledge of the relevant facts would do that. We're at neither extreme. Therefore, we are justified in working on the calculation of these odds. Unfortunately, we're only barely justified, because the sole knowledge we have of life in the Universe is life on Earth. Not much of a sample space to do statistics with. On the other hand, the odds depend on the enivironment in which life might arise, and we do have a fair amount of knowledge of environments beyond our Solar System.